2024/04/25 更新

写真a

オオツカ モトユキ
大塚 基之
Otsuka Motoyuki
所属
医歯薬学域 教授
職名
教授

学位

  • 医博 ( 東京大学 )

研究キーワード

  • ウイルス発癌

  • non-coding RNA

  • バイオマーカー

  • 消化器がん

  • 炎症性発癌

  • ゲノム医学

  • 分子生物学

  • 消化器病学

研究分野

  • ライフサイエンス / 病態医化学

  • ライフサイエンス / 免疫学

  • ライフサイエンス / 消化器内科学

  • ライフサイエンス / ウイルス学

学歴

  • 東京大学    

    1998年4月 - 2002年3月

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  • 東京大学   Faculty of Medicine   School of Medicine

    1988年4月 - 1994年3月

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  • 鹿児島ラ・サール高校 卒業    

    1988年3月

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経歴

  • 岡山大学   学術研究院医歯薬学域 消化器肝臓内科学   教授

    2023年1月 - 現在

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  • 東京大学 大学院医学系研究科   器官病態内科学講座 消化器内科学   講師

    2017年4月 - 2022年12月

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  • 科学技術振興機構   さきがけ研究員(兼任)

    2012年10月 - 2016年3月

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  • 東京大学 医学部附属病院 消化器内科   助教

    2009年3月 - 2017年4月

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  • スクリプス研究所 免疫微生物学部門   研究員

    2004年7月 - 2009年2月

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  • 東京大学   医学部附属病院 消化器内科   特任講師(病院)

    2014年3月 - 2017年4月

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  • ウイルス肝炎研究財団   リサーチレジデント(兼任)

    2002年12月 - 2004年7月

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  • 東京大学   医学部附属病院消化器内科   研修登録医

    2002年7月 - 2004年7月

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  • 東京大学   医学部附属病院消化器内科   医員

    2002年5月 - 2002年6月

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  • 東京大学 医学部附属病院消化器内科   研修登録医

    2002年4月 - 2002年5月

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  • ヘリックス研究所第三研究部門   研究員(兼任)

    2000年7月 - 2001年12月

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  • 総合病院 国保 旭中央病院   医員

    1995年6月 - 1997年12月

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  • 東京大学医学部附属病院   研修医

    1994年6月 - 1995年5月

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▼全件表示

所属学協会

▼全件表示

委員歴

  • AMED課題評価委員会 委員  

    2023年7月 - 2025年3月   

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  • 加藤記念バイオサイエンス振興財団 選考委員  

    2023年4月 - 2027年3月   

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  • 日本消化器病学会/日本肝臓学会 NAFLD/NASHガイドライン作成委員  

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論文

  • An unusual case of gastric polyposis. 査読 国際誌

    Masaya Iwamuro, Seiji Kawano, Motoyuki Otsuka

    Gastroenterology   165 ( 5 )   1110 - 1113   2023年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1053/j.gastro.2023.07.027

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  • A rare case of severe colitis associated with a pancreatic neuroendocrine tumor. 査読 国際誌

    Ryosuke Sato, Shigeru Horiguchi, Motoyuki Otsuka

    Gastroenterology   2023年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1053/j.gastro.2023.07.012

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  • Machine learning for individualized prediction of hepatocellular carcinoma development after the eradication of hepatitis C virus with antivirals. 国際誌

    Tatsuya Minami, Masaya Sato, Hidenori Toyoda, Satoshi Yasuda, Tomoharu Yamada, Takuma Nakatsuka, Kenichiro Enooku, Hayato Nakagawa, Hidetaka Fujinaga, Masashi Izumiya, Yasuo Tanaka, Motoyuki Otsuka, Takamasa Ohki, Masahiro Arai, Yoshinari Asaoka, Atsushi Tanaka, Kiyomi Yasuda, Hideaki Miura, Itsuro Ogata, Toshiro Kamoshida, Kazuaki Inoue, Ryo Nakagomi, Masatoshi Akamatsu, Hiroshi Mitsui, Hajime Fujie, Keiji Ogura, Koji Uchino, Hideo Yoshida, Kazuyuki Hanajiri, Tomonori Wada, Kiyohiko Kurai, Hisato Maekawa, Yuji Kondo, Shuntaro Obi, Takuma Teratani, Naohiko Masaki, Kayo Nagashima, Takashi Ishikawa, Naoya Kato, Hiroshi Yotsuyanagi, Kyoji Moriya, Takashi Kumada, Mitsuhiro Fujishiro, Kazuhiko Koike, Ryosuke Tateishi

    Journal of hepatology   2023年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND AND AIMS: Accurate risk stratification for hepatocellular carcinoma (HCC) after achieving a sustained viral response (SVR) is necessary for optimal surveillance. We aimed to develop and validate a machine learning (ML) model to predict the risk of HCC after achieving an SVR in individual patients. METHODS: In this multicenter cohort study, 1742 patients with chronic hepatitis C who achieved an SVR were enrolled. Five ML models were developed including DeepSurv, gradient boosting survival analysis, random survival forest (RSF), survival support vector machine, and a conventional Cox proportional hazard model. Model performance was evaluated using Harrel' c-index and was externally validated in an independent cohort (977 patients). RESULTS: During the mean observation period of 5.4 years, 122 patients developed HCC (83 in the derivation cohort and 39 in the external validation cohort). The RSF model showed the best discrimination ability using seven parameters at the achievement of an SVR with a c-index of 0.839 in the external validation cohort and a high discriminative ability when the patients were categorized into three risk groups (P <0.001). Furthermore, this RSF model enabled the generation of an individualized predictive curve for HCC occurrence for each patient with an app available online. CONCLUSIONS: We developed and externally validated an RSF model with good predictive performance for the risk of HCC after an SVR. The application of this novel model is available on the website. This model could provide the data to consider an effective surveillance method. Further studies are needed to make recommendations for surveillance policies tailored to the medical situation in each country. IMPACT AND IMPLICATIONS: A novel prediction model for HCC occurrence in patients after hepatitis C virus eradication was developed using machine learning algorithms. This model, using seven commonly measured parameters, has been shown to have a good predictive ability for HCC development and could provide a personalized surveillance system.

    DOI: 10.1016/j.jhep.2023.05.042

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  • Recent advances in extracellular vesicles in gastrointestinal cancer and lymphoma. 査読 国際誌

    Motoyuki Otsuka, Ai Kotani

    Cancer science   114 ( 6 )   2230 - 2237   2023年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Extracellular vesicles (EVs) are intercellular communication agents that transfer microRNAs (miRNAs), other non-coding RNAs (ncRNAs), messenger RNAs (mRNAs), proteins, lipids, metabolites, and other molecules from donor cells (e.g., cancer cells) to recipient cells (e.g., stromal cells). In 2007, miRNAs were reported to be abundant among the ncRNAs present in EVs. Since then, many studies have investigated the functions of miRNAs and have attempted to apply these molecules to aid in the diagnosis and treatment of cancer. Research on EVs has expanded, particularly in the field of cancer, because cancer cells heavily secrete EVs. The cargo of these EVs, especially those in small EVs such as exosomes, is assumed to work cooperatively and significantly in the tumor microenvironment and to promote metastasis. In this review, we first summarize recent studies on EVs in gastrointestinal cancer and highlight studies on human satellite II RNAs, which are a type of ncRNA found in EVs and possessing repetitive sequences. Second, since several recent studies have revealed that phospholipids, which are components of EV membranes, play important roles in intercellular communication and in the generation of lipid mediators in the tumor microenvironment, we review the reported roles of these molecules and discuss their potential use in the design of new cancer treatments.

    DOI: 10.1111/cas.15771

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  • Combination of serum human satellite RNA and miR-21-5p levels as a biomarker for pancreatic cancer. 査読 国際誌

    Takahiro Seimiya, Tatsunori Suzuki, Takuma Iwata, Takahiro Kishikawa, Kazuma Sekiba, Chikako Shibata, Kazunaga Ishigaki, Hiroaki Fujiwara, Hiroki Oyama, Sachiko Kanai, Tatsuya Sato, Yousuke Nakai, Rei Ishibashi, Masaru Moriyama, Ryo Nakagawa, Hideaki Ijichi, Motoyuki Otsuka, Kazuhiko Koike

    iScience   26 ( 2 )   106021 - 106021   2023年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis due to the difficulty of its diagnosis. Because human satellite II (HSATII) RNA, a satellite repeat RNA, is highly and specifically expressed in human PDAC, the serum HSATII RNA level may be a biomarker of PDAC. To measure the serum HSATII RNA level with high sensitivity and reproducibility, we previously developed a convenient method, tandem repeat amplification by nuclease protection (TRAP) combined with droplet digital PCR (ddPCR). Here, we refined the original method by simultaneously measuring the serum miR-21-5p level to enhance the detection of PDAC. The resulting PDAC-Index, constructed using serum HSATII RNA and miR-21-5p levels, discriminated patients with PDAC with high accuracy. We verified the clinical usefulness of the PDAC-Index as a supportive test in difficult-to-diagnose cases. The PDAC-Index has satisfactory diagnostic performance and may routinely be applied for detecting PDAC.

    DOI: 10.1016/j.isci.2023.106021

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  • Overcoming T-cell exhaustion: new therapeutic targets in HCC immunotherapy. 招待 査読 国際誌

    Takahiro Seimiya, Motoyuki Otsuka, Mitsuhiro Fujishiro

    Hepatology (Baltimore, Md.)   78 ( 4 )   1009 - 1011   2023年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1097/HEP.0000000000000039

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  • Lipolysis by pancreatic cancer-derived extracellular vesicles in cancer-associated cachexia via specific integrins. 査読 国際誌

    Chikako Shibata, Motoyuki Otsuka, Takahiro Seimiya, Takahiro Kishikawa, Kazunaga Ishigaki, Mitsuhiro Fujishiro

    Clinical and translational medicine   12 ( 11 )   e1089   2022年11月

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    記述言語:英語  

    DOI: 10.1002/ctm2.1089

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  • Circulating Tumor DNA Guiding Adjuvant Therapy in Colon Cancer. 査読 国際誌

    Motoyuki Otsuka

    The New England Journal of Medicine   387 ( 8 )   759 - 760   2022年8月

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    記述言語:英語  

    DOI: 10.1056/NEJMc2209374

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  • MNX1-HNF1B Axis Is Indispensable for Intraductal Papillary Mucinous Neoplasm Lineages. 査読 国際誌

    Hiroyuki Kato, Keisuke Tateishi, Hiroaki Fujiwara, Takuma Nakatsuka, Keisuke Yamamoto, Yotaro Kudo, Yoku Hayakawa, Hayato Nakagawa, Yasuo Tanaka, Hideaki Ijichi, Motoyuki Otsuka, Dosuke Iwadate, Hiroki Oyama, Sachiko Kanai, Kensaku Noguchi, Tatsunori Suzuki, Tatsuya Sato, Ryunosuke Hakuta, Kazunaga Ishigaki, Kei Saito, Tomotaka Saito, Naminatsu Takahara, Takahiro Kishikawa, Tsuyoshi Hamada, Ryota Takahashi, Koji Miyabayashi, Suguru Mizuno, Hirofumi Kogure, Yousuke Nakai, Yoshihiro Hirata, Atsushi Toyoda, Kazuki Ichikawa, Wei Qu, Shinichi Morishita, Junichi Arita, Mariko Tanaka, Tetsuo Ushiku, Kiyoshi Hasegawa, Mitsuhiro Fujishiro, Kazuhiko Koike

    Gastroenterology   162 ( 4 )   1272 - 1287   2022年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND & AIMS: Chromatin architecture governs cell lineages by regulating the specific gene expression; however, its role in the diversity of cancer development remains unknown. Among pancreatic cancers, pancreatic ductal adenocarcinoma (PDAC) and intraductal papillary mucinous neoplasms (IPMN) with an associated invasive carcinoma (IPMNinv) arise from 2 distinct precursors, and their fundamental differences remain obscure. Here, we aimed to assess the difference of chromatin architecture regulating the transcriptional signatures or biological features in pancreatic cancers. METHODS: We established 28 human organoids from distinct subtypes of pancreatic tumors, including IPMN, IPMNinv, and PDAC. We performed exome sequencing (seq), RNA-seq, assay for transposase-accessible chromatin-seq, chromatin immunoprecipitation-seq, high-throughput chromosome conformation capture, and phenotypic analyses with short hairpin RNA or clustered regularly interspaced short palindromic repeats interference. RESULTS: Established organoids successfully reproduced the histology of primary tumors. IPMN and IPMNinv organoids harbored GNAS, RNF43, or KLF4 mutations and showed the distinct expression profiles compared with PDAC. Chromatin accessibility profiles revealed the gain of stomach-specific open regions in IPMN and the pattern of diverse gastrointestinal tissues in IPMNinv. In contrast, PDAC presented an impressive loss of accessible regions compared with normal pancreatic ducts. Transcription factor footprint analysis and functional assays identified that MNX1 and HNF1B were biologically indispensable for IPMN lineages. The upregulation of MNX1 was specifically marked in the human IPMN lineage tissues. The MNX1-HNF1B axis governed a set of genes, including MYC, SOX9, and OLFM4, which are known to be essential for gastrointestinal stem cells. High-throughput chromosome conformation capture analysis suggested the HNF1B target genes to be 3-dimensionally connected in the genome of IPMNinv. CONCLUSIONS: Our organoid analyses identified the MNX1-HNF1B axis to be biologically significant in IPMN lineages.

    DOI: 10.1053/j.gastro.2021.12.254

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  • WWP1 inactivation enhances efficacy of PI3K inhibitors while suppressing their toxicities in breast cancer models. 国際誌

    Takahiro Kishikawa, Hiroshi Higuchi, Limei Wang, Nivedita Panch, Valerie Maymi, Sachem Best, Samuel Lee, Genso Notoya, Alex Toker, Lydia E Matesic, Gerburg M Wulf, Wenyi Wei, Motoyuki Otsuka, Kazuhiko Koike, John G Clohessy, Yu-Ru Lee, Pier Paolo Pandolfi

    The Journal of clinical investigation   131 ( 24 )   2021年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Activation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway is a pervasive event in tumorigenesis due to PI3K mutation and dysfunction of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Pharmacological inhibition of PI3K has resulted in variable clinical outcomes, however, raising questions regarding the possible mechanisms of unresponsiveness and resistance to treatment. WWP1 is an oncogenic HECT-type ubiquitin E3 ligase frequently amplified and mutated in multiple cancers, as well as in the germ lines of patients predisposed to cancer, and was recently found to activate PI3K signaling through PTEN inactivation. Here, we demonstrate that PTEN dissociated from the plasma membrane upon treatment with PI3K inhibitors through WWP1 activation, whereas WWP1 genetic or pharmacological inhibition restored PTEN membrane localization, synergizing with PI3K inhibitors to suppress tumor growth both in vitro and in vivo. Furthermore, we demonstrate that WWP1 inhibition attenuated hyperglycemia and the consequent insulin feedback, which is a major tumor-promoting side effect of PI3K inhibitors. Mechanistically, we found that AMPKα2 was ubiquitinated and, in turn, inhibited in its activatory phosphorylation by WWP1, whereas WWP1 inhibition facilitated AMPKα2 activity in the muscle to compensate for the reduction in glucose uptake observed upon PI3K inhibition. Thus, our identification of the cell-autonomous and systemic roles of WWP1 inhibition expands the therapeutic potential of PI3K inhibitors and reveals new avenues of combination cancer therapy.

    DOI: 10.1172/JCI140436

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  • HBx-induced degradation of Smc5/6 complex impairs homologous recombination-mediated repair of damaged DNA. 査読 国際誌

    Kazuma Sekiba, Motoyuki Otsuka, Kazuyoshi Funato, Yu Miyakawa, Eri Tanaka, Takahiro Seimiya, Mari Yamagami, Takeya Tsutsumi, Kazuya Okushin, Kei Miyakawa, Akihide Ryo, Kazuhiko Koike

    Journal of hepatology   76 ( 1 )   53 - 62   2021年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND & AIMS: Hepatitis B virus (HBV) causes hepatocellular carcinoma (HCC). While the need for HBV regulatory protein X (HBx) for viral transcription via impairment of the structural maintenance of chromosome 5/6 (Smc5/6) complex was recently demonstrated, HBx is also a potent driver of HCC. However, the mechanism by which HBx expression induces hepatocarcinogenesis is unclear. METHODS: Degradation of Smc5/6 complex and accumulation of DNA damage were observed in both in vivo and in vitro HBV infection models. Rescue experiments were performed using nitazoxanide (NTZ), which inhibits degradation of the Smc5/6 complex by HBx. RESULTS: Degradation of the Smc5/6 complex triggered by HBx impaired homologous recombination (HR) repair of DNA double-strand breaks (DSBs), leading to cellular transformation. We found that DNA damage accumulated in the liver tissue of HBV-infected humanized chimeric mice, HBx-transgenic mice, and human tissues. HBx suppressed the HR repair of DSBs, including that induced by the clustered regularly interspaced short palindromic repeats-Cas9 system, in an Smc5/6-dependent manner, which was rescued by restoring the Smc5/6 complex. NTZ restored HR repair in, and colony formation by, HBx-expressing cells. CONCLUSIONS: Degradation of the Smc5/6 complex by HBx increases viral transcription and promotes cellular transformation by impairing HR repair of DSBs. LAY SUMMARY: HBV regulatory protein X (HBx) degrades the structural maintenance of chromosome 5/6 (Smc5/6) complex, which is required for viral replication. We found that degradation of the Smc5/6 complex also plays a key role in the accumulation of DNA damage, as well as in HBx-mediated tumorigenesis.

    DOI: 10.1016/j.jhep.2021.08.010

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  • Impact of Obesity and Heavy Alcohol Consumption on Hepatocellular Carcinoma Development after HCV Eradication with Antivirals. 査読 国際誌

    Tatsuya Minami, Ryosuke Tateishi, Naoto Fujiwara, Ryo Nakagomi, Takuma Nakatsuka, Masaya Sato, Koji Uchino, Kenichiro Enooku, Hayato Nakagawa, Hidetaka Fujinaga, Masashi Izumiya, Kazuyuki Hanajiri, Yoshinari Asaoka, Yuji Kondo, Yasuo Tanaka, Motoyuki Otsuka, Takamasa Ohki, Masahiro Arai, Atsushi Tanaka, Kiyomi Yasuda, Hideaki Miura, Itsuro Ogata, Toshiro Kamoshida, Kazuaki Inoue, Yukihiro Koike, Masatoshi Akamatsu, Hiroshi Mitsui, Hajime Fujie, Keiji Ogura, Hideo Yoshida, Tomonori Wada, Kiyohiko Kurai, Hisato Maekawa, Shuntaro Obi, Takuma Teratani, Naohiko Masaki, Kayo Nagashima, Takashi Ishikawa, Naoya Kato, Kyoji Moriya, Hiroshi Yotsuyanagi, Kazuhiko Koike

    Liver cancer   10 ( 4 )   309 - 319   2021年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Background and Aims: It remains unclear whether obesity increases the risk of hepatocellular carcinoma (HCC) in patients with chronic hepatitis C who achieved a sustained virological response (SVR) with antiviral therapy. Methods: In this multicenter cohort study, we enrolled patients with chronic hepatitis C who achieved SVR with interferon (IFN)-based therapy (IFN group) or direct-acting antiviral (DAA) therapy (DAA group) between January 1, 1990, and December 31, 2018. The patients underwent regular surveillance for HCC. Cumulative incidence of and the risk factors for HCC development after SVR were assessed using the Kaplan-Meier method and Cox proportional hazard regression analysis, respectively. Results: Among 2,055 patients (840 in the IFN group and 1,215 in the DAA group), 75 developed HCC (41 in the IFN group and 34 in the DAA group) during the mean observation period of 4.1 years. The incidence rates of HCC at 1, 2, and 3 years were 1.2, 1.9, and 3.0%, respectively. Multivariate analysis revealed that in addition to older age, lower albumin level, lower platelet count, higher alpha-fetoprotein level, and absence of dyslipidemia, obesity (body mass index ≥25 kg/m2) and heavy alcohol consumption (≥60 g/day) were independent risk factors for HCC development, with adjusted hazard ratio (HR) of 2.53 (95% confidence interval [CI]: 1.51-4.25) and 2.56 (95% CI: 1.14-5.75), respectively. The adjusted HR was not significant between the 2 groups (DAA vs. IFN; HR 1.19, 95% CI: 0.61-2.33). Conclusions: Obesity and heavy alcohol consumption increased the risk of HCC development after SVR.

    DOI: 10.1159/000513705

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  • Aberrant expression of a novel circular RNA in pancreatic cancer. 査読 国際誌

    Takahiro Seimiya, Motoyuki Otsuka, Takuma Iwata, Eri Tanaka, Kazuma Sekiba, Chikako Shibata, Masaru Moriyama, Ryo Nakagawa, Reo Maruyama, Kazuhiko Koike

    Journal of human genetics   66 ( 2 )   181 - 191   2021年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Circular RNAs (circRNAs) are single-stranded, covalently closed RNA molecules that are produced from pre-mRNAs through a process known as back-splicing. Although circRNAs are expressed under specific conditions, current understanding of their comprehensive expression status is still limited. Here, we performed a large-scale circRNA profiling analysis in human pancreatic ductal adenocarcinoma (PDAC) tissues, using circular RNA-specific RNA sequencing. We identified more than 40,000 previously unknown circRNAs, some of which were upregulated in PDAC tissues, compared with normal pancreatic tissues. We determined the full-length sequence of a circRNA upregulated in PDAC, which was derived from two noncoding RNA loci on chromosome 12. The novel circRNA, named circPDAC RNA, was not expressed in normal human cells, but was expressed in PDAC and other carcinoma cells. While postulated biological functions, such as peptide production from the circPDAC RNA, were not detected, its aberrant expression was confirmed in other PDAC tissues and in serum from a PDAC patient. These results demonstrate that comprehensive studies are necessary to reveal the expression status of circRNAs and that the circPDAC RNA identified here might serve as a novel biomarker for cancers, including PDAC.

    DOI: 10.1038/s10038-020-00826-5

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  • Should Level of HBV RNA be Used to Determine When Patients Should Stop Treatment With Nucleos(t)ide Analogues. 査読 国際誌

    Motoyuki Otsuka, Kazuhiko Koike

    Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association   18 ( 3 )   551 - 552   2020年3月

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  • Pevonedistat, a Neuronal Precursor Cell-Expressed Developmentally Down-Regulated Protein 8-Activating Enzyme Inhibitor, Is a Potent Inhibitor of Hepatitis B Virus. 査読 国際誌

    Kazuma Sekiba, Motoyuki Otsuka, Motoko Ohno, Mari Yamagami, Takahiro Kishikawa, Takahiro Seimiya, Tatsunori Suzuki, Eri Tanaka, Rei Ishibashi, Kazuyoshi Funato, Kazuhiko Koike

    Hepatology (Baltimore, Md.)   69 ( 5 )   1903 - 1915   2019年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Hepatitis B virus (HBV) infection is a major health concern worldwide. To prevent HBV-related mortality, elimination of viral proteins is considered the ultimate goal of HBV treatment; however, currently available nucleos(t)ide analogs rarely achieve this goal, as viral transcription from episomal viral covalently closed circular DNA (cccDNA) is not prevented. HBV regulatory protein X was recently found to target the protein structural maintenance of chromosomes 5/6 (Smc5/6) for ubiquitination and degradation by DDB1-CUL4-ROC1 E3 ligase, resulting in enhanced viral transcription from cccDNA. This ubiquitin-dependent proteasomal pathway requires an additional ubiquitin-like protein for activation, neuronal precursor cell-expressed developmentally down-regulated protein 8 (NEDD8). Here, we show that pevonedistat, a NEDD8-activating enzyme inhibitor, works efficiently as an antiviral agent. Pevonedistat significantly restored Smc5/6 protein levels and suppressed viral transcription and protein production in the HBV minicircle system in in vitro HBV replication models and in human primary hepatocytes infected naturally with HBV. Conclusion: These results indicate that pevonedistat is a promising compound to treat chronic HBV infection.

    DOI: 10.1002/hep.30491

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  • Repression of MicroRNA Function Mediates Inflammation-associated Colon Tumorigenesis 査読

    Takeshi Yoshikawa, Jianfeng Wu, Motoyuki Otsuka, Takahiro Kishikawa, Nobumi Suzuki, Akemi Takata, Motoko Ohno, Rei Ishibashi, Mari Yamagami, Ryo Nakagawa, Naoya Kato, Masaaki Miyazawa, Jiahuai Han, Kazuhiko Koike

    Gastroenterology   152 ( 3 )   631 - 643   2017年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:W B SAUNDERS CO-ELSEVIER INC  

    BACKGROUND & AIMS: Little is known about the mechanisms by which chronic inflammation contributes to carcinogenesis, such as the development of colon tumors in patients with inflammatory bowel diseases. Specific microRNA (miRNAs) can function as suppressors or oncogenes, and widespread alterations in miRNA expression have been associated with tumorigenesis. We studied whether alterations in miRNA function contribute to inflammation-associated colon carcinogenesis. METHODS: We studied the effects of inflammatory cytokines, such as tumor necrosis factor, interleukin-1 alpha (IL1A), and IL1 beta (IL1B), on miRNA function, measured by activity of reporter constructs containing miRNA-binding sites in their 30 untranslated regions, in human 293T embryonic kidney, Caco-2, HT29, and HCT116 colon carcinoma cells, as well as dicer(+/+) and dicer(-/-), and Apobec3(+/+) and Apobec3(-/-) mouse embryonic fibroblasts. Cells were analyzed by immunoblots, immunohistochemistry, and flow cytometry. We generated transgenic mice expressing reporter constructs regulated by LET7B, MIR122, and MIR29b response elements; some mice were given injections of miRNA inhibitors (anti-MIR122 or anti-LET7B), a negative control, or tumor necrosis factor. Liver tissues were collected and analyzed by immunoblotting. Reporter mice were given azoxymethane followed by dextran sulfate sodium to induce colitis and colon tumors; some mice were given the ROCK inhibitor fasudil along with these agents (ROCK inhibitors increase miRNA function). Colon tissues were collected and analyzed by immunohistochemistry, immunoblots, and fluorescence microscopy. RESULTS: Incubation of cell lines with inflammatory cytokines reduced the ability of miRNAs to down-regulate expression from reporter constructs; dicer was required for this effect, so these cytokines relieve miRNA-dependent reductions in expression. The cytokines promoted degradation of APOBEC3G, which normally promotes miRNA loading into argonaute 2-related complexes. Mice with colitis had reduced miRNA function, based on increased expression of reporter genes. Administration of fasudil to mice did not reduce the severity of colitis that developed but greatly reduced the numbers of colon tumors formed (mean 2 tumors/colon in mice given fasudil vs 9 tumors/colon in mice given control agent). We made similar observations in IL10-deficient mice. CONCLUSIONS: We found inflammatory cytokines to reduce the activities of miRNAs. In mice with colitis, activities of miRNAs are reduced; administration of an agent that increases miRNA function prevents colon tumor formation in these mice. This pathway might be targeted to prevent colon carcinogenesis in patients with inflammatory bowel diseases.

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  • Satellite RNAs promote pancreatic oncogenic processes via the dysfunction of YBX1 査読

    Takahiro Kishikawa, Motoyuki Otsuka, Takeshi Yoshikawa, Motoko Ohno, Hideaki Ijichi, Kazuhiko Koike

    Nature Communications   7 ( 1 )   13006   2016年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Nature  

    Highly repetitive tandem arrays at the centromeric and pericentromeric regions in chromosomes, previously considered silent, are actively transcribed, particularly in cancer. This aberrant expression occurs even in K-ras-mutated pancreatic intraepithelial neoplasia (PanIN) tissues, which are precancerous lesions. To examine the biological roles of the satellite RNAs in carcinogenesis, we construct mouse PanIN-derived cells expressing major satellite (MajSAT) RNA and show increased malignant properties. We find an increase in frequency of chromosomal instability and point mutations in both genomic and mitochondrial DNA. We identify Y-box binding protein 1 (YBX1) as a protein that binds to MajSAT RNA. MajSAT RNA inhibits the nuclear translocation of YBX1 under stress conditions, thus reducing its DNA-damage repair function. The forced expression of YBX1 significantly decreases the aberrant phenotypes. These findings indicate that during the early stage of cancer development, satellite transcripts may act as 'intrinsic mutagens' by inducing YBX1 dysfunction, which may be crucial in oncogenic processes.

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  • Quantitation of circulating satellite RNAs in pancreatic cancer patients. 査読 国際誌

    Takahiro Kishikawa, Motoyuki Otsuka, Takeshi Yoshikawa, Motoko Ohno, Keisuke Yamamoto, Natsuyo Yamamoto, Ai Kotani, Kazuhiko Koike

    JCI insight   1 ( 8 )   e86646   2016年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Pancreatic ductal adenocarcinoma (Pdac) is a malignancy with a poor prognosis due to difficulties in early detection. Although promising biomarkers are increasingly reported, such methods are not yet easy to apply clinically, mainly due to their low reproducibility or technical difficulties. In this study, we developed a convenient and sensitive method for quantifying aberrantly expressed satellite repeat RNAs in sera, which can be used to efficiently detect patients with Pdac. Here, we introduce a Tandem Repeat Amplification by nuclease Protection (TRAP) method combined with droplet digital PCR (ddPCR) to detect human satellite II (HSATII) RNAs, which are specifically expressed in human Pdacs at greater levels than normal tissues but are difficult to measure due to their repetitive sequences and irregularities. HSATII RNA core sequence levels in sera were significantly higher in Pdac patients compared with noncancer patients (median copy number: 14.75 and 3.17 per μl in the training set and 17.35 and 2.9 in the validation set, respectively). In addition, patients with intraductal papillary mucinous neoplasm (IPMN), a precancerous lesion of Pdac, could also be efficiently detected. This method can be routinely applied to screen patients with Pdac and high-risk patients, facilitating the development of preventive medicine for this disease.

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  • Regulation of NKT cell-mediated immune responses to tumours and liver inflammation by mitochondrial PGAM5-Drp1 signalling 査読

    Young Jun Kang, Bo-Ram Bang, Kyung Ho Han, Lixin Hong, Eun-Jin Shim, Jianhui Ma, Richard A. Lerner, Motoyuki Otsuka

    Nature Communications   6 ( 1 )   8371   2015年12月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Science and Business Media {LLC}  

    DOI: 10.1038/ncomms9371

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  • The TNF Family Member 4-1BBL Sustains Inflammation by Interacting with TLR Signaling Components During Late-Phase Activation 査読

    Jianhui Ma, Bo-Ram Bang, Jiawei Lu, So-Young Eun, Motoyuki Otsuka, Michael Croft, Peter Tobias, Jiahuai Han, Osamu Takeuchi, Shizuo Akira, Michael Karin, Hideo Yagita, Young Jun Kang

    Science Signaling   6 ( 295 )   ra87   2013年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER ASSOC ADVANCEMENT SCIENCE  

    Activation of Toll-like receptor (TLR)-dependent signaling leads to the expression of genes encoding proinflammatory factors, such as tumor necrosis factor-alpha (TNF-alpha), and this proinflammatory gene expression is sustained for the duration of the inflammatory response. TLR4-mediated inflammation, which occurs in two phases, depends on the TNF family member 4-1BB ligand (4-1BBL) to sustain TNF-alpha production during late-phase signaling. We showed that Toll-interleukin-1 receptor (TIR) domain-containing adaptor protein (TIRAP) and the kinase IRAK2 interacted with 4-1BBL to mediate late-phase TLR4 signaling. Expression of 4-1bbl depended on early TLR4 signaling that also induced Tnf expression, and 4-1BBL translocated to the plasma membrane, where it interacted with TLR4 to mediate late-phase signaling. TLR4-4-1BBL-mediated signaling depended on TIRAP and IRAK2, as well as a complex consisting of the E3 ubiquitin ligase TRAF6 (TNF receptor-associated factor 6), the kinase TAK1 (transforming growth factor-beta-activated kinase 1), and the adaptor protein TAB1 (TAK-binding protein 1). Inhibition of this late-phase pathway reduced the extent of TNF-alpha production by mouse macrophages exposed to the TLR4 ligand lipopolysaccharide (LPS) and ameliorated LPS-induced sepsis in mice. Together, these data suggest that TIRAP and IRAK2 are critical for the sustained inflammatory response that is mediated by late-phase signaling by the TLR-4-1BBL complex.

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  • Serum metabolomics reveals γ-glutamyl dipeptides as biomarkers for discrimination among different forms of liver disease. 査読

    Soga T, Sugimoto M, Honma M, Mori M, Igarashi K, Kashikura K, Ikeda S, Hirayama A, Yamamoto T, Yoshida H, Otsuka M, Tsuji S, Yatomi Y, Sakuragawa T, Watanabe H, Nihei K, Saito T, Kawata S, Suzuki H, Tomita M, Suematsu M

    Journal of Hepatology   55 ( 4 )   896 - 905   2011年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:4  

    DOI: 10.1016/j.jhep.2011.01.031

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  • MicroRNA122 is a key regulator of α-fetoprotein expression and influences the aggressiveness of hepatocellular carcinoma. 査読

    Kojima K, Takata A, Vadnais C, Otsuka M, Yoshikawa T, Akanuma M, Kondo Y, Kang YJ, Kishikawa T, Kato N, Xie Z, Zhang WJ, Yoshida H, Omata M, Nepveu A, Koike K

    Nature Communications   2   338   2011年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Genome-wide association study identifies a susceptibility locus for HCV-induced hepatocellular carcinoma 査読

    Nature Genetics   43 ( 5 )   455 - +   2011年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1038/ng.809

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  • Distinct Effects of p38 alpha Deletion in Myeloid Lineage and Gut Epithelia in Mouse Models of Inflammatory Bowel Disease 査読

    Gastroenterology   138 ( 4 )   1255 - U83   2010年4月

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  • Impaired microRNA processing causes corpus luteum insufficiency and infertility in mice 査読

    Journal of Clinical Investigation   118 ( 5 )   1944 - 1954   2008年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Hypersusceptibility to vesicular stomatitis virus infection in Dicer1-deficient mice is due to impaired miR24 and miR93 expression 査読

    Immunity   27 ( 1 )   123 - 134   2007年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.immuni.2007.05.014

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  • Cell surface 4-1BBL mediates sequential signaling pathways 'downstream' of TLR and is required for sustained TNF production in macrophages 査読

    Nature Immunology   8 ( 6 )   601 - 609   2007年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Methylation analysis of DCC gene in saliva samples is an efficient method for non-invasive detection of superficial hypopharyngeal cancer. 国際誌

    Ryosuke Hirai, Hideaki Kinugasa, Shumpei Yamamoto, Soichiro Ako, Koichiro Tsutsumi, Makoto Abe, Koji Miyahara, Masahiro Nakagawa, Motoyuki Otsuka

    British journal of cancer   2024年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: Advances in upper gastrointestinal endoscopic technology have enabled early detection and treatment of hypopharyngeal cancer. However, in-depth pharyngeal observations require sedation and are invasive. It is important to establish a minimally invasive and simple evaluation method to identify high-risk patients. METHODS: Eighty-seven patients with superficial hypopharyngeal cancer and 51 healthy controls were recruited. We assessed the methylation status of DCC, PTGDR1, EDNRB, and ECAD, in tissue and saliva samples and verified the diagnostic accuracy by methylation analyses of their promoter regions using quantitative methylation-specific PCR. RESULTS: Significant differences between cancer and their surrounding non-cancerous tissues were observed in the methylation values of DCC (p = 0.003), EDNRB (p = 0.001), and ECAD (p = 0.043). Using receiver operating characteristic analyses of the methylation values in saliva samples, DCC showed the highest area under the curve values for the detection of superficial hypopharyngeal cancer (0.917, 95% confidence interval = 0.864-0.970), compared with those for EDNRB (0.680) and ECAD (0.639). When the cutoff for the methylation values of DCC was set at ≥0.163, the sensitivity to detect hypopharyngeal cancer was 82.8% and the specificity was 90.2%. CONCLUSIONS: DCC methylation in saliva samples could be a non-invasive and efficient tool for early detection of hypopharyngeal cancer in high-risk patients.

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  • MicroRNA-34a-5p: A pivotal therapeutic target in gallbladder cancer. 国際誌

    Takashi Oda, Koichiro Tsutsumi, Taisuke Obata, Eijiro Ueta, Tatsuya Kikuchi, Soichiro Ako, Yuki Fujii, Tatsuhiro Yamazaki, Daisuke Uchida, Kazuyuki Matsumoto, Shigeru Horiguchi, Hironari Kato, Hiroyuki Okada, Ryota Chijimatsu, Motoyuki Otsuka

    Molecular therapy. Oncology   32 ( 1 )   200765 - 200765   2024年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Gallbladder cancer incidence has been increasing globally, and it remains challenging to expect long prognosis with the current systemic chemotherapy. We identified a novel nucleic acid-mediated therapeutic target against gallbladder cancer by using innovative organoid-based gallbladder cancer models generated from KrasLSL-G12D/+; Trp53f/f mice. Using comprehensive microRNA expression analyses and a bioinformatics approach, we identified significant microRNA-34a-5p downregulation in both murine gallbladder cancer organoids and resected human gallbladder cancer specimens. In three different human gallbladder cancer cell lines, forced microRNA-34a-5p expression inhibited cell proliferation and induced cell-cycle arrest at the G1 phase by suppressing direct target (CDK6) expression. Furthermore, comprehensive RNA sequencing revealed the significant enrichment of gene sets related to the cell-cycle regulators after microRNA-34a-5p expression in gallbladder cancer cells. In a murine xenograft model, locally injected microRNA-34a-5p mimics significantly inhibited gallbladder cancer progression and downregulated CDK6 expression. These results provide a rationale for promising therapeutics against gallbladder cancer by microRNA-34a-5p injection, as well as a strategy to explore therapeutic targets against cancers using organoid-based models, especially for those lacking useful genetically engineered murine models, such as gallbladder cancer.

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  • Satellite double-stranded RNA induces mesenchymal transition in pancreatic cancer by regulating alternative splicing. 国際誌

    Takuma Iwata, Takahiro Kishikawa, Takahiro Seimiya, Genso Notoya, Tatsunori Suzuki, Chikako Shibata, Yu Miyakawa, Nariaki Odawara, Kazuyoshi Funato, Eri Tanaka, Mari Yamagami, Kazuma Sekiba, Motoyuki Otsuka, Kazuhiko Koike, Mitsuhiro Fujishiro

    The Journal of biological chemistry   300 ( 3 )   105742 - 105742   2024年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Human satellite II (HSATII), composed of tandem repeats in pericentromeric regions, is aberrantly transcribed in epithelial cancers, particularly pancreatic cancer. Dysregulation of repetitive elements in cancer tissues can facilitate incidental dsRNA formation; however, it remains controversial whether dsRNAs play tumor-promoting or tumor-suppressing roles during cancer progression. Therefore, we focused on the double-stranded formation of HSATII RNA and explored its molecular function. The overexpression of double-stranded HSATII (dsHSATII) RNA promoted mesenchymal-like morphological changes and enhanced the invasiveness of pancreatic cancer cells. We identified an RNA-binding protein, spermatid perinuclear RNA-binding protein (STRBP), which preferentially binds to dsHSATII RNA rather than single-stranded HSATII RNA. The mesenchymal transition of dsHSATII-expressing cells was rescued by STRBP overexpression. Mechanistically, STRBP is involved in the alternative splicing of genes associated with epithelial-mesenchymal transition (EMT). We also confirmed that isoform switching of CLSTN1, driven by dsHSATII overexpression or STRBP depletion, induced EMT-like morphological changes. These findings reveal a novel tumor-promoting function of dsHSATII RNA, inducing EMT-like changes and cell invasiveness, thus enhancing our understanding of the biological significance of aberrant expression of satellite arrays in malignant tumors.

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  • Gut Bacteria-derived Membrane Vesicles Induce Colonic Dysplasia by Inducing DNA Damage in Colon Epithelial Cells. 国際誌

    Yu Miyakawa, Motoyuki Otsuka, Chikako Shibata, Takahiro Seimiya, Keisuke Yamamoto, Rei Ishibashi, Takahiro Kishikawa, Eri Tanaka, Takayuki Isagawa, Norihiko Takeda, Noriaki Kamio, Kenichi Imai, Mitsuhiro Fujishiro

    Cellular and molecular gastroenterology and hepatology   17 ( 5 )   745 - 767   2024年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND & AIMS: Colorectal cancer (CRC) is the third most common cancer in the world. Gut microbiota has recently been implicated in the development of CRC. Actinomyces odontolyticus is one of the most abundant bacteria in the gut of patients with very early stages of CRC. A odontolyticus is an anaerobic bacterium existing principally in the oral cavity, similar to Fusobacterium nucleatum, which is known as a colon carcinogenic bacterium. Here we newly determined the biological functions of A odontolyticus on colonic oncogenesis. METHODS: We examined the induction of intracellular signaling by A odontolyticus in human colonic epithelial cells (CECs). DNA damage levels in CECs were confirmed using the human induced pluripotent stem cell-derived gut organoid model and mouse colon tissues in vivo. RESULTS: A odontolyticus secretes membrane vesicles (MVs), which induce nuclear factor kappa B signaling and also produce excessive reactive oxygen species (ROS) in colon epithelial cells. We found that A odontolyticus secretes lipoteichoic acid-rich MVs, promoting inflammatory signaling via TLR2. Simultaneously, those MVs are internalized into the colon epithelial cells, co-localize with the mitochondria, and cause mitochondrial dysfunction, resulting in excessive ROS production and DNA damage. Induction of excessive DNA damage in colonic cells by A odontolyticus-derived MVs was confirmed in the gut organoid model and also in mouse colon tissues. CONCLUSIONS: A odontolyticus secretes MVs, which cause chronic inflammation and ROS production in colonic epithelial cells, leading to the initiation of CRC.

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  • MicroRNA-451a inhibits gemcitabine-refractory biliary tract cancer progression by suppressing the MIF-mediated PI3K/AKT pathway. 国際誌

    Taisuke Obata, Koichiro Tsutsumi, Eijiro Ueta, Takashi Oda, Tatsuya Kikuchi, Soichiro Ako, Yuki Fujii, Tatsuhiro Yamazaki, Daisuke Uchida, Kazuyuki Matsumoto, Shigeru Horiguchi, Hironari Kato, Hiroyuki Okada, Motoyuki Otsuka

    Molecular therapy. Nucleic acids   34   102054 - 102054   2023年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Gemcitabine is an effective chemotherapeutic agent for biliary tract cancers (BTCs), including gallbladder cancer (GBC) and cholangiocarcinoma (CCA). However, few other effective agents are currently available, particularly for GEM-refractory BTCs. We previously identified microRNA-451a (miR-451a) as a potential therapeutic target in GBC. To elucidate the antineoplastic effects of miR-451a and its underlying mechanisms, we transfected miR-451a into GBC, gemcitabine-resistant GBC (GR-GBC), and gemcitabine-resistant CCA (GR-CCA) cell lines. Furthermore, mimicking in vivo conditions, tumorigenic GBC organoids and three-dimensional (3D) cell culture systems were employed to investigate the anti-proliferative effects of miR-451a on BTCs, and its effect on stem cell properties. We found that miR-451a significantly inhibited cell proliferation, induced apoptosis, and reduced chemoresistant phenotypes, such as epithelial-mesenchymal transition, in both GBC and GR-GBC. The principal mechanism is probably the negative regulation of the phosphatidylinositol 3-kinase/AKT pathway, partially accomplished by directly downregulating macrophage migration inhibitory factor. The Gene Expression Omnibus database revealed that miR-451a was the most significantly downregulated microRNA in CCA tissues. The introduction of miR-451a resulted in similar antineoplastic effects in GR-CCA. Furthermore, miR-451a reduced cell viability in 3D spheroid models and tumorigenic GBC organoids. These findings suggest that the supplementation of miR-451a is a potential treatment strategy for GEM-refractory BTCs.

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  • Successful removal of a proximally migrated pancreatic stent using a novel device delivery system. 査読 国際誌

    Akihiro Matsumi, Kazuyuki Matsumoto, Daisuke Uchida, Shigeru Horiguchi, Koichiro Tsutsumi, Hironari Kato, Motoyuki Otsuka

    Endoscopy   55 ( S 01 )   E641-E642   2023年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Usefulness of the artificial intelligence-mediated virtual chromoendoscopy in peroral cholangioscopy. 査読 国際誌

    Ryosuke Sato, Kazuyuki Matsumoto, Hideaki Kinugasa, Daisuke Uchida, Shigeru Horiguchi, Hironari Kato, Motoyuki Otsuka

    Endoscopy   55 ( S 01 )   E971-E972   2023年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Cabozantinib inhibits HBV-RNA transcription by decreasing STAT3 binding to the enhancer region of cccDNA. 国際誌

    Kazuyoshi Funato, Nozomi Miyake, Kazuma Sekiba, Yu Miyakawa, Takahiro Seimiya, Chikako Shibata, Takahiro Kishikawa, Motoyuki Otsuka

    Hepatology communications   7 ( 11 )   2023年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: Precision medicine and customized therapeutics based on the features of each patient are important for maximizing therapeutic effects. Because most cases of HCC occur in the damaged liver through various etiologies, such as hepatitis virus infection, steatohepatitis, and autoimmune hepatitis, there should be a rationale for the choice of therapeutic options based on these etiologies. Although cabozantinib, an oral multikinase inhibitor, has demonstrated clinical effectiveness in advanced HCC, subgroup analyses showed a lower HR for death in HBV-related HCC. This study aimed to determine the therapeutic effects of cabozantinib in HBV-related HCC. METHODS: Using HBV infection models and gene knockout cells, we determined the crucial signaling axis responsible for the effects of cabozantinib on HBV. A chromatin immunoprecipitation assay was performed to determine the interaction between the signaling molecules and HBV DNA. Agonists and inhibitors were used for confirmation. RESULTS: Cabozantinib inhibited HBV replication through the HGF-mesenchymal-epithelial transition factor-signal transducer and activator of transcription 3 (MET-STAT3) signaling axis. The importance of STAT3 in viral replication has been confirmed using gene-edited STAT3 knockout cells. The chromatin immunoprecipitation assay revealed that the binding levels of phosphorylated STAT3 to enhancer region 1 of HBV covalently closed circular DNA were significantly increased by HGF stimulation. CONCLUSIONS: Cabozantinib has favorable therapeutic effects on HBV-related HCC because it inhibits HCC not only directly but also indirectly by means of inhibitory effects on HBV.

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  • Extracellular vesicle‑mediated RNA editing may underlie the heterogeneity and spread of hepatocellular carcinoma in human tissue and in vitro. 国際誌

    Chikako Shibata, Motoyuki Otsuka, Takayuki Shimizu, Takahiro Seimiya, Takahiro Kishikawa, Taku Aoki, Mitsuhiro Fujishiro

    Oncology reports   50 ( 5 )   2023年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Extracellular vesicles (EVs) produced by various cells, including tumor cells, carry biomolecules to neighboring cells. In hepatocellular carcinoma (HCC), adenosine to inosine RNA editing of antizyme inhibitor 1 (AZIN1), specifically regulated by adenosine deaminase acting on RNA‑1 (ADAR1), promotes carcinogenesis. The present study examined if EVs and ADAR1 in the EVs released from HCC cells are transferred to neighboring cells in co‑culture systems and reporter assay. Distribution of the ADAR1 expression in human tissues were examined by immunohistochemistry. EVs released from HCC cells containing ADAR1 were delivered to neighboring HCC cells and non‑cancerous hepatocytes. The increased ADAR1 protein levels resulted in serine to glycine substitution at residue 367 of AZIN1, which augmented transformation potential and increased aggressive behavior of cancer cells. In clinically resected samples, ADAR1 distribution was highly heterogeneous within the tumor specimen and denser in non‑cancerous tissue surrounding the HCC tissue. These observations suggested that ADAR1 protein may be delivered from HCC cells to neighboring cells via EVs and that EV‑mediated RNA editing may serve a pivotal role in determining HCC heterogeneity and spread.

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  • Cysts or necrotic components in pancreatic ductal adenocarcinoma is associated with the risk of EUS-FNA/B complications including needle tract seeding. 国際誌

    Hiroyuki Terasawa, Kazuyuki Matsumoto, Takehiro Tanaka, Takeshi Tomoda, Taiji Ogawa, Yuki Ishihara, Tatsuya Kikuchi, Taisuke Obata, Takashi Oda, Akihiro Matsumi, Kazuya Miyamoto, Kosaku Morimoto, Yuki Fujii, Tatsuhiro Yamazaki, Daisuke Uchida, Shigeru Horiguchi, Koichiro Tsutsumi, Hironari Kato, Motoyuki Otsuka

    Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.]   2023年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: EUS-FNA/B for pancreatic ductal adenocarcinoma (PDAC) is generally considered to be safe; however, while the incidence is low, there are occurrences of complications. Among these complications, there are serious ones like needle tract seeding (NTS), and it is not known than which types of tumors have the risks of EUS-FNA/B complications. This study aimed to evaluate the risk of EUS-FNA/B complications in patients with PDAC, focusing on morphological features. METHODS: Overall, 442 patients who underwent EUS-FNA/B for solid pancreatic masses between January 2018 and May 2022 in four institutions were retrospectively surveyed. Finally, 361 patients histopathologically diagnosed with PDAC were analyzed. Among these patients, 79 tumors with cysts or necrotic components were compared with 282 tumors without cysts or necrotic components. The incidence and risk of EUS-FNA/B complications including NTS were evaluated. RESULTS: There were 9 (2.4 %) of total EUS-FNA/B complications and 3 (0.8 %) of NTS. The incidence of total complication rate and NTS in tumors with cysts or necrotic components were significantly higher than in those without cysts or necrotic components (total complication 6.3 % vs. 1.4 %, p = 0.026, NTS 3.7 % vs. 0 %, p = 0.01). The transgastric route of puncture (OR: 93.3, 95 % CI: 3.81-2284.23) and the existence of cysts or necrotic components (OR: 7.3, 95 % CI: 1.47-36.19) were risk factors for EUS-FNA/B complications identified by the multivariate analysis. CONCLUSIONS: We should pay attention to the risks of EUS-FNA/B complications, including NTS, when the tumor has cysts or necrotic components.

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  • Optimal Bowel Preparation Method to Visualize the Distal Ileum via Small Bowel Capsule Endoscopy. 国際誌

    Daisuke Kametaka, Mamoru Ito, Seiji Kawano, Shuhei Ishiyama, Akiko Fujiwara, Junichirou Nasu, Masao Yoshioka, Junji Shiode, Kazuhide Yamamoto, Masaya Iwamuro, Yoshiro Kawahara, Hiroyuki Okada, Motoyuki Otsuka

    Diagnostics (Basel, Switzerland)   13 ( 20 )   2023年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Small bowel capsule endoscopy (SBCE) is a convenient and minimally invasive method widely used to evaluate the small intestine. However, especially in the distal ileum, visualization of the intestinal mucosa is frequently hampered by the remaining intestinal contents, making it difficult to detect critical lesions. Although several studies have reported on the efficacy of bowel preparation before SBCE, no standardized protocol has been established. Herein, we determined the optimal preparation method for better visualization of the distal ileum using SBCE. We retrospectively analyzed 259 consecutive patients who had undergone SBCE between July 2009 and December 2019, divided into three groups: Group A (no preparation except overnight fasting), Group B (ingestion of 1-2 L polyethylene glycol 4 h before colonoscopy after overnight fasting and performing SBCE immediately after colonoscopy), and Group C (ingestion of 0.9 L magnesium citrate [MC] before SBCE after overnight fasting). The visibility of the intestinal mucosa in the first 10 min and at the last 10 min during the period of observation of the distal ileum was examined using a scoring system and compared. The visibility of the images captured by SBCE was assessed based on the scoring of the degree of bile/chyme staining, residual fluid and debris, brightness, bubble reduction, and visualized mucosa. The status of intestinal collapse was also assessed. In the first 10 min of observation of the distal ileum, no significant differences were detected among the groups. In the last 10 min, significantly better images were acquired in Group C in terms of bile/chyme staining, brightness, bubble reduction, and visualized mucosa. Bowel preparation using a low-dose MC solution 2 h before SBCE provided significantly higher-quality images of the distal ileum. Further optimization, such as the timing of initiating the preparation, is necessary to determine the optimal regimen for bowel preparation prior to SBCE.

    DOI: 10.3390/diagnostics13203269

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  • Idiopathic Gastric Antral Ulcers.

    Masaya Iwamuro, Takehiro Tanaka, Seiji Kawano, Yoshiro Kawahara, Motoyuki Otsuka

    Internal medicine (Tokyo, Japan)   2023年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A Japanese woman presented with gastric antral ulcers accompanied by erosion and edema, demonstrating a chronic pattern of improvement and recurrence for more than six years. The patient had no relevant treatment history, and Helicobacter pylori infection was ruled out. Other potential etiologies contributing to gastric ulcers were eliminated on the basis of endoscopic biopsy and blood laboratory findings. Consequently, the patient was diagnosed with idiopathic gastric antral ulcer. This disease is often overlooked, and the chronological endoscopic images provided in this report can be used as a reference.

    DOI: 10.2169/internalmedicine.2554-23

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  • Endoscopic Manifestations and Clinical Characteristics of Localized Gastric Light-Chain Amyloidosis.

    Masaya Iwamuro, Shouichi Tanaka, Tatsuya Toyokawa, Mamoru Nishimura, Takao Tsuzuki, Koji Miyahara, Shin Negishi, Shogen Ohya, Takehiro Tanaka, Motoyuki Otsuka

    Acta medica Okayama   77 ( 5 )   545 - 552   2023年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    To determine the endoscopic and clinical features of localized gastric amyloid light-chain (AL) amyloidosis, we retrospectively examined the characteristics of nine patients (eight men and one woman) encountered by the hospitals in our network. Lesions were predominantly flat and depressed with surface vascular dilatation (n=5); others were characterized by subepithelial lesions (n=2), mucosal color change (n=1), and a mass-like morphology with swollen mucosal folds (n=1). Colonoscopy (n=7), video capsule enteroscopy (n=2), serum (n=5) and urine immunoelectrophoresis (n=4), and bone marrow examination (n=3) were performed to exclude involvement of organs other than the stomach. As treatment for gastric lesions of AL amyloidosis, one patient each underwent endoscopic submucosal dissection (n=1) and argon plasma coagulation (n=1), while the remaining seven patients underwent no specific treatment. During a mean follow-up of 4.2 years, one patient died 3.2 years after diagnosis, but the cause of death, which occurred in another hospital, was unknown. The remaining eight patients were alive at the last visit. In conclusion, although localized gastric AL amyloidosis can show various macroscopic features on esophagogastroduodenoscopy, flat, depressed lesions with vascular dilatation on the surface are predominant.

    DOI: 10.18926/AMO/65978

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  • The efficacy of non-anesthesiologist-administered propofol sedation with a target-controlled infusion system during double-balloon endoscopic retrograde cholangiopancreatography. 国際誌

    Kazuya Miyamoto, Kazuyuki Matsumoto, Taisuke Obata, Ryosuke Sato, Akihiro Matsumi, Kosaku Morimoto, Taiji Ogawa, Hiroyuki Terasawa, Yuki Fujii, Tatsuhiro Yamazaki, Daisuke Uchida, Shigeru Horiguchi, Koichiro Tsutsumi, Hironari Kato, Motoyuki Otsuka

    BMC gastroenterology   23 ( 1 )   296 - 296   2023年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: The sedation method used during double-balloon endoscopic retrograde cholangiopancreatography (DB-ERCP) differs among countries and/or facilities, and there is no established method. This study aimed to evaluate the efficacy of non-anesthesiologist-administered propofol (NAAP) sedation using a target-controlled infusion (TCI) system during DB-ERCP. METHODS: This retrospective study was conducted between May 2017 and December 2020 at an academic center. One hundred and fifty-six consecutive patients who underwent DB-ERCP were sedated by gastroenterologists using diazepam (n = 77) or propofol with a TCI system (n = 79), depending on the period. The primary endpoint was a comparison of poor sedation rates between the two groups. Poor sedation was defined as a condition requiring the use of other sedative agents or discontinuation of the procedure. Secondary endpoints were sedation-related adverse events and risk factors for poor sedation. RESULTS: Poor sedation occurred significantly more often in the diazepam sedation group (diazepam sedation, n = 12 [16%] vs. propofol sedation, n = 1 [1%]; P = 0.001). Vigorous body movements (3 or 4) (diazepam sedation, n = 40 [52%] vs. propofol sedation, n = 28 [35%]; P = 0.038) and hypoxemia (< 85%) (diazepam sedation, n = 7 [9%] vs. propofol sedation, n = 1 [1%]; P = 0.027) occurred significantly more often in the diazepam sedation group. In the multivariate analysis, age < 70 years old (OR, 10.26; 95% CI, 1.57-66.98; P = 0.015), BMI ≥ 25 kg/m2 (OR, 11.96; 95% CI, 1.67-85.69; P = 0.014), and propofol sedation (OR, 0.06; 95% CI, 0.01-0.58; P = 0.015) were associated factors for poor sedation. CONCLUSIONS: NAAP sedation with the TCI system during DB-ERCP was safer and more effective than diazepam sedation.

    DOI: 10.1186/s12876-023-02936-8

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  • Biological Roles of Hepatitis B Viral X Protein in the Viral Replication and Hepatocarcinogenesis.

    Motoyuki Otsuka

    Acta medica Okayama   77 ( 4 )   341 - 345   2023年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Hepatitis B virus is a pathogenic virus that infects 300 million people worldwide and causes chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Hepatitis B virus encodes four proteins. Among them, the HBx protein plays a central role in the HBV pathogenesis. Because the HBx protein is considered to play a central role in the induction of viral replication and hepatocarcinogenesis, the regulation of its function could be a key factor in the development of new interventions against hepatitis B. In this review, HBx protein-related viral replication and hepatocarcinogenesis mechanisms are described, with a focus on the recently reported viral replication mechanisms related to degradation of the Smc5/6 protein complex. We also discuss our recent discovery of a compound that inhibits HBx protein-induced degradation of the Smc5/6 protein complex, and that exerts inhibitory effects on both viral replication and hepatocarcinogenesis. Finally, prospects for future research on the HBx protein are described.

    DOI: 10.18926/AMO/65739

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  • 【胃良性疾患の近未来】[薬剤関連疾患]White globe appearance(WGA)

    岩室 雅也, 田中 健大, 大塚 基之

    消化器内視鏡   35 ( 8 )   1072 - 1074   2023年8月

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    記述言語:日本語   出版者・発行元:(株)東京医学社  

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  • Oxidative stress-related markers as prognostic factors for patients with primary sclerosing cholangitis in Japan. 査読 国際誌

    Atsushi Oyama, Akinobu Takaki, Takuya Adachi, Nozomu Wada, Yasuto Takeuchi, Hideki Onishi, Hidenori Shiraha, Hiroyuki Okada, Motoyuki Otsuka

    Hepatology international   17 ( 5 )   1215 - 1224   2023年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND/PURPOSE: Primary sclerosing cholangitis (PSC) is a rare chronic liver disease. The mechanisms and prediction of PSC progression are unclear. Recent investigations have shown that general conditions, such as oxidative stress, affect the course of chronic diseases. We investigated the clinical course and oxidative stress-related condition of PSC to determine prognostic factors. METHODS: We recruited 58 patients with PSC (mean age; 37.4 years, mean observation period; 1382 days) who visited our department from 2003 to 2021. Clinical characteristics were investigated to define prognostic factors. Oxidative stress status was evaluated using two types of markers: an oxidative stress marker (serum reactive oxygen metabolite; dROM) and an antioxidant marker (serum OXY adsorbent test; OXY). RESULTS: The revised Mayo risk, Child-Pugh, model for end-stage liver disease-sodium (MELD-Na) scores or fibrosis-related FIB-4 index significantly predicted poor overall survival. High intestinal immunoglobulin A (IgA) levels predicted poor survival. Among patients with high and intermediate revised Mayo risk scores, those with physiologically high dROM levels showed better survival than those with lower dROM levels. In this population, dROM was negatively correlated with AST and IgA, which are both correlated with survival. CONCLUSIONS: High and intermediate revised Mayo risk score group predicted a poor clinical course in PSC. Additionally, the Child-Pugh score, MELD-Na score, FIB-4 index, and serum IgA were significantly correlated with survival. In patients with high and intermediate revised Mayo risk scores, physiologically high oxidative stress status correlated with low IgA levels and a good prognosis.

    DOI: 10.1007/s12072-023-10557-2

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  • Review of oral and pharyngolaryngeal benign lesions detected during esophagogastroduodenoscopy. 査読 国際誌

    Masaya Iwamuro, Kenta Hamada, Seiji Kawano, Yoshiro Kawahara, Motoyuki Otsuka

    World journal of gastrointestinal endoscopy   15 ( 7 )   496 - 509   2023年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Recent advancements in endoscopy equipment have facilitated endoscopists' detection of neoplasms in the oral cavity and pharyngolaryngeal regions. In particular, image-enhanced endoscopy using narrow band imaging or blue laser imaging play an integral role in the endoscopic diagnosis of oral and pharyngolaryngeal cancers. Despite these advancements, limited studies have focused on benign lesions that can be observed during esophagogastroduodenoscopy in the oral and pharyngolaryngeal regions. Therefore, this mini-review aimed to provide essential information on such benign lesions, along with representative endoscopic images of dental caries, cleft palate, palatal torus, bifid uvula, compression by cervical osteophytes, tonsil hyperplasia, black hairy tongue, oral candidiasis, oral and pharyngolaryngeal ulcers, pharyngeal melanosis, oral tattoos associated with dental alloys, retention cysts, papilloma, radiation-induced changes, skin flaps, vocal cord paresis, and vocal fold leukoplakia. Whilst it is imperative to seek consultation from otolaryngologists or dentists in instances where the diagnosis cannot be definitively ascertained by endoscopists, the merits of attaining foundational expertise pertaining to oral and pharyngolaryngeal lesions are unequivocal. This article will be a valuable resource for endoscopists seeking to enhance their understanding of oral and pharyngolaryngeal lesions.

    DOI: 10.4253/wjge.v15.i7.496

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  • 結節を有するIPMNの良悪性診断における新規TIC解析プログラムを用いた造影EUSの有用性

    宮本 和也, 松本 和幸, 内田 大輔, 小幡 泰介, 佐藤 亮介, 織田 崇志, 菊池 達也, 松三 明宏, 森本 光作, 寺澤 裕之, 藤井 佑樹, 山崎 辰洋, 堀口 繁, 堤 康一郎, 加藤 博也, 大塚 基之

    膵臓   38 ( 3 )   A345 - A345   2023年7月

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    記述言語:日本語   出版者・発行元:(一社)日本膵臓学会  

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  • 当院における術後膵空腸吻合部狭窄に対する内視鏡治療成績の検討

    森本 光作, 山崎 辰洋, 小幡 泰介, 佐藤 亮介, 織田 崇志, 菊池 達也, 松三 明宏, 宮本 和也, 寺澤 裕之, 藤井 佑樹, 内田 大輔, 松本 和幸, 堀口 繁, 堤 康一郎, 加藤 博也, 大塚 基之

    膵臓   38 ( 3 )   A337 - A337   2023年7月

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    記述言語:日本語   出版者・発行元:(一社)日本膵臓学会  

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  • 高齢者における膵癌術前化学療法の有効性と安全性の検討

    藤井 佑樹, 堀口 繁, 佐藤 亮介, 小幡 泰介, 松三 明宏, 宮本 和也, 森本 光作, 寺澤 裕之, 山崎 辰洋, 内田 大輔, 松本 和幸, 堤 康一郎, 加藤 博也, 大塚 基之

    膵臓   38 ( 3 )   A316 - A316   2023年7月

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    記述言語:日本語   出版者・発行元:(一社)日本膵臓学会  

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  • Endoscopic evaluation by the Kyoto classification of gastritis combined with serum anti-Helicobacter pylori antibody testing reliably risk-stratifies subjects in a population-based gastric cancer screening program. 査読

    Ryosuke Hirai, Mami Hirai, Motoyuki Otsuka, Toshiharu Mitsuhashi, Yuichi Shimodate, Hirokazu Mouri, Kazuhiro Matsueda, Hiroshi Yamamoto, Motowo Mizuno

    Journal of gastroenterology   58 ( 9 )   848 - 855   2023年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: We previously demonstrated that the Kyoto classification of gastritis was useful for judging the status of Helicobacter pylori infection in a population-based screening program, and that adding H. pylori antibody test improved its accuracy (UMIN000028629). Here, we tested whether our endoscopic diagnosis of H. pylori infection status reliably estimated gastric cancer risk in the program. METHODS: Data were collected from1345 subjects who underwent endoscopic follow-up 4 years after the end of the registration. We analyzed the association of three diagnostic methods of H. pylori infection with gastric cancer detection: (1) endoscopic diagnosis based on the Kyoto classification of gastritis; (2) serum diagnosis according to the ABC method (H. pylori antibody and pepsinogen I and II); and (3) endoscopic diagnosis together with H. pylori antibody test. RESULTS: During the follow-up, 19 cases of gastric cancer were detected. By Kaplan-Meier analysis, the detection rates of cancer were significantly higher in the past or current H. pylori infection groups than in the never-infected group with all 3 methods. By the Cox proportional hazards model, the hazard ratio for cancer detection was highest in evaluation with the combined endoscopic diagnosis and the antibody test (method 3; hazard ratio 22.6, 95% confidence interval 2.99-171) among the three methods (the endoscopic diagnosis (method 1); 11.3, 2.58-49.8, and the ABC method (method 2); 7.52, 2.49-22.7). CONCLUSIONS: Endoscopic evaluation of H. pylori status with the Kyoto classification of gastritis, especially combined with serum anti-Helicobacter pylori antibody testing, reliably risk-stratified subjects in a population-based gastric cancer screening program.

    DOI: 10.1007/s00535-023-02010-w

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  • Update in Molecular Aspects and Diagnosis of Autoimmune Gastritis. 査読 国際誌

    Masaya Iwamuro, Takehiro Tanaka, Motoyuki Otsuka

    Current issues in molecular biology   45 ( 7 )   5263 - 5275   2023年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Recent studies have advanced our understanding of the pathophysiology of autoimmune gastritis, particularly its molecular aspects. The most noteworthy recent advancement lies in the identification of several candidate genes implicated in the pathogenesis of pernicious anemia through genome-wide association studies. These genes include PTPN22, PNPT1, HLA-DQB1, and IL2RA. Recent studies have also directed attention towards other genes such as ATP4A, ATP4B, AIRE, SLC26A7, SLC26A9, and BACH2 polymorphism. In-depth investigations have been conducted on lymphocytes and cytokines, including T helper 17 cells, interleukin (IL)-17A, IL-17E, IL-17F, IL-21, IL-19, tumor necrosis factor-α, IL-15, transforming growth factor-β1, IL-13, and diminished levels of IL-27. Animal studies have explored the involvement of roseolovirus and H. pylori in relation to the onset of the disease and the process of carcinogenesis, respectively. Recent studies have comprehensively examined the involvement of autoantibodies, serum pepsinogen, and esophagogastroduodenoscopy in the diagnosis of autoimmune gastritis. The current focus lies on individuals demonstrating atypical presentations of the disease, including those diagnosed in childhood, those yielding negative results for autoantibodies, and those lacking the typical endoscopic characteristics of mucosal atrophy. Here, we discuss the recent developments in this field, focusing on genetic predisposition, epigenetic modifications, lymphocytes, cytokines, oxidative stress, infectious agents, proteins, microRNAs, autoantibodies, serum pepsinogen, gastrin, esophagogastroduodenoscopy and microscopic findings, and the risk of gastric neoplasm.

    DOI: 10.3390/cimb45070334

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  • 長期経過を追えた膵Intraductal oncocytic papillary neoplasm(IOPN)の1例

    藤井 佑樹, 佐藤 亮介, 小幡 泰介, 松三 明宏, 宮本 和也, 森本 光作, 寺澤 裕之, 山崎 辰洋, 内田 大輔, 松本 和幸, 堀口 繁, 堤 康一郎, 加藤 博也, 大塚 基之

    日本消化器病学会中国支部例会プログラム・抄録集   119回   67 - 67   2023年6月

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    記述言語:日本語   出版者・発行元:日本消化器病学会-中国支部  

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  • 進行胆道癌に対するゲムシタビン・シスプラチン・S-1併用療法の治療成績についての検討

    小幡 泰介, 松本 和幸, 佐藤 亮介, 菊池 達也, 織田 崇志, 松三 明宏, 宮本 和也, 森本 光作, 寺澤 裕之, 藤井 佑樹, 山崎 辰洋, 内田 大輔, 堀口 繁, 堤 康一郎, 加藤 博也, 大塚 基之

    日本消化器病学会中国支部例会プログラム・抄録集   119回   65 - 65   2023年6月

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    記述言語:日本語   出版者・発行元:日本消化器病学会-中国支部  

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  • 肝内結石に対して内視鏡用イントロデューサーEndoSheatherが有用であった1例

    佐藤 亮介, 藤井 佑樹, 小幡 泰介, 松三 明宏, 宮本 和也, 森本 光作, 寺澤 裕之, 山崎 辰洋, 内田 大輔, 松本 和幸, 堤 康一郎, 堀口 繁, 加藤 博也, 大塚 基之

    日本消化器内視鏡学会中国支部例会   130回   83 - 83   2023年6月

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    記述言語:日本語   出版者・発行元:日本消化器内視鏡学会-中国支部  

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  • 悪性輸入脚症候群に対して超音波内視鏡下消化管ドレナージが有効であった1例

    森本 光作, 松本 和幸, 小幡 泰介, 佐藤 亮介, 織田 崇志, 菊池 達也, 松三 明宏, 宮本 和也, 寺澤 裕之, 藤井 佑樹, 山崎 辰洋, 内田 大輔, 堀口 繁, 堤 康一郎, 加藤 博也, 大塚 基之

    日本消化器内視鏡学会中国支部例会   130回   83 - 83   2023年6月

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    記述言語:日本語   出版者・発行元:日本消化器内視鏡学会-中国支部  

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  • Collagenous Colitis in a Patient With Gastric Cancer Who Underwent Chemotherapy. 査読 国際誌

    Masaya Iwamuro, Takehiro Tanaka, Shunsuke Kagawa, Shoko Inoo, Motoyuki Otsuka

    Cureus   15 ( 5 )   e39466   2023年5月

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    記述言語:英語  

    Herein, we present a case of collagenous colitis in a patient who underwent chemotherapy for gastric cancer, comprising five cycles of S-1 plus oxaliplatin and trastuzumab, followed by five cycles of paclitaxel and ramucirumab and seven cycles of nivolumab. The subsequent initiation of trastuzumab deruxtecan chemotherapy led to the development of grade 3 diarrhea after the second cycle of treatment. Collagenous colitis was diagnosed via colonoscopy and biopsy. The patient's diarrhea improved following the cessation of lansoprazole. This case highlights the importance of considering collagenous colitis as a differential diagnosis, in addition to chemotherapy-induced colitis and immune-related adverse event (irAE) colitis, in patients with similar clinical presentations.

    DOI: 10.7759/cureus.39466

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  • 選択的胆管seekingのためのデバイス選択

    小幡 泰介, 内田 大輔, 加藤 博也, 佐藤 亮介, 松三 明宏, 宮本 和也, 森本 光作, 寺澤 裕之, 藤井 佑樹, 山崎 辰洋, 松本 和幸, 堀口 繁, 堤 康一郎, 大塚 基之

    Gastroenterological Endoscopy   65 ( Suppl.1 )   971 - 971   2023年4月

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    記述言語:日本語   出版者・発行元:(一社)日本消化器内視鏡学会  

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  • Optimal liver drainage rate for survival in patients with unresectable malignant hilar biliary obstruction using 3D-image volume analyzer. 国際誌

    Kosaku Morimoto, Kazuyuki Matsumoto, Taisuke Obata, Takashi Oda, Kazuya Miyamoto, Akihiro Matsumi, Hiroyuki Terasawa, Yuki Fujii, Tatsuhiro Yamazaki, Shigeru Horiguchi, Koichiro Tsutsumi, Hironari Kato, Motoyuki Otsuka

    Therapeutic advances in gastroenterology   16   17562848231206980 - 17562848231206980   2023年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: Drainage exceeding 50% of total liver volume is a beneficial prognostic factor in patients with unresectable malignant hilar biliary obstruction (UMHBO). However, it is unclear what threshold percentage of total liver volume drained ('liver drainage rate') significantly improves survival in patients with UMHBO who received systemic chemotherapy. OBJECTIVES: We aimed to assess the optimal liver drainage rate that improves survival in patients with UMHBO receiving chemotherapy using a three-dimensional (3D)-image volume analyzer. DESIGN: This study was a single-center retrospective cohort study. METHODS: Data from 90 patients with UMHBO who received chemotherapy after endoscopic biliary drainage using metal stents at Okayama University Hospital from January 2003 to December 2020 were reviewed. The liver drainage rate was calculated by dividing the drained liver volume by the total liver volume using a 3D-image volume analyzer. The primary endpoint was overall survival by liver drainage rate. The secondary endpoints were time to recurrent biliary obstruction (TRBO) and prognostic factors. RESULTS: The median total liver volume was 1172 (range: 673-2032) mL, and the median liver drainage rate was 83% (range: 50-100). Overall survival was 376 (95% CI: 271-450) days, and patients with >80% drainage (n = 67) had significantly longer survival than those with <80% drainage (n = 23) (450 days versus 224 days, p = 0.0033, log-rank test). TRBO was 201 (95% CI: 155-327) days and did not differ significantly by liver drainage rate. Multivariate Cox proportional hazards regression analysis revealed >80% liver drainage [hazard ratio (HR): 0.35, 95% CI: 0.20-0.62, p = 0.0003] and hilar cholangiocarcinoma (HR: 0.30, 95% CI: 0.17-0.50, p < 0.0001) as significant prognostic factors. CONCLUSION: In patients with UMHBO scheduled for chemotherapy, >80% drainage is associated with improved survival. Further prospective multicenter studies are needed to verify the results of this study. TRAIL REGISTRATION: Okayama University Hospital, IRB number: 2108-011.

    DOI: 10.1177/17562848231206980

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  • Smaller extracellular vesicles are released from pancreatic cancer cells by the alteration of the lipid composition under low glucose conditions. 査読 国際誌

    Chikako Shibata, Motoyuki Otsuka, Takahiro Seimiya, Kazunaga Ishigaki, Yu Miyakawa, Takahiro Kishikawa, Mitsuhiro Fujishiro

    Biochemical and biophysical research communications   637   314 - 321   2022年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Extracellular vesicles (EVs) released from cells into the blood facilitate intercellular communication and serve as new biomarkers to understand the pathophysiology of several conditions. Although the importance of the cargo inside EVs has been extensively studied, the sizes of EVs that vary with different types of cancers are relatively poorly explored. Here, we show that pancreatic cancer cell-derived EVs are significantly smaller than non-cancer cell-derived EVs. The smaller size distribution of these EVs was confirmed by specifically isolating and examining tumor-derived EVs from the heterogeneous EV population isolated from the sera of patients with pancreatic ductal adenocarcinoma. In vitro analyses mimicking tumor microenvironment conditions revealed that low glucose conditions reduced the size distribution and increased the level of unsaturated fatty acids in the tumor-derived EVs. Because the lipid composition defines the fluidity of the membrane, the results suggest that the alterations in the size of EVs could be due to the alteration of the fluidity and stability of the membrane covering the EVs. Furthermore, the uptake of smaller EVs by recipient cells was increased, which may lead to enhanced functional results. These results provide fundamental insights into the factors defining the size of EVs, which may be important for developing cancer screening methods and understanding cancer-related pathophysiology.

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  • HNF1B-driven three-dimensional chromatin structure for molecular classification in pancreatic cancers. 査読 国際誌

    Hiroyuki Kato, Keisuke Tateishi, Dosuke Iwadate, Keisuke Yamamoto, Hiroaki Fujiwara, Takuma Nakatsuka, Yotaro Kudo, Yoku Hayakawa, Hideaki Ijichi, Motoyuki Otsuka, Takahiro Kishikawa, Ryota Takahashi, Koji Miyabayashi, Yousuke Nakai, Yoshihiro Hirata, Atsushi Toyoda, Shinichi Morishita, Mitsuhiro Fujishiro

    Cancer science   114 ( 4 )   1672 - 1685   2022年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The molecular subtypes of pancreatic cancer (PC), either classical/progenitor-like or basal/squamous-like, are currently a major topic of research because of their direct association with clinical outcomes. Some transcription factors (TFs) have been reported to be associated with these subtypes. However, the mechanisms by which these molecular signatures of PCs are established remain unknown. Epigenetic regulatory processes, supported by dynamic changes in the chromatin structure, are essential for transcriptional profiles. Previously, we reported the importance of open chromatin profiles in the biological features and transcriptional status of PCs. Here, we aimed to analyze the relationships between three-dimensional (3D) genome structures and the molecular subtypes of human PCs using Hi-C analysis. We observed a correlation of the specific elements of 3D genome modules, including compartments, topologically associating domains, and enhancer-promoter loops, with the expression of related genes. We focused on HNF1B, a TF that is implicated in the progenitor subtype. Forced expression of HNF1B in squamous-type PC organoids induced the upregulation and downregulation of genes associated with progenitor and squamous subtypes, respectively. Long-range genomic interactions induced by HNF1B were accompanied by compartment modulation and H3K27ac redistribution. We also found that these HNF1B-induced changes in subtype-related gene expression required an intrinsically disordered region, suggesting a possible involvement of phase separation in compartment modulation. Thus, mapping of 3D structural changes induced by TFs, such as HNF1B, may become a useful resource for further understanding the molecular features of PCs.

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  • The RNA-Binding Protein ELAVL1 Regulates Hepatitis B Virus Replication and Growth of Hepatocellular Carcinoma Cells. 査読 国際誌

    Hiroaki Kanzaki, Tetsuhiro Chiba, Tatsuya Kaneko, Junjie Ao, Motoyasu Kan, Ryosuke Muroyama, Shingo Nakamoto, Tatsuo Kanda, Hitoshi Maruyama, Jun Kato, Yoh Zen, Ai Kotani, Kazuma Sekiba, Motoyuki Otsuka, Masayuki Ohtsuka, Naoya Kato

    International journal of molecular sciences   23 ( 14 )   2022年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Previous RNA immunoprecipitation followed by proteomic approaches successfully demonstrated that Embryonic Lethal, Abnormal Vision, Drosophila-Like 1 (ELAVL1) interacts with hepatitis B virus (HBV)-derived RNAs. Although ELAVL family proteins stabilize AU-rich element (ARE)-containing mRNAs, their role in HBV transcription remains unclear. This study conducted loss-of-function assays of ELAVL1 for inducible HBV-replicating HepAD38 cells and HBx-overexpressed HepG2 cells. In addition, clinicopathological analyses in primary hepatocellular carcinoma (HCC) surgical samples were also conducted. Lentivirus-mediated short hairpin RNA knockdown of ELAVL1 resulted in a decrease in both viral RNA transcription and production of viral proteins, including HBs and HBx, probably due to RNA stabilization by ELAVL1. Cell growth of HepAD38 cells was more significantly impaired in ELAVL1-knockdown than those in the control group, with or without HBV replication, indicating that ELAVL1 is involved in proliferation by factors other than HBV-derived RNAs. Immunohistochemical analyses of 77 paired HCC surgical specimens demonstrated that diffuse ELAVL1 expression was detected more frequently in HCC tissues (61.0%) than in non-tumor tissues (27.3%). In addition, the abundant expression of ELAVL1 tended to affect postoperative recurrence in HBV-related HCC patients. In conclusion, ELAVL1 contributes not only to HBV replication but also to HCC cell growth. It may be a potent therapeutic target for HBV-related HCC treatment.

    DOI: 10.3390/ijms23147878

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  • Hepatitis B virus-associated hepatocellular carcinoma with Smc5/6 complex deficiency is susceptible to PARP inhibitors. 査読 国際誌

    Kazuyoshi Funato, Motoyuki Otsuka, Kazuma Sekiba, Yu Miyakawa, Takahiro Seimiya, Chikako Shibata, Takahiro Kishikawa, Mitsuhiro Fujishiro

    Biochemical and biophysical research communications   607   89 - 95   2022年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DNA repair processes represent attractive synthetic lethal targets because many cancers exhibit impaired DNA repair pathways, which leads to dependence on specific repair proteins. The finding that poly (ADP-ribose) polymerase (PARP)-1 inhibitors are highly effective against cancers with deficient homologous recombination highlights the potential of this approach. In hepatitis B viral (HBV) infection, degradation of the structural maintenance of the chromosome 5/6 (Smc5/6) complex, which plays a key role in repairing double-stranded DNA breaks by homologous recombination, is induced by HBV regulatory protein X (HBx). Here, we hypothesized that a deficiency in the Smc5/6 complex in HBV-associated hepatocellular carcinoma (HCC) increases susceptibility to PARP inhibitors via a deficiency in homologous recombination. We confirmed impaired double-stranded DNA break repair in HBx-expressing HCC cells using a sensitive reporter to monitor homologous recombination. Treatment with a PARP inhibitor was significantly more effective against HBx-expressing HCC cells, and overexpression of Smc5/6 prevented these effects. Overall, our results suggest that homologous recombination deficiency in HBV-associated HCC leads to increased susceptibility to PARP inhibitors.

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  • Roles of circular RNAs in the pathogenesis and treatment of pancreatic cancer. 査読 国際誌

    Takahiro Seimiya, Motoyuki Otsuka, Mitsuhiro Fujishiro

    Frontiers in cell and developmental biology   10   1023332 - 1023332   2022年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Circular RNAs are single-stranded RNAs with a covalently closed structure formed by the process of back-splicing. Aberrant expression of circular RNAs contributes to the pathogenesis of a wide range of cancers. Pancreatic cancer is one of the most lethal cancers due to diagnostic difficulties and limited therapeutic options. Circular RNAs are emerging as novel diagnostic biomarkers and therapeutic targets for pancreatic cancer. Moreover, recent advances in the therapeutic application of engineered circular RNAs have provided a promising approach to overcoming pancreatic cancer. This review discusses the roles of circular RNAs in the pathogenesis of pancreatic cancer and in potential treatment applications and their usefulness as diagnostic biomarkers.

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  • Evidence-based clinical practice guidelines for nonalcoholic fatty liver disease/nonalcoholic steatohepatitis 2020. 国際誌

    Motoyuki Otsuka

    Hepatology research : the official journal of the Japan Society of Hepatology   51 ( 10 )   1013 - 1025   2021年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Nonalcoholic fatty liver disease (NAFLD) has become a serious public health issue not only in Western countries but also in Japan. Within the wide spectrum of NAFLD, nonalcoholic steatohepatitis (NASH) is a progressive form of disease that often develops into liver cirrhosis and increases the risk of hepatocellular carcinoma (HCC). While a definite diagnosis of NASH requires liver biopsy to confirm the presence of hepatocyte ballooning, hepatic fibrosis is the most important prognostic factor in NAFLD. With so many NAFLD patients, it is essential to have an effective screening method for NAFLD with hepatic fibrosis. As HCC with non-viral liver disease has increased markedly in Japan, effective screening and surveillance of HCC are also urgently needed. The most common death etiology in NAFLD patients is cardiovascular disease event. Gastroenterologists must, therefore, pay close attention to CVD when examining NAFLD patients. In the updated guidelines, we propose screening and follow-up methods for hepatic fibrosis, HCC, and CVD in NAFLD patients. Several drug trials are ongoing for NAFLD/NASH therapy, however, there is currently no specific drug therapy for NAFLD/NASH. In addition to vitamin E and thiazolidinedione derivatives, recent trials have focused on sodium glucose co-transporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP-1) analogues, and effective therapies are expected to be developed. These practical guidelines for NAFLD/NASH were established by the Japanese Society of Gastroenterology in conjunction with the Japan Society of Hepatology. Clinical evidence reported internationally between 1983 and October 2018 was collected, and each clinical and background question was evaluated using the Grades of Recommendation Assessment, Development and Evaluation (GRADE) system. This English summary pro- vides the core essentials of these clinical practice guidelines, which include the definition and concept, screening systems for hepatic fibrosis, HCC and CVD, and current therapies for NAFLD/NASH in Japan.

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  • Evidence-based clinical practice guidelines for nonalcoholic fatty liver disease/nonalcoholic steatohepatitis 2020.

    Motoyuki Otsuka

    Journal of gastroenterology   56 ( 11 )   951 - 963   2021年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Nonalcoholic fatty liver disease (NAFLD) has become a serious public health issue not only in Western countries but also in Japan. Within the wide spectrum of NAFLD, nonalcoholic steatohepatitis (NASH) is a progressive form of disease that often develops into liver cirrhosis and increases the risk of hepatocellular carcinoma (HCC). While a definite diagnosis of NASH requires liver biopsy to confirm the presence of hepatocyte ballooning, hepatic fibrosis is the most important prognostic factor in NAFLD. With so many NAFLD patients, it is essential to have an effective screening method for NAFLD with hepatic fibrosis. As HCC with non-viral liver disease has increased markedly in Japan, effective screening and surveillance of HCC are also urgently needed. The most common death etiology in NAFLD patients is cardiovascular disease (CVD) event. Gastroenterologists must, therefore, pay close attention to CVD when examining NAFLD patients. In the updated guidelines, we propose screening and follow-up methods for hepatic fibrosis, HCC, and CVD in NAFLD patients. Several drug trials are ongoing for NAFLD/NASH therapy, however, there is currently no specific drug therapy for NAFLD/NASH. In addition to vitamin E and thiazolidinedione derivatives, recent trials have focused on sodium glucose co-transporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP-1) analogues, and effective therapies are expected to be developed. These practical guidelines for NAFLD/NASH were established by the Japanese Society of Gastroenterology in conjunction with the Japan Society of Hepatology. Clinical evidence reported internationally between 1983 and October 2018 was collected, and each clinical and background question was evaluated using the Grades of Recommendation Assessment, Development and Evaluation (GRADE) system. This English summary provides the core essentials of these clinical practice guidelines, which include the definition and concept, screening systems for hepatic fibrosis, HCC and CVD, and current therapies for NAFLD/NASH in Japan.

    DOI: 10.1007/s00535-021-01796-x

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  • Humanized virus-suppressing factor inhibits hepatitis B virus infection by targeting viral cell entry. 査読 国際誌

    Yu Miyakawa, Motoyuki Otsuka, Kazuma Sekiba, Kazuyoshi Funato, Kazuhiko Koike

    Heliyon   7 ( 7 )   e07586   2021年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Although nucleos(t)ide analogs and interferons suppress hepatitis B virus (HBV) replication, they must be taken continuously and have a low response rate. Therefore, therapeutics for HBV with novel modes of action are needed. Humanized virus-suppressing factor (hzVSF) is a monoclonal antibody against vimentin that exhibits broad-spectrum antiviral activity. Here, hzVSF significantly inhibited HBV infection. Although hzVSF inhibited HBV RNA production, it did not affect viral transcription from minicircle DNA mimicking covalently closed circular DNA. Additionally, hzVSF did not inhibit viral protein or DNA release from infected cells. Rather, hzVSF inhibited the cell entry of viral preS1 peptides, possibly by altering intracellular vimentin localization, which is important for HBV cell entry. These results suggest that hzVSF has therapeutic potential for HBV infection with a novel mode of action.

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  • Potential of HBx Gene for Hepatocarcinogenesis in Noncirrhotic Liver. 査読 国際誌

    Kazuma Sekiba, Motoyuki Otsuka, Kazuhiko Koike

    Seminars in liver disease   41 ( 2 )   142 - 149   2021年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Current treatments for hepatitis B virus (HBV) using nucleos(t)ide analogs cannot eliminate the risk of hepatocellular carcinoma (HCC) development. As HBV-associated HCC can develop even in the absence of liver cirrhosis, HBV is regarded to possess direct oncogenic potential. HBV regulatory protein X (HBx) has been identified as a primary mediator of HBV-mediated hepatocarcinogenesis. A fragment of the HBV genome that contains the coding region of HBx is commonly integrated into the host genome, resulting in the production of aberrant proteins and subsequent hepatocarcinogenesis. Besides, HBx interferes with the host DNA or deoxyribonucleic acid damage repair pathways, signal transduction, epigenetic regulation of gene expression, and cancer immunity, thereby promoting carcinogenesis in the noncirrhotic liver. However, numerous molecules and pathways have been implicated in the development of HBx-associated HCC, suggesting that the mechanisms underlying HBx-mediated hepatocarcinogenesis remain to be elucidated.

    DOI: 10.1055/s-0041-1723033

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  • Post-treatment cell-free DNA as a predictive biomarker in molecular-targeted therapy of hepatocellular carcinoma. 査読

    Takuma Nakatsuka, Hayato Nakagawa, Yuki Hayata, Taijiro Wake, Tomoharu Yamada, Mizuki Nishibatake Kinoshita, Ryo Nakagomi, Masaya Sato, Tatsuya Minami, Koji Uchino, Kenichiro Enooku, Yotaro Kudo, Yasuo Tanaka, Takahiro Kishikawa, Motoyuki Otsuka, Ryosuke Tateishi, Kazuhiko Koike

    Journal of gastroenterology   56 ( 5 )   456 - 469   2021年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: Liquid biopsies, particularly those involving circulating tumor DNA (ctDNA), are rapidly emerging as a non-invasive alternative to tumor biopsies. However, clinical applications of ctDNA analysis in hepatocellular carcinoma (HCC) have not been fully elucidated. METHODS: We measured the amount of plasma-derived cell-free DNA (cfDNA) in HCC patients before (n = 100) and a few days after treatment (n = 87), including radiofrequency ablation, transarterial chemoembolization, and molecular-targeted agents (MTAs), and prospectively analyzed their associations with clinical parameters and prognosis. TERT promoter mutations in cfDNA were analyzed using droplet digital PCR. Furthermore, we performed a comprehensive mutational analysis of post-treatment cfDNA via targeted ultra-deep sequencing (22,000× coverage) in a panel of 275 cancer-related genes in selected patients. RESULTS: Plasma cfDNA levels increased significantly according to HCC clinical stage, and a high cfDNA level was independently associated with a poor prognosis. TERT promoter mutations were detected in 45% of all cases but were not associated with any clinical characteristics. cfDNA levels increased significantly a few days after treatment, and a greater increase in post-treatment cfDNA levels was associated with a greater therapeutic response to MTAs. The detection rate of TERT mutations increased to 57% using post-treatment cfDNA, suggesting that the ctDNA was enriched. Targeted ultra-deep sequencing using post-treatment cfDNA after administering lenvatinib successfully detected various gene mutations and obtained promising results in lenvatinib-responsive cases. CONCLUSIONS: Post-treatment cfDNA analysis may facilitate the construction of biomarkers for predicting MTA treatment effects.

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  • Mutant KRAS drives metabolic reprogramming and autophagic flux in premalignant pancreatic cells. 査読 国際誌

    Tatsunori Suzuki, Takahiro Kishikawa, Tatsuyuki Sato, Norihiko Takeda, Yuki Sugiura, Takahiro Seimiya, Kazuma Sekiba, Motoko Ohno, Takuma Iwata, Rei Ishibashi, Motoyuki Otsuka, Kazuhiko Koike

    Cancer gene therapy   29 ( 5 )   505 - 518   2021年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Mutational activation of the KRAS gene occurs in almost all pancreatic ductal adenocarcinoma (PDAC) and is the earliest molecular event in their carcinogenesis. Evidence has accumulated of the metabolic reprogramming in PDAC, such as amino acid homeostasis and autophagic flux. However, the biological effects of KRAS mutation on metabolic reprogramming at the earlier stages of PDAC carcinogenesis are unclear. Here we report dynamic metabolic reprogramming in immortalized human non-cancerous pancreatic ductal epithelial cells, in which a KRAS mutation was induced by gene-editing, which may mimic early pancreatic carcinogenesis. Similar to the cases of PDAC, KRAS gene mutation increased the dependency on glucose and glutamine for maintaining the intracellular redox balance. In addition, the intracellular levels of amino acids were significantly decreased because of active protein synthesis, and the cells required greater autophagic flux to maintain their viability. The lysosomal inhibitor chloroquine significantly inhibited cell proliferation. Therefore, metabolic reprogramming is an early event in carcinogenesis initiated by KRAS gene mutation, suggesting a rationale for the development of nutritional interventions that suppress or delay the development of PDAC.

    DOI: 10.1038/s41417-021-00326-4

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  • The biological role of metabolic reprogramming in pancreatic cancer 国際誌

    Tatsunori Suzuki, Motoyuki Otsuka, Takahiro Seimiya, Takuma Iwata, Takahiro Kishikawa, Kazuhiko Koike

    MedComm   1 ( 3 )   302 - 310   2020年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Wiley  

    Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease and highly resistant to all forms of therapy. PDAC cells reprogram their metabolism extensively to promote their survival and growth. Reflecting the vital role of altered metabolism, experimental and clinical trials targeting the rewired metabolism are currently underway. In this review, we summarize the vital role of metabolic reprogramming in the development of PDAC and the future of novel therapeutic applications.

    DOI: 10.1002/mco2.37

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  • The fatty-acid amide hydrolase inhibitor URB597 inhibits MICA/B shedding. 査読 国際誌

    Kazuma Sekiba, Motoyuki Otsuka, Takahiro Seimiya, Eri Tanaka, Kazuyoshi Funato, Yu Miyakawa, Kazuhiko Koike

    Scientific reports   10 ( 1 )   15556 - 15556   2020年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    MICA/B proteins are expressed on the surface of various types of stressed cells, including cancer cells. Cytotoxic lymphocytes expressing natural killer group 2D (NKG2D) receptor recognize MICA/B and eliminate the cells. However, cancer cells evade such immune recognition by inducing proteolytic shedding of MICA/B proteins. Therefore, preventing the shedding of MICA/B proteins could enhance antitumor immunity. Here, by screening a protease inhibitor library, we found that the fatty-acid amide hydrolase (FAAH) inhibitor, URB597, suppresses the shedding of MICA/B. URB597 significantly reduced the soluble MICA level in culture medium and increased the MICA level on the surface of cancer cells. The effect was indirect, being mediated by increased expression of tissue inhibitor of metalloproteinases 3 (TIMP3). Knockdown of TIMP3 expression reversed the effect of URB597, confirming that TIMP3 is required for the MICA shedding inhibition by URB597. In contrast, FAAH overexpression reduced TIMP3 expression and the cell-surface MICA level and increased the soluble MICA level. These results suggest that inhibition of FAAH could prevent human cancer cell evasion of immune-mediated clearance.

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  • Extracellular vesicles secreted by HBV-infected cells modulate HBV persistence in hydrodynamic HBV transfection mouse model. 査読 国際誌

    Masatoshi Kakizaki, Yuichiro Yamamoto, Motoyuki Otsuka, Kouichi Kitamura, Masatoshi Ito, Hideki Derek Kawai, Masamichi Muramatsu, Tatehiro Kagawa, Ai Kotani

    The Journal of biological chemistry   295 ( 35 )   12449 - 12460   2020年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Hepatitis B, a viral infection that affects the liver, is thought to affect over 257 million people worldwide, and long-term infection can lead to life-threatening issues such as cirrhosis or liver cancer. Chronic hepatitis B develops by the interaction between hepatitis B virus (HBV) and host immune response. However, questions of how HBV-infected cells thwart immune system defenses remain unanswered. Extracellular vesicles (EVs) are used for cellular communication, carrying cargoes such as RNAs, proteins, and lipids and delivering them intracellularly after being endocytosed by target cells. HBV-infected liver cells secrete several types of EVs into body fluids such as complete and incomplete virions, and exosomes. We previously demonstrated that monocytes that incorporated EVs moved to immunoregulatory phenotypes via up-regulation of PD-L1, an immunocheckpoint molecule, and down-regulation of CD69, a leukocyte activation molecule. In this study, we transfected mice with HBV using hydrodynamic injection and studied the effects of EVs secreted by HBV-infected liver cells. EVs secreted from cells with HBV replication strongly suppressed the immune response, inhibiting the eradication of HBV-replicating cells in the mice transfected with HBV. EVs were systemically incorporated in multiple organs, including liver, bone marrow (BM), and intestine. Intriguingly, the BM cells that incorporated EVs acquired intestinal tropism and the dendritic cell populations in the intestine increased. These findings suggest that the EVs secreted by HBV-infected liver cells exert immunosuppressive functions, and that an association between the liver, bone marrow, and intestinal tract exists through EVs secreted from HBV-infected cells.

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  • HBx increases EGFR expression by inhibiting miR129-5p function. 査読 国際誌

    Masanori Ochi, Motoyuki Otsuka, Reo Maruyama, Kazuhiko Koike

    Biochemical and biophysical research communications   529 ( 2 )   198 - 203   2020年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Despite the efficient suppression of hepatitis B virus (HBV) replication by nucelos(t)ide analogs, HBV RNA expression usually continues even during nucleots(t)ide analog therapy because episomal covalently closed circular DNA (ccDNA), which is the template for HBV RNA transcription, cannot be eliminated. Here, we found that the common sequences of all HBV RNAs and that encoding the X protein (HBx) have similarities with the sequences of a host cellular microRNA (miRNA), miR129-5p. HBx inhibits miR129-5p function, resulting in increased expression of ZBTB20, a target gene of miR129-5p. ZBTB20 activates transcription and increases cell-surface epidermal growth factor receptor (EGFR) levels, promoting the cell growth rate, and this effect was reversed through ZBTB20 knockdown. mir129-5p levels in Ago2-containing complexes were reduced by expression of HBx, suggesting that the viral RNA sequestered miR129-5p from Ago2-containing complexes. These results indicate the possibility that HBV RNA may maintain pathogenicity even through nucleos(t)ide analog therapy.

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  • B型肝炎根治を目指した創薬研究 宿主蛋白Smc5/6の発現回復によるHBV関連肝発癌制御の可能性

    關場 一磨, 大塚 基之, 小池 和彦

    日本消化器病学会雑誌   117 ( 臨増総会 )   A93 - A93   2020年7月

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    記述言語:日本語   出版者・発行元:(一財)日本消化器病学会  

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  • Emerging Roles of Exosomal Circular RNAs in Cancer. 査読 国際誌

    Takahiro Seimiya, Motoyuki Otsuka, Takuma Iwata, Chikako Shibata, Eri Tanaka, Tatsunori Suzuki, Kazuhiko Koike

    Frontiers in cell and developmental biology   8   568366 - 568366   2020年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Circular RNA (circRNA) is a type of non-coding RNA that forms a covalently closed continuous loop. The expression pattern of circRNA varies among cell types and tissues, and many circRNAs are aberrantly expressed in various cancers. Aberrantly expressed circRNAs have been shown to play crucial roles in carcinogenesis, functioning as microRNA sponges or new templates for protein translation. Recent research has shown that circRNAs are enriched in exosomes. Exosomes are secretory vesicles that mediate intercellular communication through the delivery of cargo, including proteins, lipids, DNA, and RNA. Exosome-mediated crosstalk between cancer cells and the tumor microenvironment promotes the epithelial-mesenchymal transition, angiogenesis, and immune escape, and thus may contribute to cancer invasion and metastasis. In this review, we discuss the biological functions of exosomal circRNAs and their significance in cancer progression. Additionally, we discuss the potential clinical applications of exosomal circRNAs as biomarkers and in cancer therapy.

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  • Deletion of Histone Methyltransferase G9a Suppresses Mutant Kras-driven Pancreatic Carcinogenesis

    HIROYUKI KATO, KEISUKE TATEISHI, HIROAKI FUJIWARA, HIDEAKI IJICHI, KEISUKE YAMAMOTO, TAKUMA NAKATSUKA, MIWAKO KAKIUCHI, MAKOTO SANO, YOTARO KUDO, YOKU HAYAKAWA, HAYATO NAKAGAWA, YASUO TANAKA, MOTOYUKI OTSUKA, YOSHIHIRO HIRATA, MAKOTO TACHIBANA, YOICHI SHINKAI, KAZUHIKO KOIKE

    Cancer Genomics - Proteomics   17 ( 6 )   695 - 705   2020年

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Anticancer Research USA Inc.  

    DOI: 10.21873/cgp.20224

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  • Improved liver function in patients with cirrhosis due to chronic hepatitis C virus who achieve sustained virologic response is not accompanied by increased liver volume. 査読 国際誌

    Taijiro Wake, Ryosuke Tateishi, Tsuyoshi Fukumoto, Ryo Nakagomi, Mizuki Nishibatake Kinoshita, Takuma Nakatsuka, Masaya Sato, Tatsuya Minami, Koji Uchino, Kenichiro Enooku, Hayato Nakagawa, Hidetaka Fujinaga, Yoshinari Asaoka, Yasuo Tanaka, Motoyuki Otsuka, Kazuhiko Koike

    PloS one   15 ( 4 )   e0231836   2020年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    BACKGROUND: Serum albumin level improves in patients with chronic hepatitis C virus (HCV) infection who achieve sustained virologic response (SVR) with antiviral therapy. However, it remains controversial whether liver volume increases along with SVR. METHODS: Patients with chronic HCV infection with a history of hepatocellular carcinoma (HCC) who achieved SVR with anti-HCV treatment from March 2003 to November 2017 were enrolled. Patients were followed up with periodic computed tomography (CT) scans to detect HCC recurrence. Patients who underwent treatment for HCC recurrence within 1 year after initiation of anti-HCV treatment were excluded. Laboratory data, including alanine aminotransferase (ALT) level, serum albumin level, and platelet count, were collected at baseline and timepoints after treatment initiation. Liver volume was evaluated at baseline and 24 and 48 weeks after treatment initiation using a CT volume analyzer. A linear mixed-effects model was applied to analyze the chronologic change in liver volume. The correlations between changes in ALT level, albumin level, and liver volume were also evaluated. RESULTS: Of 108 enrolled patients, 78 had cirrhosis. Serum albumin level continued to increase through 48 weeks after treatment initiation. A significant increase in liver volume was observed only in patients without cirrhosis (P = 0.005). There was a significant correlation between ALT level decrease and albumin level increase (P = 0.018). CONCLUSIONS: Improved liver albumin production with SVR was contributed by improved liver cell function rather than increased liver volume in patients with cirrhosis.

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  • Identifying Inhibitors of the HBx-DDB1 Interaction Using a Split Luciferase Assay System. 査読 国際誌

    Kazuma Sekiba, Motoyuki Otsuka, Kazuhiko Koike

    Journal of visualized experiments : JoVE   ( 154 )   2019年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    There is an urgent need for novel therapeutic agents for hepatitis B virus (HBV) infection. Although currently available nucleos(t)ide analogs potently inhibit viral replication, they have no direct effect on the expression of viral proteins transcribed from a viral covalently closed circular DNA (cccDNA). As high viral antigen load may play a role in this chronic and HBV-related carcinogenesis, the goal of HBV treatment is to eradicate viral proteins. HBV regulatory protein X (HBx) binds to the host DNA damage-binding protein 1 (DDB1) protein to degrade structural maintenance of chromosomes 5/6 (Smc5/6), resulting in activation of viral transcription from cccDNA. Here, using a split luciferase complementation assay system, we present a comprehensive compound screening system to identify inhibitors of the HBx-DDB1 interaction. Our protocol enables easy detection of interaction dynamics in real time within living cells. This technique may become a key assay to discover novel therapeutic agents for treatment of HBV infection.

    DOI: 10.3791/60652

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  • Detection of circulating colorectal cancer cells by a custom microfluid system before and after endoscopic metallic stent placement. 査読 国際誌

    Rei Ishibashi, Shuntaro Yoshida, Nariaki Odawara, Takahiro Kishikawa, Ryo Kondo, Ayako Nakada, Ryunosuke Hakuta, Naminatsu Takahara, Eri Tanaka, Kazuma Sekiba, Takahiro Seimiya, Takashi Ohnaga, Motoyuki Otsuka, Kazuhiko Koike

    Oncology letters   18 ( 6 )   6397 - 6404   2019年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Although the detection of circulating tumor cells (CTCs) should be crucial for future personalized medicine, no efficient and flexible methods have been established. The current study established a polymeric custom-made chip for capturing CTCs with a high efficiency and flexibility. As an example of clinical application, the effects of self-expandable metallic stent (SEMS) placement on the release of cancer cells into the blood of patients with colorectal cancer and bowel obstruction were analyzed. This was assessed as the placement of SEMS may cause mechanical damage and physical force to malignant tissue, increasing the risk of cancer cell release into the bloodstream. The present study examined the number of CTCs using a custom-made chip, before, at 24 h after and at 4 days after SEMS placement in patients with colorectal cancer. The results revealed that, among the 13 patients examined, the number of CTCs was increased in three cases at 24 h after SEMS placement. However, this increase was temporary. The number of CTCs also decreased at 4 days after stent placement in most cases. The CTC chip of the current study detected the number of CD133-positive cancer stem-like cells, which did not change, even in the patient whose total number of CTCs temporarily increased. The results indicated that this custom-made microfluid system can efficiently and flexibly detect CTCs, demonstrating its potential for obtaining information during the management of patients with cancer.

    DOI: 10.3892/ol.2019.11047

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  • Inhibition of HBV Transcription From cccDNA With Nitazoxanide by Targeting the HBx-DDB1 Interaction. 査読 国際誌

    Kazuma Sekiba, Motoyuki Otsuka, Motoko Ohno, Mari Yamagami, Takahiro Kishikawa, Tatsunori Suzuki, Rei Ishibashi, Takahiro Seimiya, Eri Tanaka, Kazuhiko Koike

    Cellular and molecular gastroenterology and hepatology   7 ( 2 )   297 - 312   2019年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier {BV}  

    BACKGROUND & AIMS: Hepatitis B virus (HBV) infection is a major health concern worldwide. Although currently used nucleos(t)ide analogs efficiently inhibit viral replication, viral proteins transcribed from the episomal viral covalently closed circular DNA (cccDNA) minichromosome continue to be expressed long-term. Because high viral RNA or antigen loads may play a biological role during this chronicity, the elimination of viral products is an ultimate goal of HBV treatment. HBV regulatory protein X (HBx) was recently found to promote transcription of cccDNA with degradation of Smc5/6 through the interaction of HBx with the host protein DDB1. Here, this protein-protein interaction was considered as a new molecular target of HBV treatment. METHODS: To identify candidate compounds that target the HBx-DDB1 interaction, a newly constructed split luciferase assay system was applied to comprehensive compound screening. The effects of the identified compounds on HBV transcription and cccDNA maintenance were determined using HBV minicircle DNA, which mimics HBV cccDNA, and the natural HBV infection model of human primary hepatocytes. RESULTS: We show that nitazoxanide (NTZ), a thiazolide anti-infective agent that has been approved by the FDA for protozoan enteritis, efficiently inhibits the HBx-DDB1 protein interaction. NTZ significantly restores Smc5 protein levels and suppresses viral transcription and viral protein production in the HBV minicircle system and in human primary hepatocytes naturally infected with HBV. CONCLUSIONS: These results indicate that NTZ, which targets an HBV-related viral-host protein interaction, may be a promising new therapeutic agent and a step toward a functional HBV cure.

    DOI: 10.1016/j.jcmgh.2018.10.010

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  • Expression of circular RNA CDR1‑AS in colon cancer cells increases cell surface PD‑L1 protein levels. 査読 国際誌

    Eri Tanaka, Yu Miyakawa, Takahiro Kishikawa, Takahiro Seimiya, Takuma Iwata, Kazuyoshi Funato, Nariaki Odawara, Kazuma Sekiba, Mari Yamagami, Tatsunori Suzuki, Rei Ishibashi, Motoyuki Otsuka, Kazuhiko Koike

    Oncology reports   42 ( 4 )   1459 - 1466   2019年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The expression of CDR1‑AS, a representative circular RNA, is closely linked with poor prognosis in gastrointestinal cancers, such as colon, liver, and pancreatic cancers. Although it is well known that CDR1‑AS antagonizes microRNA‑7 function through its sequence similarities in the brain, its biological function and link with the malignant potential of cancer cells remain unclear, partly due to the difficulties of ectopic expression of circular RNAs. In the present study, SW620, a colon cancer cell line that stably expresses CDR1‑AS RNA circularized, was established using the laccase 2 gene cassette, and its biological function associated with malignant behavior was determined. In contrast to previous studies, cell growth or invasion ability was not altered by CDR1‑AS expression. However, the expression levels of CMTM4 and CMTM6, which were recently recognized as critical regulators of PD‑L1 protein expression at the cell surface, were significantly increased. Accordingly, the cell surface PD‑L1 protein levels were increased in CDR1‑AS‑expressing cells. Notably, the effects were not canceled out by overexpressing microRNA‑7, indicating that the increase in cell surface PD‑L1 in CDR1‑AS‑expressing cells was not dependent on microRNA‑7 function. These results indicated that expression of this circular RNA in cancer cells may lead to poor prognosis by increasing cell surface PD‑L1 levels through microRNA‑7‑independent mechanisms.

    DOI: 10.3892/or.2019.7244

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  • Inflammation and de-differentiation in pancreatic carcinogenesis. 査読 国際誌

    Takahiro Seimiya, Motoyuki Otsuka, Takuma Iwata, Eri Tanaka, Tatsunori Suzuki, Kazuma Sekiba, Mari Yamagami, Rei Ishibashi, Kazuhiko Koike

    World journal of clinical cases   6 ( 15 )   882 - 891   2018年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Pancreatic cancer is a malignancy with an extremely poor prognosis. Chronic pancreatitis is a well-known risk factor for pancreatic cancer. Inflammation is thought to influence carcinogenesis through DNA damage and activation of intracellular signaling pathways. Many transcription factors and signaling pathways co-operate to determine and maintain cell identity at each phase of pancreatic organogenesis and cell differentiation. Recent studies have shown that carcinogenesis is promoted through the suppression of transcription factors related to differentiation. Pancreatitis also demonstrates transcriptional changes, suggesting that multifactorial epigenetic changes lead to impaired differentiation. Taken together, these factors may constitute an important framework for pancreatic carcinogenesis. In this review, we discuss the role of inflammation and de-differentiation in the development of pancreatic cancer, as well as the future of novel therapeutic applications.

    DOI: 10.12998/wjcc.v6.i15.882

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  • Liver stiffness measurements in chronic hepatitis C: treatment evaluation and risk assessment. 査読

    Nakagomi R, Tateishi R, Masuzaki R, Soroida Y, Iwai T, Kondo M, Fujiwara N, Sato M, Minami T, Uchino K, Enooku K, Nakagawa H, Asaoka Y, Kondo Y, Tanaka Y, Otsuka M, Kato N, Moriya K, Ikeda H, Koike K

    Journal of gastroenterology and hepatology   2018年11月

  • CPT2 downregulation adapts HCC to lipid-rich environment and promotes carcinogenesis via acylcarnitine accumulation in obesity. 査読 国際誌

    Naoto Fujiwara, Hayato Nakagawa, Kenichiro Enooku, Yotaro Kudo, Yuki Hayata, Takuma Nakatsuka, Yasuo Tanaka, Ryosuke Tateishi, Yohko Hikiba, Kento Misumi, Mariko Tanaka, Akimasa Hayashi, Junji Shibahara, Masashi Fukayama, Junichi Arita, Kiyoshi Hasegawa, Hadassa Hirschfield, Yujin Hoshida, Yoshihiro Hirata, Motoyuki Otsuka, Keisuke Tateishi, Kazuhiko Koike

    Gut   67 ( 8 )   1493 - 1504   2018年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    OBJECTIVE: Metabolic reprogramming of tumour cells that allows for adaptation to their local environment is a hallmark of cancer. Interestingly, obesity-driven and non-alcoholic steatohepatitis (NASH)-driven hepatocellular carcinoma (HCC) mouse models commonly exhibit strong steatosis in tumour cells as seen in human steatohepatitic HCC (SH-HCC), which may reflect a characteristic metabolic alteration. DESIGN: Non-tumour and HCC tissues obtained from diethylnitrosamine-injected mice fed either a normal or a high-fat diet (HFD) were subjected to comprehensive metabolome analysis, and the significance of obesity-mediated metabolic alteration in hepatocarcinogenesis was evaluated. RESULTS: The extensive accumulation of acylcarnitine species was seen in HCC tissues and in the serum of HFD-fed mice. A similar increase was found in the serum of patients with NASH-HCC. The accumulation of acylcarnitine could be attributed to the downregulation of carnitine palmitoyltransferase 2 (CPT2), which was also seen in human SH-HCC. CPT2 downregulation induced the suppression of fatty acid β-oxidation, which would account for the steatotic changes in HCC. CPT2 knockdown in HCC cells resulted in their resistance to lipotoxicity by inhibiting the Src-mediated JNK activation. Additionally, oleoylcarnitine enhanced sphere formation by HCC cells via STAT3 activation, suggesting that acylcarnitine accumulation was a surrogate marker of CPT2 downregulation and directly contributed to hepatocarcinogenesis. HFD feeding and carnitine supplementation synergistically enhanced HCC development accompanied by acylcarnitine accumulation in vivo. CONCLUSION: In obesity-driven and NASH-driven HCC, metabolic reprogramming mediated by the downregulation of CPT2 enables HCC cells to escape lipotoxicity and promotes hepatocarcinogenesis.

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  • Satellite RNA Increases DNA Damage and Accelerates Tumor Formation in Mouse Models of Pancreatic Cancer. 査読 国際誌

    Takahiro Kishikawa, Motoyuki Otsuka, Tatsunori Suzuki, Takahiro Seimiya, Kazuma Sekiba, Rei Ishibashi, Eri Tanaka, Motoko Ohno, Mari Yamagami, Kazuhiko Koike

    Molecular cancer research : MCR   16 ( 8 )   1255 - 1262   2018年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Highly repetitive tandem arrays such as satellite sequences in the centromeric and pericentromeric regions of chromosomes, which were previously considered to be silent, are actively transcribed in various biological processes, including cancers. In the pancreas, this aberrant expression occurs even in Kras-mutated pancreatic intraepithelial neoplasia (PanIN) tissues, which are precancerous lesions. To determine the biological role of satellite RNAs in carcinogenesis in vivo, we constructed mouse major satellite (MajSAT) RNA-expressing transgenic mice. However, these transgenic mice did not show spontaneous malignant tumor formation under normal breeding. Importantly, however, DNA damage was increased in pancreatic tissues induced by caerulein treatment or high-fat diet, which may be due to impaired nuclear localization of Y-Box Binding Protein 1 (YBX1), a component of the DNA damage repair machinery. In addition, when crossed with pancreas-specific Kras-mutant mice, MajSAT RNA expression resulted in an earlier increase in PanIN formation. These results suggest that aberrant MajSAT RNA expression accelerates oncogenesis by increasing the probability of a second driver mutation, thus accelerating cells to exit from the breakthrough phase to the expansion phase.Implications: Aberrant expression of satellite RNAs accelerates oncogenesis through a mechanism involving increased DNA damage. Mol Cancer Res; 16(8); 1255-62. ©2018 AACR.

    DOI: 10.1158/1541-7786.MCR-18-0139

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  • Hepatitis B virus pathogenesis: Fresh insights into hepatitis B virus RNA. 査読 国際誌

    Kazuma Sekiba, Motoyuki Otsuka, Motoko Ohno, Mari Yamagami, Takahiro Kishikawa, Tatsunori Suzuki, Rei Ishibashi, Takahiro Seimiya, Eri Tanaka, Kazuhiko Koike

    World journal of gastroenterology   24 ( 21 )   2261 - 2268   2018年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Hepatitis B virus (HBV) is still a worldwide health concern. While divergent factors are involved in its pathogenesis, it is now clear that HBV RNAs, principally templates for viral proteins and viral DNAs, have diverse biological functions involved in HBV pathogenesis. These functions include viral replication, hepatic fibrosis and hepatocarcinogenesis. Depending on the sequence similarities, HBV RNAs may act as sponges for host miRNAs and may deregulate miRNA functions, possibly leading to pathological consequences. Some parts of the HBV RNA molecule may function as viral-derived miRNA, which regulates viral replication. HBV DNA can integrate into the host genomic DNA and produce novel viral-host fusion RNA, which may have pathological functions. To date, elimination of HBV-derived covalently closed circular DNA has not been achieved. However, RNA transcription silencing may be an alternative practical approach to treat HBV-induced pathogenesis. A full understanding of HBV RNA transcription and the biological functions of HBV RNA may open a new avenue for the development of novel HBV therapeutics.

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  • Identification of PTBP1 responsible for caspase dependent YRNA cleavage 査読

    Jun Ogata, Yuki Sugiura, Akinori Kanai, Masafumi Tanaka, Hirotaka Matsui, Masato Ohtsuka, Toshiya Inaba, Motoyuki Otsuka, Ai Kotani

    BioRxiv doi: https://doi.org/10.1101/298851   2018年5月

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    掲載種別:研究論文(その他学術会議資料等)  

    DOI: 10.1101/298851

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  • DHX9 regulates production of hepatitis B virus-derived circular RNA and viral protein levels. 査読 国際誌

    Kazuma Sekiba, Motoyuki Otsuka, Motoko Ohno, Takahiro Kishikawa, Mari Yamagami, Tatsunori Suzuki, Rei Ishibashi, Takahiro Seimiya, Eri Tanaka, Kazuhiko Koike

    Oncotarget   9 ( 30 )   20953 - 20964   2018年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Hepatitis B virus (HBV) infection, which is a major health concern worldwide, can lead to liver cirrhosis and hepatocellular carcinoma. Although current nucleos(t)ide analogs efficiently inhibit viral reverse transcription and viral DNA load clinically, episomal viral covalently closed circular DNA (cccDNA) minichromosomes and transcripts from cccDNA continue to be expressed over the long term. We hypothesized that, under these conditions, viral transcripts may have biological functions involved in pathogenesis. Here, we show that the host protein DExH-box helicase 9 (DXH9) is associated with viral RNAs. We also show that viral-derived circular RNA is produced during HBV replication, and the amount is increased by knockdown of the DHX9 protein, which, in turn, results in decreased viral protein levels but does not affect the levels of HBV DNA. These phenomena were observed in the HBV-producing cell culture model and HBV mini-circle model mimicking HBV cccDNA, as well as in human primary hepatocytes infected with HBV. Based on these results, we conclude that, in HBV infection, the RNA binding factor DHX9 is a novel regulator of viral circular RNA and viral protein levels.

    DOI: 10.18632/oncotarget.25104

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  • ISGF3 with reduced phosphorylation is associated with constitutive expression of interferon-induced genes in aging cells. 査読 国際誌

    Mari Yamagami, Motoyuki Otsuka, Takahiro Kishikawa, Kazuma Sekiba, Takahiro Seimiya, Eri Tanaka, Tatsunori Suzuki, Rei Ishibashi, Motoko Ohno, Kazuhiko Koike

    NPJ aging and mechanisms of disease   4   11 - 11   2018年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    During cellular aging, many changes in cellular functions occur. A hallmark of aged cells is secretion of inflammatory mediators, which collectively is referred to as the senescence-associated secretory phenotype (SASP). However, the mechanisms underlying such changes are unclear. Canonically, the expression of interferon (IFN)-stimulated genes (ISGs) is induced by IFNs through the formation of the tripartite transcriptional factor ISGF3, which is composed of IRF9 and the phosphorylated forms of STAT1 and STAT2. However, in this study, the constitutive expression of ISGs in human-derived senescent fibroblasts and in fibroblasts from a patient with Werner syndrome, which leads to premature aging, was mediated mainly by the unphosphorylated forms of STATs in the absence of INF production. Under homeostatic conditions, STAT1, STAT2, and IRF9 were localized to the nucleus of aged cells. Although knockdown of JAK1, a key kinase of STAT1 and STAT2, did not affect ISG expression or IFN-stimulated response element (ISRE)-mediated promoter activities in these senescent cells, knockdown of STAT1 or STAT2 decreased ISG expression and ISRE activities. These results suggest that the ISGF3 complex without clear phosphorylation is required for IFN-independent constitutive ISG transcription in senescent cells.

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  • Impact of histone demethylase KDM3A-dependent AP-1 transactivity on hepatotumorigenesis induced by PI3K activation 査読

    T. Nakatsuka, K. Tateishi, Y. Kudo, K. Yamamoto, H. Nakagawa, H. Fujiwara, R. Takahashi, K. Miyabayashi, Y. Asaoka, Y. Tanaka, H. Ijichi, Y. Hirata, M. Otsuka, M. Kato, J. Sakai, M. Tachibana, H. Aburatani, Y. Shinkai, K. Koike

    ONCOGENE   36 ( 45 )   6262 - 6271   2017年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    Epigenetic gene regulation linked to oncogenic pathways is an important focus of cancer research. KDM3A, a histone H3 lysine 9 (H3K9) demethylase, is known to have a pro-tumorigenic function. Here, we showed that KDM3A contributes to liver tumor formation through the phosphatidylinositol 3-kinase (PI3K) pathway, which is often activated in hepatocellular carcinoma. Loss of Kdm3a attenuated tumor formation in Pik3ca transgenic (Tg) mouse livers. Transcriptome analysis of pre-cancerous liver tissues revealed that the expression of activator protein 1 (AP-1) target genes was induced by PI3K activation, but blunted upon Kdm3a ablation. Particularly, the expression of Cd44, a liver cancer stem marker, was regulated by AP-1 in a Kdm3a-dependent manner. We identified Cd44-positive hepatocytes with epithelial-mesenchymal transition-related expression profiles in the Pik3ca Tg liver and confirmed their in vivo tumorigenic capacity. Notably, the number and tumor-initiating capacity of Cd44-positive hepatocytes were governed by Kdm3a. As a mechanism in Kdm3a-dependent AP-1 transcription, Kdm3a recruited c-Jun to the AP-1 binding sites of Cd44, Mmp7 and Pdgfrb without affecting c-Jun expression. Moreover, Brg1, a component of the SWI/SNF chromatin remodeling complex, interacted with c-Jun in a Kdm3a-dependent manner and was bound to the AP-1 binding site of these genes. Finally, KDM3A and c-JUN were co-expressed in 33% of human premalignant lesions with PI3K activation. Our data suggest a critical role for KDM3A in the PI3K/AP-1 oncogenic axis and propose a novel strategy for inhibition of KDM3A against liver tumor development under PI3K pathway activation.

    DOI: 10.1038/onc.2017.222

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  • RASAL1 is a potent regulator of hepatic stellate cell activity and liver fibrosis 査読

    Akemi Takata, Motoyuki Otsuka, Takahiro Kishikawa, Mari Yamagami, Rei Ishibashi, Kazuma Sekiba, Tatsunori Suzuki, Motoko Ohno, Yui Yamashita, Takaya Abe, Ryota Masuzaki, Tsuneo Ikenoue, Kazuhiko Koike

    ONCOTARGET   8 ( 39 )   64840 - 64852   2017年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IMPACT JOURNALS LLC  

    Liver fibrosis, leading to cirrhosis and liver failure, can occur after chronic liver injury. The transition of hepatic stellate cells (HSCs) from quiescent cells into proliferative and fibrogenic cells is a central event in liver fibrosis. Here, we show that RAS protein activator like-1 (RASAL1), a RAS-GTPase-activating protein, which switches off RAS activity, is significantly decreased during HSC activation, and that HSC activation can be antagonized by forced expression of the RASAL1 protein. We demonstrate that RASAL1 suppresses HSC proliferation by regulating the Ras-MAPK pathway, and that RASAL1 suppresses HSC fibrogenic activity by regulating the PKA-LKB1-AMPK-SRF pathway by interacting with angiotensin II receptor, type 1. We also show that RASAL1-deficient mice are more susceptible to liver fibrosis. These data demonstrate that deregulated RASAL1 expression levels and the affected downstream intracellular signaling are central mediators of perpetuated HSC activation and fibrogenesis in the liver.

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  • 膵発癌過程における反復配列RNA異常発現の生物学的意義の検討 査読

    岸川 孝弘, 大塚 基之, 大野 元子, 山上 まり, 石橋 嶺, 關場 一磨, 鈴木 辰典, 小池 和彦

    日本消化器病学会雑誌   114 ( 臨増大会 )   A743 - A743   2017年9月

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    記述言語:日本語   出版者・発行元:(一財)日本消化器病学会  

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  • Biliary epithelial injury-induced regenerative response by IL-33 promotes cholangiocarcinogenesis from peribiliary glands 査読

    Hayato Nakagawa, Nobumi Suzuki, Yoshihiro Hirata, Yohko Hikiba, Yoku Hayakawa, Hiroto Kinoshita, Sozaburo Ihara, Koji Uchino, Yuji Nishikawa, Hideaki Ijichi, Motoyuki Otsuka, Junichi Arita, Yoshihiro Sakamoto, Kiyoshi Hasegawa, Norihiro Kokudo, Keisuke Tateishi, Kazuhiko Koike

    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   114 ( 19 )   E3806 - E3815   2017年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATL ACAD SCIENCES  

    The carcinogenic mechanism of extrahepatic cholangiocarcinoma (ECC) is unclear, due at least in part to the lack of an appropriate mouse model. Because human studies have reported frequent genetic alterations in the Ras-and TGF beta/SMAD-signaling pathways in ECC, mice with tamoxifen-inducible, duct-cell-specific Kras activation and a TGF beta receptor type 2 (TGF beta R2) deletion were first generated by crossing LSL-Kras(G12D), Tgfbr2(flox/flox), and K19(CreERT) mice (KT-K19(CreERT)). However, KT-K19CreERT mice showed only mild hyperplasia of biliary epithelial cells (BECs) in the extrahepatic bile duct (EHBD) and died within 7 wk, probably a result of lung adenocarcinomas. Next, to analyze the additional effect of E-cadherin loss, KT-K19CreERT mice were crossed with CDH1flox/flox mice (KTCK19CreERT). Surprisingly, KTC-K19CreERT mice exhibited a markedly thickened EHBD wall accompanied by a swollen gallbladder within 4 wk after tamoxifen administration. Histologically, invasive periductal infiltrating-type ECC with lymphatic metastasis was observed. Time-course analysis of EHBD revealed that recombined BECs lining the bile duct lumen detached due to E-cadherin loss, whereas recombined cells could survive in the peribiliary glands (PBGs), which are considered a BEC stem-cell niche. Detached dying BECs released high (l)evels of IL-33, as determined by microarray analysis using biliary organoids, and stimulated inflammation and a regenerative response by PBGs, leading eventually to ECC development. Cell lineage tracing suggested PBGs as the cellular origin of ECC. IL-33 cooperated with Kras and TGF beta R2 mutations in the development of ECC, and anti-IL-33 treatment suppressed ECC development significantly. Thus, this mouse model provided insight into the carcinogenic mechanisms, cellular origin, and potential therapeutic targets of ECC.

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  • Transcriptional activation of the MICA gene with an engineered CRISPR-Cas9 system 査読

    Kazuma Sekiba, Mari Yamagami, Motoyuki Otsuka, Tatsunori Suzuki, Takahiro Kishikawa, Rei Ishibashi, Motoko Ohno, Masaya Sato, Kazuhiko Koike

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   486 ( 2 )   521 - 525   2017年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Major histocompatibility complex class I polypeptide-related sequence A (MICA) is a prototypical NKG2D ligand. Because immune cells, such as natural killer (NK) cells, recognize virally infected or transformed cells and eliminate them through the interaction between NKG2D receptors on NK cells and NKG2D ligands on pathogenic cells, MICA expression levels are associated with NK cell-mediated immunity. Here, we report that an engineered clustered regularly interspaced short palindromic repeats-Cas9-related complex targeting MICA gene promoter sequences activates transcription of the MICA gene from its endogenous locus. Inhibiting microRNA function, which targets the 3' untranslated region of the MICA gene, enhances this activation. These results demonstrate that the combination of Cas9-based transcriptional activators and simultaneous modulation of microRNA function may be a powerful tool for enhancing MICA protein expression and efficient anti-pathogenic cell immunity. (C) 2017 Elsevier Inc. All rights reserved.

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  • MicroRNAs and liver disease 査読

    Motoyuki Otsuka, Takahiro Kishikawa, Takeshi Yoshikawa, Mari Yamagami, Motoko Ohno, Akemi Takata, Chikako Shibata, Rei Ishibashi, Kazuhiko Koike

    JOURNAL OF HUMAN GENETICS   62 ( 1 )   75 - 80   2017年1月

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    記述言語:英語   出版者・発行元:NATURE PUBLISHING GROUP  

    The biological roles of microRNAs (miRNAs) have been extensively studied. miRNA122 represents more than half of the miRNAs expressed in the liver and has various physiological and pathological functions, which include enhancing hepatitis virus replication, regulating lipid metabolism and suppressing hepatocellular carcinoma. miRNAs, whether globally or individually, have been linked with hepatocarcinogenesis. Furthermore, some miRNAs have been shown to be involved in the pathogenesis of nonalcoholic steatohepatitis. Using nucleotide-based strategies, these miRNAs may be developed as potential therapeutic targets. Because changes in miRNA expression can be measured in sera, they may be used as non-invasive biomarkers if they correctly reflect the pathological state of the liver. In this review, we show the biological roles of representative miRNAs in liver disease and discuss the current issues that remain to be clarified for future clinical applications.

    DOI: 10.1038/jhg.2016.53

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  • Mutual antagonism between hepatitis B viral mRNA and host microRNA let-7 査読

    Akemi Takata, Motoyuki Otsuka, Motoko Ohno, Takahiro Kishikawa, Takeshi Yoshikawa, Kazuhiko Koike

    SCIENTIFIC REPORTS   6   23237   2016年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    The interplay between viral and host factors plays a major role in viral pathogenesis. Hepatitis B virus (HBV) infection is a global health problem that leads to liver cirrhosis and hepatocellular carcinoma (HCC). Although HBV proteins have been studied extensively about their implication in hepatocarcinogenesis, the molecular mechanisms of oncogenesis are still largely unknown. A recent concept in gene regulation, in which competitive endogenous RNAs compete for common microRNAs (miRNAs), suggests that mRNA targets are key elements in the regulation of miRNA availability. Here, we show that HBV mRNA in the preS2 region can be targeted by host miRNA let-7 g. This leads to the sequestration of let-7 g and inhibition of let-7 g function. The expression of HBV transcripts, including the preS2 region, de-repressed let-7 g targets, which may contribute to long-term oncogenesis. HBV transcript-expressing transgenic mice, but not non-targeted transcript-expressing mice, were more prone to chemically induced hepatoocarcinogenesis. Let-7 target protein expression was upregulated in human HCC tissues derived from HBV-infected patients. On the other hand, let-7 g inhibited HBV preS2 protein expression and viral products. These results suggest that the interplay between viral intermediate transcripts during HBV replication and host miRNAs is crucial to the pathogenesis of chronic viral infection.

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  • Development of a screening method to identify regulators of MICA shedding 査読

    Takahiro Kishikawa, Motoyuki Otsuka, Motoko Ohno, Takeshi Yoshikawa, Masaya Sato, Kazuhiko Koike

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   465 ( 4 )   764 - 768   2015年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Immune cells, such as natural killer (NK) cells, recognize virally infected and transformed cells, and eliminate them through the interaction between NKG2D receptors on NK cells and NKG2D ligands on pathogenic cells. Shedding of NKG2D ligands is thought to be a type of counter-mechanism employed by pathogenic cells to evade from NKG2D-mediated immune surveillance. MHC class I polypeptide-related sequence A (MICA) is a prototypical NKG2D ligand. We previously reported that, in soluble form, MICA expression levels are significantly associated with hepatitis virus-induced hepatocellular carcinoma. Here, we report a MICA shedding assay that utilizes membrane-bound MICA tagged at its N-terminus with a nano-luciferase reporter to quantify MICA shedding into culture media. Using this method, we screened a compound library and identified putative regulators of MICA shedding that have the potential to enhance the immune reaction by simultaneously increasing cell surface MICA levels and decreasing soluble MICA levels. This shedding assay may be useful for screening regulators of cell surface molecule shedding. (C) 2015 Elsevier Inc. All rights reserved.

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  • ROCK inhibition enhances microRNA function by promoting deadenylation of targeted mRNAs via increasing PAIP2 expression 査読

    Takeshi Yoshikawa, Jianfeng Wu, Motoyuki Otsuka, Takahiro Kishikawa, Motoko Ohno, Chikako Shibata, Akemi Takata, Felicia Han, Young Jun Kang, Chyi-Ying A. Chen, Ann-Bin Shyu, Jiahuai Han, Kazuhiko Koike

    NUCLEIC ACIDS RESEARCH   43 ( 15 )   7577 - 7589   2015年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

    The reduced expression levels and functional impairment of global miRNAs are related to various human diseases, including cancers. However, relatively little is known about how global miRNA function may be upregulated. Here, we report that global miRNA function can be enhanced by Rho-associated, coiled-coil-containing protein kinase (ROCK) inhibitors. The regulation of miRNA function by ROCK inhibitors is mediated, at least in part, by poly(A)-binding protein-interacting protein 2 (PAIP2), which enhances poly(A)-shortening of miRNA-targeted mRNAs and leads to global upregulation of miRNA function. In the presence of a ROCK inhibitor, PAIP2 expression is enhanced by the transcription factor hepatocyte nuclear factor 4 alpha (HNF4A) through increased ROCK1 nuclear localization and enhanced ROCK1 association with HNF4A. Our data reveal an unexpected role of ROCK1 as a cofactor of HNF4A in enhancing PAIP2 transcription. ROCK inhibitors may be useful for the various pathologies associated with the impairment of global miRNA function.

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  • Circulating RNAs as new biomarkers for detecting pancreatic cancer 査読

    Takahiro Kishikawa, Motoyuki Otsuka, Motoko Ohno, Takeshi Yoshikawa, Akemi Takata, Kazuhiko Koike

    WORLD JOURNAL OF GASTROENTEROLOGY   21 ( 28 )   8527 - 8540   2015年7月

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    記述言語:英語   出版者・発行元:BAISHIDENG PUBLISHING GROUP INC  

    Pancreatic cancer remains difficult to treat and has a high mortality rate. It is difficult to diagnose early, mainly due to the lack of screening imaging modalities and specific biomarkers. Consequently, it is important to develop biomarkers that enable the detection of early stage tumors. Emerging evidence is accumulating that tumor cells release substantial amounts of RNA into the bloodstream that strongly resist RNases in the blood and are present at sufficient levels for quantitative analyses. These circulating RNAs are upregulated in the serum and plasma of cancer patients, including those with pancreatic cancer, compared with healthy controls. The majority of RNA biomarker studies have assessed circulating microRNAs (miRs), which are often tissue-specific. There are few reports of the tumor-specific upregulation of other types of small non-coding RNAs (ncRNAs), such as small nucleolar RNAs and Piwi-interacting RNAs. Long ncRNAs (lncRNAs), such as HOTAIR and MALAT1, in the serum/plasma of pancreatic cancer patients have also been reported as diagnostic and prognostic markers. Among tissue-derived RNAs, some miRs show increased expression even in pre-cancerous tissues, and their expression profiles may allow for the discrimination between a chronic inflammatory state and carcinoma. Additionally, some miRs and lncRNAs have been reported with significant alterations in expression according to disease progression, and they may thus represent potential candidate diagnostic or prognostic biomarkers that may be used to evaluate patients once detection methods in peripheral blood are well established. Furthermore, recent innovations in high-throughput sequencing techniques have enabled the discovery of unannotated tumor-associated ncRNAs and tumor-specific alternative splicing as novel and specific biomarkers of cancers. Although much work is required to clarify the release mechanism, origin of tumor-specific circulating RNAs, and selectivity of carrier complexes, and technical advances must also be achieved, such as creating a consensus normalization protocol for quantitative data analysis, circulating RNAs are largely unexplored and might represent novel clinical biomarkers.

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  • Novel therapeutic approaches for hepatitis B virus covalently closed circular DNA 査読

    Motoko Ohno, Motoyuki Otsuka, Takahiro Kishikawa, Takeshi Yoshikawa, Akemi Takata, Kazuhiko Koike

    WORLD JOURNAL OF GASTROENTEROLOGY   21 ( 23 )   7084 - 7088   2015年6月

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    記述言語:英語   出版者・発行元:BAISHIDENG PUBLISHING GROUP INC  

    Hepatitis B virus (HBV) infection is a major global health problem. Although current therapies, such as the use of nucleos(t) ide analogs, inhibit HBV replication efficiently, they do not eliminate covalently closed circular DNA (cccDNA), which persists in hepatocyte nuclei. As HBV cccDNA is a viral transcription template, novel therapeutic approaches to directly target HBV cccDNA are necessary to completely eradicate persistent HBV infections. HBV cccDNA levels in HBV-infected human liver cells are extremely low; thus, more reliable and simple measurement methods are needed to correctly monitor their levels during therapeutic treatment. Although reverse transcription-polymerase chain reaction or Southern blot procedures are currently used in research studies, these methods are not completely reliable and are also time-consuming and labor-intensive. Genome editing technologies, such as zinc finger nucleases, transcription activator-like effector nucleases, and the clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) system, which are designed to target specific DNA sequences, represent highly promising potential therapeutic tools. In particular, the CRISPR/Cas9 system is an easily customizable sequences-pecific nuclease with high flexibility and may be the most feasible approach to target HBV cccDNA. Further research to develop easier, safer, and more effective protocols should be pursued.

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  • Tissue-Specific Regulation of p38α-Mediated Inflammation in Con A-Induced Acute Liver Damage. 査読

    Kang YJ, Bang BR, Otsuka M, Otsu K

    Journal of immunology (Baltimore, Md. : 1950)   194 ( 10 )   4759 - 4766   2015年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Decreased miR122 in hepatocellular carcinoma leads to chemoresistance with increased arginine 査読

    Takahiro Kishikawa, Motoyuki Otsuka, Poh Seng Tan, Motoko Ohno, Xiaochen Sun, Takeshi Yoshikawa, Chikako Shibata, Akemi Takata, Kentaro Kojima, Kenji Takehana, Maki Ohishi, Sana Ota, Tomoyuki Noyama, Yuji Kondo, Masaya Sato, Tomoyoshi Soga, Yujin Hoshida, Kazuhiko Koike

    Oncotarget   6 ( 10 )   8339 - 8352   2015年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Impact Journals LLC  

    Reduced expression of microRNA122 (miR122), a liver-specific microRNA, is frequent in hepatocellular carcinoma (HCC). However, its biological significances remain poorly understood. Because deregulated amino acid levels in cancers can affect their biological behavior, we determined the amino acid levels in miR122- silenced mouse liver tissues, in which intracellular arginine levels were significantly increased. The increased intracellular arginine levels were through upregulation of the solute carrier family 7 (SLC7A1), a transporter of arginine and a direct target of miR122. Arginine is the substrate for nitric oxide (NO) synthetase, and intracellular NO levels were increased in miR122-silenced HCC cells, with increased resistance to sorafenib, a multikinase inhibitor. Conversely, maintenance of the miR122-silenced HCC cells in arginine-depleted culture media, as well as overexpression of miR122 in miR122-low-expressing HCC cells, reversed these effects and rendered the cells more sensitive to sorafenib. Using a reporter knock-in construct, chemical compounds were screened, and Wee1 kinase inhibitor was identified as upregulators of miR122 transcription, which increased the sensitivity of the cells to sorafenib. These results provide an insight into sorafenib resistance in miR122-low HCC, and suggest that arginine depletion or a combination of sorafenib with the identified compound may provide promising approaches to managing this HCC subset.

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  • Diagnostic and therapeutic application of noncoding RNAs for hepatocellular carcinoma 査読

    Chikako Shibata, Motoyuki Otsuka, Takahiro Kishikawa, Motoko Ohno, Takeshi Yoshikawa, Akemi Takata, Kazuhiko Koike

    World Journal of Hepatology   7 ( 1 )   1 - 6   2015年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Baishideng Publishing Group Co  

    MicroRNAs (miRNAs) are small, noncoding RNA molecules that regulate gene expression posttranscriptionally, targeting thousands of messenger RNAs. Long noncoding RNAs (lncRNAs), another class of noncoding RNAs, have been determined to be also involved in transcription regulation and translation of target genes. Since deregulated expression levels or functions of miRNAs and lncRNAs in hepatocellular carcinoma (HCC) are frequently observed, clinical use of noncoding RNAs for novel diagnostic and therapeutic applications in the management of HCCs is highly and emergently expected. Here, we summarize recent findings regarding deregulated miRNAs and lncRNAs for their potential clinical use as diagnostic and prognostic biomarkers of HCC. Specifically, we emphasize the deregulated expression levels of such noncoding RNAs in patients' sera as noninvasive biomarkers, a field that requires urgent improvement in the clinical surveillance of HCC. Since nucleotide-based strategies are being applied to clinical therapeutics, we further summarize clinical and preclinical trials using oligonucleotides involving the use of miRNAs and small interfering RNAs against HCC as novel therapeutics. Finally, we discuss current open questions, which must be clarified in the near future for realistic clinical applications of these new strategies.

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  • Loss of histone demethylase KDM6B enhances aggressiveness of pancreatic cancer through downregulation of C/EBPα 査読

    Yamamoto K, Tateishi K, Kudo Y, Sato T, Yamamoto S, Miyabayashi K, Matsusaka K, Asaoka Y, Ijichi H, Hirata Y, Otsuka M, Nakai Y, Isayama H, Ikenoue T, Kurokawa M, Fukayama M, Kokudo N, Omata M, Koike K

    Carcinogenesis   35 ( 11 )   2404 - 2414   2014年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Impact of PNPLA3 polymorphisms on the development of hepatocellular carcinoma in patients with chronic hepatitis C virus infection 査読

    Masaya Sato, Naoya Kato, Ryosuke Tateishi, Ryosuke Muroyama, Norie Kowatari, Wenwen Li, Kaku Goto, Motoyuki Otsuka, Shuichiro Shiina, Haruhiko Yoshida, Masao Omata, Kazuhiko Koike

    HEPATOLOGY RESEARCH   44 ( 10 )   E137 - E144   2014年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-BLACKWELL  

    Aim: The PNPLA3 rs738409 C&gt;G polymorphism (encoding for I148M) has recently been identified as a susceptibility factor for steatosis-mediated liver damage. We evaluated the influence of this polymorphism on hepatocarcinogenesis in patients with chronic hepatitis C (CHC) virus infection.
    Methods: We genotyped the rs738409 single nucleotide polymorphism in 358 hepatitis C-associated hepatocellular carcinoma (HCC) patients and correlated the age at onset of HCC and the interval between hepatitis C virus (HCV) infection and the development of HCC in patients with each genotype.
    Results: The frequencies of CC, CG and GG genotypes were 27.9% (100/358), 49.2% (176/358) and 22.9% (82/358), respectively, and were in Hardy-Weinberg equilibrium. The median age at onset of HCC for the GG genotype was significantly younger compared to for non-GG genotypes (67.81 vs 69.87 years, P &lt; 0.001), and the median interval between HCV infection and the development of HCC was significantly shorter in patients with the GG genotype (39.96 vs 40.85 years, P = 0.008). PNPLA3 GG genotype was also associated with a higher aspartate aminotransferase level (69.5 vs 59.0 IU/L, P = 0.02), lower prothrombin time (73.0% vs 78.0%, P = 0.008) and a higher prevalence of histological steatosis (40.0% vs. 22.2%, P = 0.01) at the time of HCC onset.
    Conclusion: The PNPLA3 genotype GG may be associated with accelerated hepatocarcinogenesis in CHC patients through increased steatosis in the liver.

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  • The flavonoid apigenin inhibits hepatitis C virus replication by decreasing mature microRNA122 levels 査読

    Chikako Shibata, Motoko Ohno, Motoyuki Otsuka, Takahiro Kishikawa, Kaku Goto, Ryosuke Muroyama, Naoya Kato, Takeshi Yoshikawa, Akemi Takata, Kazuhiko Koike

    VIROLOGY   462   42 - 48   2014年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Despite recent progress in the development of direct-acting antivirals against hepatitis C virus (HCV), chronic HCV infection remains an important health burden worldwide. MicroRNA122 (miR122), a liver-specific microRNA (miRNA), positively regulates HCV replication, and systemic application of antisense oligonucleotides against miR122 led to the long-lasting suppression of HCV viremia in human clinical trials. Here, we report that apigenin, a flavonoid and an inhibitor of maturation of a subset of miRNAs, inhibits HCV replication in vitro. Apigenin decreased the expression levels of mature miR122 without significantly affecting cell growth. Because supplementation of synthesized miR122 oligonucleotides or overexpression of constitutively active TRBP blocked these effects, the inhibitory effects of apigenin on HCV replication seemed to be dependent on the reduction of mature miR122 expression levels through inhibition of TRBP phosphorylation. Thus, apigenin intake, either through regular diet or supplements, may decrease HCV replication in chronically infected patients. (C) 2014 The Authors. Published by Elsevier Inc.

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  • Specific delivery of microRNA93 into HBV-replicating hepatocytes downregulates protein expression of liver cancer susceptible gene MICA 査読

    Motoko Ohno, Motoyuki Otsuka, Takahiro Kishikawa, Chikako Shibata, Takeshi Yoshikawa, Akemi Takata, Ryosuke Muroyama, Norie Kowatari, Masaya Sato, Naoya Kato, Shun'ichi Kuroda, Kazuhiko Koike

    ONCOTARGET   5 ( 14 )   5581 - 5590   2014年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IMPACT JOURNALS LLC  

    Chronic hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC). To date, the lack of efficient in vitro systems supporting HBV infection and replication has been a major limitation of HBV research. Although primary human hepatocytes support the complete HBV life cycle, their limited availability and difficulties with gene transduction remain problematic. Here, we used human primary hepatocytes isolated from humanized chimeric uPA/SCID mice as efficient sources. These hepatocytes supported HBV replication in vitro. Based on analyses of mRNA and microRNA (miRNA) expression levels in HBV-infected hepatocytes, miRNA93 was significantly downregulated during HBV infection. MiRNA93 is critical for regulating the expression levels of MICA protein, which is a determinant for HBV-induced HCC susceptibility. Exogenous addition of miRNA93 in HBV-infected hepatocytes using bionanocapsules consisted of HBV envelope L proteins restored MICA protein expression levels in the supernatant. These results suggest that the rescued suppression of soluble MICA protein levels by miRNA93 targeted to HBV-infected hepatocytes using bionanocapsules may be useful for the prevention of HBV-induced HCC by altering deregulated miRNA93 expression.

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  • IL28B minor allele is associated with a younger age of onset of hepatocellular carcinoma in patients with chronic hepatitis C virus infection 査読

    Masaya Sato, Naoya Kato, Ryosuke Tateishi, Ryosuke Muroyama, Norie Kowatari, Wenwen Li, Kaku Goto, Motoyuki Otsuka, Shuichiro Shiina, Haruhiko Yoshida, Masao Omata, Kazuhiko Koike

    JOURNAL OF GASTROENTEROLOGY   49 ( 4 )   748 - 754   2014年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER JAPAN KK  

    IL28B polymorphisms were shown to be associated with a response to peg-interferon-based treatment in chronic hepatitis C (CHC) and spontaneous clearance. However, little is known about how this polymorphism affects the course of CHC, including the development of hepatocellular carcinoma (HCC). We evaluated the influence of IL28B polymorphisms on hepatocarcinogenesis in CHC patients.
    We genotyped the rs8099917 single-nucleotide polymorphism in 351 hepatitis C-associated HCC patients without history of IFN-based treatment, and correlated the age at onset of HCC in patients with each genotype.
    Frequencies of TT, TG, and GG genotypes were 74.3 % (261/351), 24.8 % (87/351), and 0.9 % (3/351), respectively. The mean ages at onset of HCC for TT, TG, and GG genotypes were 69.9, 67.5 and 66.8, respectively. In multivariate analysis, IL28B minor allele (TG and GG genotypes) was an independent risk factor for younger age at onset of HCC (P = 0.02) in males (P &lt; 0.001) with higher body mass index (BMI; P = 0.009). The IL28B minor allele was also associated with a lower probability of having aspartate aminotransferase-to-platelet ratio index (APRI) &gt; 1.5 (minor vs. major, 46.7 vs. 58.6 %; P = 0.01), lower AST (69.1 vs. 77.7 IU/L, P = 0.02), lower ALT (67.8 vs. 80.9 IU/L, P = 0.002), higher platelet count (12.8 vs. 11.2 x 10(4)/mu L, P = 0.002), and higher prothrombin time (79.3 vs. 75.4 %, P = 0.002).
    The IL28B minor allele was associated with lower inflammatory activity and less progressed fibrosis of the liver; however, it constituted a risk factor for younger-age onset of HCC in CHC patients.

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  • The role of microRNAs in hepatocarcinogenesis: current knowledge and future prospects 査読

    Motoyuki Otsuka, Takahiro Kishikawa, Takeshi Yoshikawa, Motoko Ohno, Akemi Takata, Chikako Shibata, Kazuhiko Koike

    JOURNAL OF GASTROENTEROLOGY   49 ( 2 )   173 - 184   2014年2月

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    記述言語:英語   出版者・発行元:SPRINGER JAPAN KK  

    MicroRNAs (miRNAs) are small, noncoding RNA molecules that regulate gene expression post-transcriptionally through complementary base pairing with thousands of messenger RNAs. Although the precise biological functions of individual miRNAs are still unknown, miRNAs are speculated to play important roles in diverse biological processes through fine regulation of their target gene expression. A growing body of data indicates the deregulation of miRNAs during hepatocarcinogenesis. In this review, we summarize recent findings regarding deregulated miRNA expression and their possible target genes in hepatocarcinogenesis, with emphasis on inflammation-related hepatocarcinogenesis. Because miRNA-based strategies are being applied to clinical therapeutics, precise knowledge of miRNA functions is crucial both scientifically and clinically. We discuss the current open questions from these points of view, which must be clarified in the near future.

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  • Histone demethylase KDM4C regulates sphere formation by mediating the cross talk between Wnt and Notch pathways in colonic cancer cells 査読

    Shinzo Yamamoto, Keisuke Tateishi, Yotaro Kudo, Keisuke Yamamoto, Takayuki Isagawa, Genta Nagae, Takuma Nakatsuka, Yoshinari Asaoka, Hideaki Ijichi, Yoshihiro Hirata, Motoyuki Otsuka, Tsuneo Ikenoue, Hiroyuki Aburatani, Masao Omata, Kazuhiko Koike

    CARCINOGENESIS   34 ( 10 )   2380 - 2388   2013年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

    Alterations in genes coding for histone modifiers are found in human cancers, suggesting that histone modification is involved in malignant features of neoplastic cells. This study showed that a histone demethylase KDM4C is significant for colonosphere formation by mediating the cross talk between oncogenic pathways through a feed-forward mechanism. The expression of KDM4C gene was increased in spheres from colorectal cancer (CRC) cells and the knockdown (KD) of KDM4C eliminated colonosphere formation. We found that the KD of -catenin, an important oncogenic factor in CRC, resulted in not only decreased sphere formation but also impaired upregulation of KDM4C gene in spheres. -Catenin bound to the KDM4C promoter, suggesting that KDM4C is involved in the sphere-forming ability downstream of -catenin in CRC cells. Microarray analysis identified the JAG1 gene that codes for a notch ligand Jagged1 responsible for sphere formation as a target of KDM4C. KDM4C KD decreased the expression of JAG1 gene, and the downregulation of JAG1 gene recapitulated the impaired colonosphere formation. JAG1 is also a target of -catenin, and chromatin immunoprecipitation analysis showed the binding of -catenin and KDM4C onto the JAG1 promoter during colonosphere formation. Importantly, KDM4C KD ruined the recruitment of -catenin onto the JAG1 promoter independently of the H3-K9 methylation status and blunted JAG1 expression during sphere formation. These data indicate that KDM4C maintains the sphere-forming capacity in CRCs by mediating the -catenin-dependent transcription of JAG1 in a feed-forward manner.

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  • Activation of p38α in T cells regulates the intestinal host defense against attaching and effacing bacterial infections. 査読

    Shim EJ, Bang BR, Kang SG, Ma J, Otsuka M, Kang J, Stahl M, Han J, Xiao C, Vallance BA, Kang YJ

    Journal of immunology (Baltimore, Md. : 1950)   191 ( 5 )   2764 - 2770   2013年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:5  

    DOI: 10.4049/jimmunol.1300908

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  • Unique Haploinsufficient Role of the MicroRNA-Processing Molecule Dicer1 in a Murine Colitis-Associated Tumorigenesis Model 査読

    Takeshi Yoshikawa, Motoyuki Otsuka, Takahiro Kishikawa, Akemi Takata, Motoko Ohno, Chikako Shibata, Young Jun Kang, Haruhiko Yoshida, Kazuhiko Koike

    PLOS ONE   8 ( 9 )   e71969   2013年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PUBLIC LIBRARY SCIENCE  

    A widespread downregulated expression of microRNAs (miRNAs) is commonly observed in human cancers. Similarly, deregulated expression of miRNA-processing pathway components, which results in the reduction of global miRNA expression, may also be associated with tumorigenesis. Here, we show that specific ablation of Dicer1 in intestinal epithelial cells accelerates intestinal inflammation-associated tumorigenesis. This effect was apparent only when a single copy of Dicer1 was deleted, but not with complete Dicer1 ablation. DICER expression and subsequent mature miRNA levels were inversely correlated with the number of intact Dicer1 alleles. Because the expression levels of DICER were retained in tumors and its surrounding tissues even after induction of colitis-associated tumors, the effects of Dicer1 deletion were cell-autonomous. Although the expression levels of representative oncogenes and tumor suppressor genes were in most cases inversely correlated with the expression levels of DICER, some genes were not affected by Dicer1 deletion. Thus, deregulating the delicate balance between the expression levels of tumor-promoting and - suppressive genes may be crucial for tumorigenesis in this unique haploinsufficient case.

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  • Inhibition of microRNA122 decreases SREBP1 expression by modulating suppressor of cytokine signaling 3 expression 査読

    Chikako Shibata, Takahiro Kishikawa, Motoyuki Otsuka, Motoko Ohno, Takeshi Yoshikawa, Akemi Takata, Haruhiko Yoshida, Kazuhiko Koike

    Biochemical and Biophysical Research Communications   438 ( 1 )   230 - 235   2013年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:1  

    While inhibition of microRNA122 (miR122) function in vivo results in reduced serum cholesterol and fatty acid levels, the molecular mechanisms underlying the link between miR122 function and lipid metabolism remains unclear. Because the expression of SREBP1, a central transcription factor involved in lipid metabolism, is known to be increased by suppressor of cytokine signaling 3 (SOCS3) expression, and because we previously found that SOCS3 expression is regulated by miR122, in this study, we examined the correlation between miR122 status and the expression levels of SOCS3 and SREBP1. SREBP1 expression decreased when SOCS3 expression was reduced by miR122 silencing in vitro. Conversely, SREBP1 expression in miR122-silenced cells was restored by enforced expression of SOCS3. Such correlations were observed in human liver tissues with different miR122 expression levels. These signaling links may explain one of the molecular mechanisms linking inhibition of miR122 function or decreased expression of miR122 to decreased fatty acid and cholesterol levels, in the inhibition of miR122 function, or in pathological status in chronic liver diseases. © 2013 Elsevier Inc.

    DOI: 10.1016/j.bbrc.2013.07.064

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  • The flavonoid apigenin improves glucose tolerance through inhibition of microRNA maturation in miRNA103 transgenic mice 査読

    Motoko Ohno, Chikako Shibata, Takahiro Kishikawa, Takeshi Yoshikawa, Akemi Takata, Kentaro Kojima, Masao Akanuma, Young Jun Kang, Haruhiko Yoshida, Motoyuki Otsuka, Kazuhiko Koike

    SCIENTIFIC REPORTS   3   2553   2013年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    Polyphenols are representative bioactive substances with diverse biological effects. Here, we show that apigenin, a flavonoid, has suppressive effects on microRNA (miRNA) function. The effects were mediated by impaired maturation of a subset of miRNAs, probably through inhibition of the phosphorylation of TRBP, a component of miRNA-generating complexes via impaired mitogen-activated protein kinase (MAPK) Erk activation. While glucose intolerance was observed in miRNA103 (miR103)-overexpressing transgenic mice, administration of apigenin improved this pathogenic status likely through suppression of matured miR103 expression levels. These results suggest that apigenin may have favorable effects on the pathogenic status induced by overexpression of miRNA103, whose maturation is mediated by phosphorylated TRBP.

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  • Transdifferentiation of human fibroblasts into hepatocyte-like cells by defined transcriptional factors 査読

    Tomomi Kogiso, Hikaru Nagahara, Motoyuki Otsuka, Keiko Shiratori, Steven F. Dowdy

    HEPATOLOGY INTERNATIONAL   7 ( 3 )   937 - 944   2013年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Liver transplantation is currently the only curative therapeutic option for end-stage liver cirrhosis. However, due to the limitations of donor liver availability and occasional rejection, it cannot always be successfully applied. In this study, we determined whether fibroblasts can be transdifferentiated into hepatocyte-like cells by transcription factors that initiate and maintain hepatocyte differentiation.
    Fibroblasts were transduced with retrovirus vectors carrying FOXA2, HNF4 alpha, and C/EBP beta. To enhance the efficiency of transdifferentiation, cMyc was also expressed.
    Transdifferentiation was successful using both neonatal fibroblasts and human forehead fibroblasts. The transdifferentiated cells produced hepatocyte-specific proteins such as albumin and cytochrome, and had important hepatocyte-specific functions, such as glycogen storage and indocyanine green uptake, suggesting that the cells function at least as partial hepatocytes.
    These results provide a novel method of generating differentiated hepatocyte-like cells, and may represent an alternative source of cells for future cell-based therapeutics for end-stage liver diseases.

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  • A genome-wide association study of HCV-induced liver cirrhosis in the Japanese population identifies novel susceptibility loci at the MHC region 査読

    Yuji Urabe, Hidenori Ochi, Naoya Kato, Vinod Kumar, Atsushi Takahashi, Ryosuke Muroyama, Naoya Hosono, Motoyuki Otsuka, Ryosuke Tateishi, Paulisally Hau Yi Lo, Chizu Tanikawa, Masao Omata, Kazuhiko Koike, Daiki Miki, Hiromi Abe, Naoyuki Kamatani, Joji Toyota, Hiromitsu Kumada, Michiaki Kubo, Kazuaki Chayama, Yusuke Nakamura, Koichi Matsuda

    Journal of Hepatology   58 ( 5 )   875 - 882   2013年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Background &amp
    Aims: We performed a genome-wide association study (GWAS) of hepatitis C virus (HCV)-induced liver cirrhosis (LC) to identify predictive biomarkers for the risk of LC in patients with chronic hepatitis C (CHC). Methods: A total of 682 HCV-induced LC cases and 1045 CHC patients of Japanese origin were genotyped by Illumina Human Hap 610-Quad bead Chip. Results: Eight SNPs which showed possible associations (p &lt
    1.0 × 10-5) at the GWAS stage were further genotyped using 936 LC cases and 3809 CHC patients. We found that two SNPs within the major histocompatibility complex (MHC) region on chromosome 6p21, rs910049 and rs3135363, were significantly associated with the progression from CHC to LC (pcombined = 9.15 × 10 -11 and 1.45 × 10-10, odds ratio (OR) = 1.46 and 1.37, respectively). We also found that HLA-DQA1*0601 and HLA-DRB1*0405 were associated with the progression from CHC to LC (p = 4.53 × 10-4 and 1.54 × 10-4 with OR = 2.80 and 1.45, respectively). Multiple logistic regression analysis revealed that rs3135363, rs910049, and HLA-DQA1*0601 were independently associated with the risk of HCV-induced LC. In addition, individuals with four or more risk alleles for these three loci have a 2.83-fold higher risk for LC than those with no risk allele, indicating the cumulative effects of these variations. Conclusions: Our findings elucidated the crucial roles of multiple genetic variations within the MHC region as prognostic/predictive biomarkers for CHC patients. © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

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  • MicroRNA-140 acts as a liver tumor suppressor by controlling NF-kappa B activity by directly targeting DNA methyltransferase 1 (Dnmt1) expression 査読

    Akemi Takata, Motoyuki Otsuka, Takeshi Yoshikawa, Takahiro Kishikawa, Yohko Hikiba, Shuntaro Obi, Tadashi Goto, Young Jun Kang, Shin Maeda, Haruhiko Yoshida, Masao Omata, Hiroshi Asahara, Kazuhiko Koike

    HEPATOLOGY   57 ( 1 )   162 - 170   2013年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-BLACKWELL  

    MicroRNAs (miRNAs) are small RNAs that regulate the expression of specific target genes. While deregulated miRNA expression levels have been detected in many tumors, whether miRNA functional impairment is also involved in carcinogenesis remains unknown. We investigated whether deregulation of miRNA machinery components and subsequent functional impairment of miRNAs are involved in hepatocarcinogenesis. Among miRNA-containing ribonucleoprotein complex components, reduced expression of DDX20 was frequently observed in human hepatocellular carcinomas, in which enhanced nuclear factor-?B (NF-?B) activity is believed to be closely linked to carcinogenesis. Because DDX20 normally suppresses NF-?B activity by preferentially regulating the function of the NF-?B-suppressing miRNA-140, we hypothesized that impairment of miRNA-140 function may be involved in hepatocarcinogenesis. DNA methyltransferase 1 (Dnmt1) was identified as a direct target of miRNA-140, and increased Dnmt1 expression in DDX20-deficient cells hypermethylated the promoters of metallothionein genes, resulting in decreased metallothionein expression leading to enhanced NF-?B activity. MiRNA-140-knockout mice were prone to hepatocarcinogenesis and had a phenotype similar to that of DDX20 deficiency, suggesting that miRNA-140 plays a central role in DDX20 deficiency-related pathogenesis. Conclusion: These results indicate that miRNA-140 acts as a liver tumor suppressor, and that impairment of miRNA-140 function due to a deficiency of DDX20, a miRNA machinery component, could lead to hepatocarcinogenesis. (HEPATOLOGY 2013; 57: 162-170)

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  • MicroRNA-140 acts as a liver tumor suppressor by controlling NF-κB activity by directly targeting DNA methyltransferase 1 (Dnmt1) expression. 国際誌

    Akemi Takata, Motoyuki Otsuka, Takeshi Yoshikawa, Takahiro Kishikawa, Yohko Hikiba, Shuntaro Obi, Tadashi Goto, Young Jun Kang, Shin Maeda, Haruhiko Yoshida, Masao Omata, Hiroshi Asahara, Kazuhiko Koike

    Hepatology (Baltimore, Md.)   57 ( 1 )   162 - 70   2013年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    UNLABELLED: MicroRNAs (miRNAs) are small RNAs that regulate the expression of specific target genes. While deregulated miRNA expression levels have been detected in many tumors, whether miRNA functional impairment is also involved in carcinogenesis remains unknown. We investigated whether deregulation of miRNA machinery components and subsequent functional impairment of miRNAs are involved in hepatocarcinogenesis. Among miRNA-containing ribonucleoprotein complex components, reduced expression of DDX20 was frequently observed in human hepatocellular carcinomas, in which enhanced nuclear factor-κB (NF-κB) activity is believed to be closely linked to carcinogenesis. Because DDX20 normally suppresses NF-κB activity by preferentially regulating the function of the NF-κB-suppressing miRNA-140, we hypothesized that impairment of miRNA-140 function may be involved in hepatocarcinogenesis. DNA methyltransferase 1 (Dnmt1) was identified as a direct target of miRNA-140, and increased Dnmt1 expression in DDX20-deficient cells hypermethylated the promoters of metallothionein genes, resulting in decreased metallothionein expression leading to enhanced NF-κB activity. MiRNA-140-knockout mice were prone to hepatocarcinogenesis and had a phenotype similar to that of DDX20 deficiency, suggesting that miRNA-140 plays a central role in DDX20 deficiency-related pathogenesis. CONCLUSION: These results indicate that miRNA-140 acts as a liver tumor suppressor, and that impairment of miRNA-140 function due to a deficiency of DDX20, a miRNA machinery component, could lead to hepatocarcinogenesis.

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  • A genome-wide association study of HCV-induced liver cirrhosis in the Japanese population identifies novel susceptibility loci at the MHC region 査読 国際誌

    Urabe Y, Ochi H, Kato N, Kumar V, Takahashi A, Muroyama R, Hosono N, Otsuka M, Tateishi R, Lo P. H, Tanikawa C, Omata M, Koike K, Miki D, Abe H, Kamatani N, Toyota J, Kumada H, Kubo M, Chayama K, Nakamura Y, Matsuda K

    J Hepatol   58 ( 5 )   875 - 82   2013年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Current status of miRNA-targeting therapeutics and preclinical studies against gastroenterological carcinoma. 査読

    Shibata C, Otsuka M, Kishikawa T, Yoshikawa T, Ohno M, Takata A, Koike K

    Molecular and cellular therapies   1   5   2013年

  • Regulation of the expression of the liver cancer susceptibility gene MICA by microRNAs 査読

    Takahiro Kishikawa, Motoyuki Otsuka, Takeshi Yoshikawa, Motoko Ohno, Akemi Takata, Chikako Shibata, Yuji Kondo, Masao Akanuma, Haruhiko Yoshida, Kazuhiko Koike

    Scientific Reports   3   2739   2013年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Hepatocellular carcinoma (HCC) is a threat to public health worldwide. We previously identified the association of a single nucleotide polymorphism (SNP) at the promoter region of the MHC class I polypeptide-related sequence A (MICA) gene with the risk of hepatitis-virus-related HCC. Because this SNP affects MICA expression levels, regulating MICA expression levels may be important in the prevention of HCC. We herein show that the microRNA (miR) 25-93-106b cluster can modulate MICA levels in HCC cells. Overexpression of the miR 25-93-106b cluster significantly suppressed MICA expression. Conversely, silencing of this miR cluster enhanced MICA expression in cells that express substantial amounts of MICA. The changes in MICA expression levels by the miR25-93-106b cluster were biologically significant in an NKG2D-binding assay and an in vivo cell-killing model. These data suggest that the modulation of MICA expression levels by miRNAs may be a useful method to regulate HCCs during hepatitis viral infection.

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  • Silencing of microRNA-122 enhances interferon-α signaling in the liver through regulating SOCS3 promoter methylation. 査読

    Yoshikawa T, Takata A, Otsuka M, Kishikawa T, Kojima K, Yoshida H, Koike K

    Scientific reports   2   637   2012年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • A miRNA machinery component DDX20 controls NF-κB via microRNA-140 function. 査読

    Takata A, Otsuka M, Yoshikawa T, Kishikawa T, Kudo Y, Goto T, Yoshida H, Koike K

    Biochemical and biophysical research communications   420 ( 3 )   564 - 569   2012年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:3  

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  • Altered composition of fatty acids exacerbates hepatotumorigenesis during activation of the phosphatidylinositol 3-kinase pathway 査読

    Yotaro Kudo, Yasuo Tanaka, Keisuke Tateishi, Keisuke Yamamoto, Shinzo Yamamoto, Dai Mohri, Yoshihiro Isomura, Motoko Seto, Hayato Nakagawa, Yoshinari Asaoka, Motohisa Tada, Miki Ohta, Hideaki Ijichi, Yoshihiro Hirata, Motoyuki Otsuka, Tsuneo Ikenoue, Shin Maeda, Shuichiro Shiina, Haruhiko Yoshida, Osamu Nakajima, Fumihiko Kanai, Masao Omata, Kazuhiko Koike

    JOURNAL OF HEPATOLOGY   55 ( 6 )   1400 - 1408   2011年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Background & Aims: Some clinical findings have suggested that systemic metabolic disorders accelerate in vivo tumor progression. Deregulation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway is implicated in both metabolic dysfunction and carcinogenesis in humans; however, it remains unknown whether the altered metabolic status caused by abnormal activation of the pathway is linked to the protumorigenic effect.
    Methods: We established hepatocyte-specific Pik3ca transgenic (Tg) mice harboring N1068fs*4 mutation.
    Results: The Tg mice exhibited hepatic steatosis and tumor development. PPAR gamma-dependent lipogenesis was accelerated in the Tg liver, and the abnormal profile of accumulated fatty acid (FA) composition was observed in the tumors of Tg livers. In addition, the Akt/mTOR pathway was highly activated in the tumors, and in turn, the expression of tumor suppressor genes including Pten, Xpo4, and Dlc1 decreased. Interestingly, we found that the suppression of those genes and the enhanced in vitro colony formation were induced in the immortalized hepatocytes by the treatment with oleic acid (OA), which is one of the FAs that accumulated in tumors.
    Conclusions: Our data suggest that the unusual FA accumulation has a possible role in promoting in vivo hepato-tumorigenesis under constitutive activation of the PI3K pathway. The Pik3ca Tg mice might help to elucidate molecular mechanisms by which metabolic dysfunction contributes to in vivo tumor progression. (C) 2011 European Association for the Study of the Liver. Published by Elsevier B. V. All rights reserved.

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  • Direct differentiation of hepatic cells from human induced pluripotent stem cells using a limited number of cytokines 査読

    Akemi Takata, Motoyuki Otsuka, Tomomi Kogiso, Kentaro Kojima, Takeshi Yoshikawa, Ryosuke Tateishi, Naoya Kato, Shuichiro Shiina, Haruhiko Yoshida, Masao Omata, Kazuhiko Koike

    HEPATOLOGY INTERNATIONAL   5 ( 4 )   890 - 898   2011年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Purpose Development of improved protocols for differentiating induced pluripotent stem (iPS) cells into hepatic cells is an important step toward their use in the field of hepatology. Specifically, the number of different cytokines should be reduced to limit undesired effects and to reduce the cost of the process. In this report, we describe a simple method for directing human iPS cells to differentiate into hepatic cells using only two cytokines and a short incubation time.
    Methods A two-step protocol for differentiating iPS cells into hepatic cells was developed. A high dose of activin A was applied for 3 days to induce definitive endoderm formation. Subsequently, cells were treated with hepatocyte growth factor (HGF) for 5 days to generate hepatic cells. Differentiation was confirmed by immunostaining for differentiation markers. Albumin mRNA levels in differentiated hepatic cells generated using a previously tested three-step protocol that uses activin A, fibroblast growth factor (FGF)/bone morphogenetic protein (BMP), and HGF, and our new protocol were compared to determine the efficiency of differentiation.
    Results Our two-step protocol induced the differentiation of iPS cells into hepatic cells and required a shorter differentiation period than the previous three-step protocol. The differentiation efficiencies of the two protocols were comparable and the induced hepatic cells were functional.
    Conclusions Developing efficient induction and culture methods to generate more highly matured hepatocytes is essential for regenerative cell-based therapies. Our protocol provides a simple, cost-effective, and time-saving approach for generating hepatic cells from iPS cells.

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  • Receptor for Activated Protein Kinase C: Requirement for Efficient MicroRNA Function and Reduced Expression in Hepatocellular Carcinoma 査読

    Motoyuki Otsuka, Akemi Takata, Takeshi Yoshikawa, Kentaro Kojima, Takahiro Kishikawa, Chikako Shibata, Mutsuhiro Takekawa, Haruhiko Yoshida, Masao Omata, Kazuhiko Koike

    PLOS ONE   6 ( 9 )   2011年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PUBLIC LIBRARY SCIENCE  

    MicroRNAs (miRNAs) are important regulators of gene expression that control physiological and pathological processes. A global reduction in miRNA abundance and function is a general trait of human cancers, playing a causal role in the transformed phenotype. Here, we sought to newly identify genes involved in the regulation of miRNA function by performing a genetic screen using reporter constructs that measure miRNA function and retrovirus-based random gene disruption. Of the six genes identified, RACK1, which encodes "receptor for activated protein kinase C" (RACK1), was confirmed to be necessary for full miRNA function. RACK1 binds to KH-type splicing regulatory protein (KSRP), a member of the Dicer complex, and is required for the recruitment of mature miRNAs to the RNA-induced silencing complex (RISC). In addition, RACK1 expression was frequently found to be reduced in hepatocellular carcinoma. These findings suggest the involvement of RACK1 in miRNA function and indicate that reduced miRNA function, due to decreased expression of RACK1, may have pathologically relevant roles in liver cancers.

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  • MicroRNA-22 and microRNA-140 suppress NF-κB activity by regulating the expression of NF-κB coactivators. 査読

    Takata A, Otsuka M, Kojima K, Yoshikawa T, Kishikawa T, Yoshida H, Koike K

    Biochemical and biophysical research communications   411 ( 4 )   826 - 831   2011年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:4  

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  • HCV関連肝細胞癌患者の高齢化と非硬変肝からの発癌の増加

    吉田 晴彦, 建石 良介, 佐藤 雅哉, 三神 信太郎, 内野 康史, 新野 徹, 榎奥 健一郎, 後藤 絵里子, 中川 隼人, 増崎 良太, 浅岡 良成, 大塚 基之, 山敷 宣代, 五藤 忠, 椎名 秀一朗, 小俣 政男, 小池 和彦

    肝臓   52 ( Suppl.1 )   A411 - A411   2011年4月

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    記述言語:日本語   出版者・発行元:(一社)日本肝臓学会  

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  • Reduced expression of RAS protein activator like-1 in gastric cancer 査読

    Motoko Seto, Miki Ohta, Tsuneo Ikenoue, Takafumi Sugimoto, Yoshinari Asaoka, Motohisa Tada, Dai Mohri, Yotaro Kudo, Hideaki Ijichi, Keisuke Tateishi, Motoyuki Otsuka, Yoshihiro Hirata, Shin Maeda, Kazuhiko Koike, Masao Omata

    INTERNATIONAL JOURNAL OF CANCER   128 ( 6 )   1293 - 1302   2011年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-BLACKWELL  

    RAS signaling is frequently deregulated in human neoplasms. However, RAS mutations have been found in only a small proportion of human gastric cancers, implicating other mechanisms in the activation of RAS signaling in gastric tumorigenesis. We have previously reported that decreased expression of RAS protein activator like-1 (RASAL1), a member of the RAS-GTPase-activating proteins that switch off RAS activity, contributes to colon tumor progression. In our study, we explored the involvement of decreased RASAL1 expression in gastric tumorigenesis. RASAL1 expression was reduced in 6 of 10 gastric cancer cell lines examined by immunoblotting. Knockdown of RASAL1 increased mitogen-activated protein kinase signaling in response to growth factor stimulation, and the forced expression of RASAL1 reduced proliferation of gastric cancer cells. Immunohistochemical analyses in primary gastric tumors showed that RASAL1 expression was reduced in 23 of 48 (48%) of the gastric cancers but in none of the adenomas (0/10). Methylation of the RASAL1 promoter region and loss of heterozygosity (LOH) at the RASAL1 locus were examined to investigate the causes of RASAL1 silencing. All cell lines with reduced RASAL1 had RASAL1 methylation, and two had LOH. In primary gastric cancers, methylation or LOH was detected in 50% (6/12) of those with reduced RASAL1. Furthermore, RASAL1 expression was restored in some cell lines by histone deacetylase inhibitor treatment. Our findings demonstrate that reduced RASAL1 expression, partly due to genetic and epigenetic changes, contributes to gastric carcinogenesis, and also re-emphasize the importance of RAS signaling in gastric cancer development.

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  • Epithelial p38 alpha Controls Immune Cell Recruitment in the Colonic Mucosa 査読

    Young Jun Kang, Motoyuki Otsuka, Arjen van den Berg, Lixin Hong, Zhe Huang, Xiurong Wu, Duan-Wu Zhang, Bruce A. Vallance, Peter S. Tobias, Jiahuai Han

    PLOS PATHOGENS   6 ( 6 )   e1000934   2010年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PUBLIC LIBRARY SCIENCE  

    Intestinal epithelial cells (IECs) compose the first barrier against microorganisms in the gastrointestinal tract. Although the NF-kappa B pathway in IECs was recently shown to be essential for epithelial integrity and intestinal immune homeostasis, the roles of other inflammatory signaling pathways in immune responses in IECs are still largely unknown. Here we show that p38 alpha in IECs is critical for chemokine expression, subsequent immune cell recruitment into the intestinal mucosa, and clearance of the infected pathogen. Mice with p38 alpha deletion in IECs suffer from a sustained bacterial burden after inoculation with Citrobacter rodentium. These animals are normal in epithelial integrity and immune cell function, but fail to recruit CD4(+) T cells into colonic mucosal lesions. The expression of chemokines in IECs is impaired, which appears to be responsible for the impaired T cell recruitment. Thus, p38 alpha in IECs contributes to the host immune responses against enteric bacteria by the recruitment of immune cells.

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  • DDX20 deficiency enhances NF-kappa B by impairing NF-kappa B suppressive-microRNA function and leads to hepatocarcinogenesis 査読

    Takata Akemi, Otsuka Motoyuki, Kudo Yotaro, Kojima Kentaro, Maeda Shin, Tateishi Keisuke, Ikenoue Tsuneo, Ijichi Hideaki, Hirata Yoshihiro, Yoshida Haruhiko, Omata Masao, Koike Kazuhiko

    CANCER RESEARCH   70   2010年4月

  • Apoptosis Signal-Regulating Kinase 1 Regulates Colitis and Colitis-Associated Tumorigenesis by the Innate Immune Responses 査読

    Yoku Hayakawa, Yoshihiro Hirata, Hayato Nakagawa, Kei Sakamoto, Yohko Hikiba, Motoyuki Otsuka, Hideaki Ijichi, Tsuneo Ikenoue, Keisuke Tateishi, Masao Akanuma, Keiji Ogura, Haruhiko Yoshida, Hidenori Ichijo, Masao Omata, Shin Maeda

    GASTROENTEROLOGY   138 ( 3 )   1055 - U334   2010年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:W B SAUNDERS CO-ELSEVIER INC  

    BACKGROUND & AIMS: Mitogen-activated protein kinase (MAPK) signaling pathways regulate multiple cellular functions and are implicated in the pathogenesis of inflammatory bowel disease and colitis-associated cancer (CAC). Apoptosis signal-regulating kinase 1 (ASK1) is a MAPK kinase kinase; little is known about the role of ASK1 in colonic disease. We assessed the involvement of ASK1 in the development of intestinal inflammation and CAC. METHODS: Dextran sodium sulfate (DSS) or Citrobacter rodentium was used to induce colitis in wildtype (WT) and ASK1 knock-out (ASK1(-/-)) mice; CAC was induced by azoxymethane injection followed by repeated intake of DSS by the mice. Primary macrophages were isolated from WT and ASK1(-/-) mice and used to investigate the involvement of ASK1 in innate immune responses. Bone marrow chimeric mice were used to study the contribution of myeloid cells to colitis activity. RESULTS: ASK1 deficiency increased susceptibility to colonic inflammation in both models of colitis. In vitro, ASK1(-/-) macrophages were impaired in their ability to kill bacteria and had increased susceptibility to bacterial-induced apoptosis, because p38 was inactivated. Expression of antiapoptotic genes was greatly reduced in ASK1(-/-) macrophages. WT mice given transplants of ASK1(-/-) mouse-derived bone marrow cells developed more severe DSS-induced colitis than mice with WT-derived bone marrow cells. In the CAC model, ASK1(-/-) mice developed more numerous and larger tumors than WT mice through increased colonic inflammation. CONCLUSIONS: ASK1 controls the development of intestinal inflammation and CAC through the regulation of innate immunity.

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  • TNF-alpha stimulation inhibits siRNA-mediated RNA interference through a mechanism involving poly-(A) tail stabilization. 査読

    Mols J, van den Berg A, Otsuka M, Zheng M, Chen J, Han J

    Biochimica et biophysica acta   1779   712 - 719   2008年11月

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    出版者・発行元:11  

    DOI: 10.1016/j.bbagrm.2008.03.007

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  • TNF-alpha stimulation inhibits siRNA-mediated RNA interference through a mechanism involving poly-(A) tail stabilization 査読

    Johann Mols, Arjen van den Berg, Motoyuki Otsuka, Min Zheng, Jianming Chen, Jiahuai Han

    BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS   1779 ( 11 )   712 - 719   2008年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    The control of mRNA stability is a complex biological process that involves numerous factors, including rnicroRNA (miRNA) and short interfering RNA (siRNA). Here, we show that short interfering RNA (siRNA) and rnicroRNA share some similarities in their response to cellular stress. rniR16 expedites the degradation of mRNAs containing AU-rich elements (ARE) in their 31 untranslated region (UTR). si20 is an siRNA designed to target a non-ARE sequence in the TNF 3&apos;UTR. We found that both si20 and miR16/ARE-mediated degradation of mRNAs can be inhibited by stimulating cells with different stresses. By analyzing TNF-alpha stimulation-mediated stabilization of si20- and miR16-targeted mRNA, we show that this stabilization is not caused by modifying si20 and miR16 loading into Ago2 complexes, or mRNA targeting to Ago2, but by inhibiting mRNA deadenylation. This is the first report showing that a specific siRNA-mediated mRNA degradation can be regulated by inflammatory stimuli, and that deadenylation is involved in this siRNA-mediated mRNA decay. (C) 2008 Elsevier B.V. All rights reserved.

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  • Potential contribution of tumor suppressor p53 in the host defense against hepatitis C virus 査読

    Narayan Dharel, Naoya Kato, Ryosuke Muroyama, Hiroyoshi Taniguchi, Motoyuki Otsuka, Yue Wang, Amarsanaa Jazag, Run-Xuan Shao, Jin-Hai Chang, Mark K. Adler, Takao Kawabe, Masao Omata

    HEPATOLOGY   47 ( 4 )   1136 - 1149   2008年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JOHN WILEY & SONS INC  

    Infection by hepatitis C virus (HCV) usually results into chronic hepatitis that can ultimately lead to cirrhosis and hepatocellular carcinoma. Type 1 interferons (IFN-alpha/beta) constitute the primary cellular defense against viral infection including HCV. IFN binding to their receptors activates associated Jak1 and Tyk2 kinases, which ultimately leads to phosphorylation and assembly of a signal transducer and activator of transcription protein (STAT)1-STAT2-interferon regulatory factor (IRF)9 trimetric complex called interferon-stimulated gene factor 3 that translocates into the nucleus and binds to the interferon-stimulated response elements (ISRE), leading to transcriptional induction of several antiviral genes, including double-stranded RNA-activated protein kinase (PKR), 2',5'-oligoadenylate synthetase (OAS), and myxovirus resistance protein A (MxA). Understanding the mechanisms of how the virus evades this cellular innate defense and establishes a chronic infection is the key for the development of better therapeutics against HCV infection. Here, we demonstrate that p53 could have a crucial role in the cellular innate defense against HCV. We observed significantly higher levels of HCV RNA replication and viral protein expression in the Huh7 cells when their p53 expressions were knocked down. Moreover, IFN treatment was less effective in inhibiting the HCV RNA replication in the p53-knocked-down (p53kd) Huh? cells. In fact, the activation of the ISRE and the induction of ISGs were significantly attenuated in the p53kd Huh? cells and p53 was found to directly interact with IRF9. Conclusion: These observations underscore the potential contributions of the tumor suppressor p53 in cellular antiviral immunity against HCV with possible therapeutic implications.

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  • Macrophage deletion of p38 alpha partially impairs lipopolysaccharide-induced cellular activation 査読

    Young Jun Kang, Jianming Chen, Motoyuki Otsuka, Johann Mols, Shuxun Ren, Yinbin Wang, Jiahuai Han

    JOURNAL OF IMMUNOLOGY   180 ( 7 )   5075 - 5082   2008年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER ASSOC IMMUNOLOGISTS  

    The activation of p38 alpha, a MAPK family member, is associated with macrophage activation by microbial pattern molecules, such as LPS. The requirement of p38 alpha in inflammatory responses has been shown in a number of studies using chemical inhibitors, though the inhibitors also inhibit p38 beta and perhaps some other enzymes. In this study, we used conditional knockout of p38 alpha in macrophages to address the role of p38 alpha in macrophage activation. We found that p38 alpha deficiency causes a significant inhibition in the production of LPS-induced TNF-alpha, IL-12, and IL-18, but it has little or no effect on IL-6 or IFN-beta production. Knockout of p38a in macrophages did not affect LPS-induced activation of the other major signaling pathways (NF-kappa B, Jnk, and Erk), nor did it affect the transcriptional activity of NF-kappa B. It had little inhibitory effect on LPS-induced AP-1 activity, but it significantly inhibited LPS-induced C/EBP-beta and CREB activation, indicating that the role of p38 alpha in cytokine production in macrophages is at least in part through its regulation of C/EBP-beta and CREB activation. In addition, we also confirmed that p38 alpha is important for phagocytosis of bacteria by macrophages. Our in vivo studies with two murine models showed that p38 alpha is involved in sepsis. Collectively, our data demonstrate that p38 alpha is an important player in inflammatory responses.

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  • Calcineurin negatively regulates TLR-Mediated activation pathways 査読

    Young Jun Kang, Brenda Kusler, Motoyuki Otsuka, Michael Hughes, Nobutaka Suzuki, Shinobu Suzuki, Wen-Chen Yeh, Shizuo Akira, Jiahuai Han, Patricia P. Jones

    JOURNAL OF IMMUNOLOGY   179 ( 7 )   4598 - 4607   2007年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER ASSOC IMMUNOLOGISTS  

    In innate immunity, microbial components stimulate macrophages to produce antimicrobial substances, cytokines, other proinflammatory mediators, and IFNs via TLRs, which trigger signaling pathways activating NF-kappa B, MAPKs, and IFN response factors. We show in this study that, in contrast to its activating role in T cells, in macrophages the protein phosphatase calcineurin negatively regulates NF-kappa B, MAPKs, and IFN response factor activation by inhibiting the TLR-mediated signaling pathways. Evidence for this novel role for calcineurin was provided by the findings that these signaling pathways are activated when calcineurin is inhibited either by the inhibitors cyclosporin A or FK506 or by small interfering RNA-targeting calcineurin, and that activation of these pathways by TLR ligands is inhibited by the overexpression of a constitutively active form of calcineurin. We further found that I kappa B-alpha degradation, MAPK activation, and TNF-alpha production by FK506 were reduced in macrophages from mice deficient in MyD88, Toll/IL-1R domain-containing adaptor-inducing IFN-beta (TRIF), TLR2, or TLR4, whereas macrophages from TLR3-deficient or TLR9 mutant mice showed the same responses to FK506 as those of wild-type cells. Biochemical studies indicate that calcineurin interacts with MyD88, TRIF, TLR2, and TLR4, but not with TLR3 or TLR9. Collectively, these results suggest that calcineurin negatively regulates TLR-mediated activation pathways in macrophages by inhibiting the adaptor proteins MyD88 and TRIF, and a subset of TLRs.

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  • Interferon-beta is activated by hepatitis C virus NS5B and inhibited by NS4A, NS4B, and NS5A 査読

    Masaru Moriyama, Naoya Kato, Motoyuki Otsuka, Run-Xuan Shao, Hiroyoshi Taniguchi, Takao Kawabe, Masao Omata

    HEPATOLOGY INTERNATIONAL   1 ( 2 )   302 - 310   2007年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Innate immunity is part of the antiviral response. Interferon (IFN)-beta plays a leading role in this system. To investigate the influence of hepatitis C virus (HCV) on innate immunity, we examined the effect of viral proteins on IFN-beta induction. HepG2 cells were co-transfected with plasmids for seven HCV proteins (core protein, NS2, NS3, NS4A, NS4B, NS5A, and NS5B) and the IFN-beta promoter luciferase. Toll-like receptor (TLR) 3 and Toll/IL-1 receptor domain-containing adapter inducing IFN-beta (TRIF) play key roles in dsRNA-mediated activation of interferon regulatory factor (IRF)-3 and IFN-beta; therefore, the participation of TLR3/TRIF in NS5B-mediated IFN induction was examined. Among seven HCV proteins, only NS5B, a viral RNA-dependent RNA polymerase (RdRp), activated the IFN-beta promoter. However, mutant NS5B without RdRp activity or template/primer association did not activate the IFN-beta promoter. Activation of the IFN-beta promoter by NS5B required the positive regulatory domain III, a binding sequence for IRF-3. Moreover, IRF-3 was phosphorylated by NS5B. Both inhibition of TLR3 expression by small interfering RNA and expression of the dominant negative form of TRIF significantly reduced NS5B-induced activation of IFN-beta. Of the six other HCV proteins, NS4A, NS4B, and NS5A efficiently inhibited this activation. HCV NS5B is a potent activator of the host innate immune system, possibly through TLR3/TRIF and synthesis of dsRNA. Meanwhile, NS4A, NS4B, and NS5A block IFN-beta induction by NS5B, which may contribute toward the persistence of this virus.

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  • Gene expressions associated with chemosensitivity in human hepatoma cells 査読

    Yujin Hoshida, Masaru Moriyama, Motoyuki Otsuka, Naoya Kato, Hiroyoshi Taniguchi, Yasushi Shiratori, Naohiko Seki, Masao Omata

    HEPATO-GASTROENTEROLOGY   54 ( 74 )   489 - 492   2007年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:H G E UPDATE MEDICAL PUBLISHING S A  

    Background/Aims: Only limited patients with hepatoma. benefit from chemotherapy without a clear explanation. We aimed to identify genes associated with chemosensitivity using transcriptional profiles. Methodology: In 8 hepatoma cells (HLE, HLF, Huh7, Hep3B, PLC/PRF/5, SK-Hep1, Huh6, and HepG2) transcriptional profiles were obtained using cDNA microarray including 2,300 genes. Chemosensitivities to 8 anticancer drugs (nimustine, mitomycin C, cisplatin, carboplatin, doxorubicin, epirubicin, mitoxantrone, and 5-fluorouracil) were measured by obtaining 50% growth inhibitory concentrations (GI50) using MTT assay. Genes having drug-specific association with chemosensitivity were selected. Results: Up-regulation of topoisomerase II beta was associated with chemo-resistance, the target of doxorubicin. Platinum-specific resistance was associated with superoxide dismutase 2 expression. Antigen peptide transporter I expression correlated with nimustine and mitoxantrone-specific susceptibility. These results were verified by semi-quantitative RT-PCR. Drug inactivators reported in non-liver cancers such as multidrug transporters and drug metabolizers showed less diversity of chemosensitivity in hepatoma cells. Conclusions: To evaluate these gene expressions may be useful to select anticancer drugs, and possibly to consider new therapeutic target to modify drug action.

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  • Absence of tyrosine kinase mutations in Japanese colorectal cancer patients 査読

    R-X Shao, N. Kato, L-J Lin, R. Muroyama, M. Moriyama, T. Ikenoue, H. Watabe, M. Otsuka, B. Guleng, M. Ohta, Y. Tanaka, S. Kondo, N. Dharel, J-H Chang, H. Yoshida, T. Kawabe, M. Omata

    ONCOGENE   26 ( 14 )   2133 - 2135   2007年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    Tyrosine kinases, which are important regulators of intracellular signal-transduction pathways, have mutated forms that are often associated with oncogenesis and are attractive targets for therapeutic intervention. Recently, systematic mutational analyses of tyrosine kinases revealed that a minimum of 30% of colorectal cancer contain at least one mutation in the tyrosine kinases. To further explore these mutations, we examined all reported mutations of NTRK3, FES, KDR, EPHA3, NTRK2, JAK1, PDGFRA, EPHA7, EPHA8, ERBB4, FGFR1, MLK4 and GUCY2F genes in the 24 colorectal cancer cell lines. Unexpectedly, among 24 colorectal cancer cell lines, only two cell lines (LoVo and CaR1) harbored mutation C1408T (R470C) in MLK4 gene. The mutation rate was extremely low compared to that previously reported. Therefore, we analyzed mutations in 46 colorectal cancer samples resected from the same number of Japanese patients. Surprisingly, none of the 46 samples contained any of the mutations reported. Based on our study, we advise that a more comprehensive tyrosine kinase gene mutation assay is necessary in the future.

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  • Nucleotide change of codon 38 in the X gene of hepatitis B virus genotype C is associated with an increased risk of hepatocellular carcinoma 査読

    Ryosuke Muroyama, Naoya Kato, Haruhiko Yoshida, Motoyuki Otsuka, Masaru Moriyama, Yue Wang, Run-Xuan Shao, Narayan Dharel, Yasuo Tanaka, Miki Ohta, Ryosuke Tateishi, Shuichiro Shiina, Masashi Tatsukawa, Kenichi Fukai, Fumio Imazeki, Osamu Yokosuka, Yasushi Shiratori, Masao Omata

    JOURNAL OF HEPATOLOGY   45 ( 6 )   805 - 812   2006年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Background/Aims: The hepatitis B virus (HBV) genotype C is associated with the development of hepatocellular carcinoma (HCC). In addition, the HBV X gene, which encodes the pleiotropic transactivator HBx, has also been associated with the development of HCC. In this study, we investigated whether nucleotide changes in the X gene of genotype C are associated with the development of HCC.
    Methods/Results: We sequenced the X gene in age- and sex-matched 39 HBV-infected patients with HCC and 36 HBV-infected patients without HCC. A novel nucleotide change that resulted in a proline to serine substitution at codon 38 in HBx (codon-38 change) was preferentially found in patients with HCC. Then, sera were collected from a new group of age- and sex-matched 52 patients with HCC and 51 patients without HCC. In this cohort also, the codon-38 change was associated with HCC. Multiple logistic regression analysis showed the prevalence of the codon-38 change was significantly associated with HCC in all patients (P = 0.001, odds ratio: 4.89).
    Conclusion: The codon-38 change in genotype C is an independent risk factor for the development of HCC and may serve as a useful molecular marker for predicting the clinical outcomes in patients infected with HBV. (c) 2006 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

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  • Hepatitis C virus core protein is a potent inhibitor of RNA silencing-based antiviral response 査読

    Y Wang, N Kato, A Jazag, N Dharel, M Otsuka, H Taniguchi, T Kawabe, M Omata

    GASTROENTEROLOGY   130 ( 3 )   883 - 892   2006年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:W B SAUNDERS CO-ELSEVIER INC  

    Background & Aims: Persistent infection with hepatitis C virus (HCV) leads to chronic hepatitis and hepatocellular carcinoma (HCC). RNA interference (RNAi) may act as a host antiviral response against viral RNA. Methods: The effects of RNAi on both the replicative intermediates and the internal ribosome entry site (IRES) of HCV were studied by using HCV-related short interfering RNA (siRNA) detection assay. The mechanism that permits HCV to escape RNAi was studied by using RNAi assay materials. Results: These studies demonstrate that the Dicer, an RNase enzyme that generates short siRNA, can target and digest both the IRES and the replicative intermediate of HCV into siRNA of similar to 22 nucleotides. Further studies also show that Dicer can inhibit the replication of the HCV subgenomic replicon. However, the HCV core protein inhibits this RNAi and rescues the replication of the HCV subgenomic replicon through a direct interaction with Dicer. Conclusions: RNAi is a limiting factor for HCV infection, and the core protein suppresses the RNA silencing-based antiviral response. This ability of the core protein to counteract the host defense may lead to a persistent viral infection and may contribute to the pathogenesis of HCV.

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  • Identifying genes with differential expression in gemcitabine-resistant pancreatic cancer cells using comprehensive transcriptome analysis 査読

    Y Nakai, M Otsuka, Y Hoshida, M Tada, Y Komatsu, T Kawabe, M Omata

    ONCOLOGY REPORTS   14 ( 5 )   1263 - 1267   2005年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PROFESSOR D A SPANDIDOS  

    Pancreatic cancer is often unresectable at diagnosis, and chemotherapy using gemcitabine is now the standard treatment for advanced pancreatic cancer. However, acquired resistance to gemcitabine resulting in therapeutic failure is often encountered. Therefore, we sought to identify genes that determine gemcitabine resistance by evaluating the relationship between gene expression profiles and gemcitabine sensitivity to provide molecular targets for overcoming gemcitabine resistance. First, the gemcitabine concentration needed for 50% growth inhibition was examined in six pancreatic cancer cell lines. By exposing MIA PaCa-2 cells to long-term gemcitabine, we established gemcitabine-resistant cells. The gene expression profiles of the six pancreatic cancer cell lines and gemcitabine-resistant cells were determined using cDNA microarray analysis. By comparing the results, 30 genes were identified as differentially expressed genes correlated with gemcitabine sensitivity. Differentially expressed genes in the parental cell lines were also examined, and six overlapping genes were identified as genes correlated with gemcitabine sensitivity in both assays. Of these genes, the down-regulated expression of TNFSF6 protein, also known as Fas ligand, was confirmed in the gemcitabine-resistant cell line. These results should provide therapeutic molecular targets for overcoming gemcitabine resistance.

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  • Large-scale search of single nucleotide polymorphisms for hepatocellular carcinoma susceptibility genes in patients with hepatitis C 査読

    N Kato, GJ Ji, Y Wang, M Baba, Y Hoshida, M Otsuka, H Taniguchi, M Moriyama, N Dharel, T Goto, RX Shao, T Matsuura, K Ishii, S Shiina, T Kawabe, M Muramatsu, M Omata

    HEPATOLOGY   42 ( 4 )   846 - 853   2005年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JOHN WILEY & SONS INC  

    Hepatitis C virus (HCV) infection is a major risk factor for developing hepatocellular carcinoma (HCC). The host genetic factors that are involved in the development of HCC in patients with HCV infection remain to be investigated. To search for single nucleotide polymorphisms (SNPs) in HCC susceptibility genes, 393 SNPs in 171 candidate genes were examined in 188 Japanese patients with chronic HCV infection, including 77 patients with HCC. HCC-related SNPs were then examined in another 188 patients (including 93 patients with HCC) with chronic HCV infection. Haplotype analyses of HCC-related genes were performed in a total of 376 patients. Of the 393 SNPs, 31 SNPs in 29 genes were significantly associated with HCC based on an initial screening (P &lt; .05). Of these 31 SNPs, 3 SNPs of 3 genes (SCYB14, GFRAI, and CRHR2) were significantly associated with HCC in a secondary screening. Haplotype analyses of these 3 genes identified 2 haplotype blocks associated with HCC. In conclusion, these SNPs and haplotypes located in the SCBY14, CRHR2, and GFRA1 genes will be used as markers to identify a subgroup of Japanese patients with chronic HCV infection who are at high risk of developing HCC.

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  • NF-kappa B and ERK-signaling pathways contribute to the gene expression induced by cag PAI-positive-Helicobacter pylori infection 査読

    Wataru Shibata, Yoshihiro Hirata, Haruhiko Yoshida, Motoyuki Otsuka, Yujin Hoshida, Keiji Ogura, Shin Maeda, Tomoya Ohmae, Ayako Yanai, Yuzo Mitsuno, Naohiko Seki, Takao Kawabe, Masao Omata

    WORLD JOURNAL OF GASTROENTEROLOGY   11 ( 39 )   6134 - 6143   2005年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:BAISHIDENG PUBL GRP CO LTD  

    AIM: To elucidate the sequential gene expression profile in AGS cells co-cultured with wild-type Helicobacter pylori (H pylori) as a model of H pylori-infected gastric epithelium, and to further examine the contribution of cag-pathogenicity islands (cagPAI)-coding type IV secretion system and the two pathways, nuclear factor kappa B (NF-kappa B) and extracellular signal-regulated kinases (ERK) on wild-type H pylori-induced gene expression.
    METHODS: Gene expression profiles induced by H pylori were evaluated in AGS gastric epithelial cells using cDNA microarray, which were present in the 4 600 independent clones picked up from the human gastric tissue. We also analyzed the contribution of NF-kappa B and ERK signaling on H pylori-induced gene expression by using inhibitors of specific signal pathways. The isogenic mutant with disrupted cagE (Delta cagE) was used to elucidate the role of cagPAI-encoding type IV secretion system in the gene expression profile.
    RESULTS: According to the expression profile, the genes were classified into four clusters. Among them, the clusters characterized by continuous upregulation were most conspicuous, and it contained many signal transducer activity-associated genes. The role of cagPAI on cultured cells was also investigated using isogenic mutant cagE, which carries non-functional cagPAI. Then the upregulation of more than 80% of the induced genes (476/566) was found to depend on cagPAI. Signal transducer pathway through NF-kappa B or ERK are the major pathways which are known to be activated by cagPAI-positive H pylori. The role of these pathways in the whole signal activation H pylori was analyzed. The specific inhibitors against NF-kappa B or ERK pathway blocked the activation of gene expression in 65% (367/566) or 76% (429/566) of the genes whose activation appealed to depend on cagPAI.
    CONCLUSION: These results suggest that more than half of the genes induced by cagPAI-positive H pylori depend on NF-kappa B and ERK signaling activation, and these pathways may play a role in the gene expression induced by host-bacterial interaction which may associate with H pylori-related gastro-duodenal diseases. (C) 2005 The WJG Press and Elsevier Inc. All rights reserved.

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  • No mutations in the tyrosine kinases of human hepatic, pancreatic, and gastric cancer cell lines 査読

    RX Shao, M Otsuka, N Kato, JH Chang, R Muroyama, H Taniguchi, M Moriyama, Y Wang, T Kawabe, M Omata

    JOURNAL OF GASTROENTEROLOGY   40 ( 9 )   918 - 918   2005年9月

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    記述言語:英語   出版者・発行元:SPRINGER TOKYO  

    DOI: 10.1007/s00535-005-1661-5

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  • Hepatitis C virus core protein and hepatitis activity are associated through transactivation of interleukin-8 査読

    Y Hoshida, N Kato, H Yoshida, Y Wang, M Tanaka, T Goto, M Otsuka, H Taniguchi, M Moriyama, F Imazeki, O Yokosuka, T Kawabe, Y Shiratori, M Omata

    JOURNAL OF INFECTIOUS DISEASES   192 ( 2 )   266 - 275   2005年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:UNIV CHICAGO PRESS  

    Background. We evaluated the association between variations in hepatitis C virus (HCV) core protein and hepatitis severity in patients with chronic HCV infection who achieved remission without viral eradication and had a biochemical response to interferon (IFN) therapy, to evaluate the effect of HCV core sequence in the absence of the influence of host factors.
    Methods. Using serum from 10 patients with a biochemical response and 10 patients with no response, we measured serum levels of interleukin (IL)-1 beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IFN-gamma, and tumor necrosis factor-alpha before and after IFN therapy. Expression vectors with the core region were transfected into Huh7 cells, and cytokine induction was evaluated by reporter assay.
    Results. In biochemical responders, only IL-8 levels decreased after IFN therapy (P = .04). Changes in the C-terminal hydrophobic region were observed more frequently in biochemical responders. Activation of the IL-8 promoter by HCV core protein was significantly decreased in biochemical responders after IFN therapy (P = .04). When 69 C-terminal amino acids from before IFN therapy were replaced with those from after IFN therapy in 3 biochemical responders, their ability to transactivate IL-8 decreased.
    Conclusions. Differences in amino acids in the HCV core protein correlates with hepatitis activity through the modulation of IL-8 induction in HCV-infected patients.

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  • Interaction between the HCVNS3 protein and the host TBK1 protein leads to inhibition of cellular antiviral responses 査読

    M Otsuka, N Kato, M Moriyama, H Taniguchi, Y Wang, N Dharel, T Kawabe, M Omata

    HEPATOLOGY   41 ( 5 )   1004 - 1012   2005年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JOHN WILEY & SONS INC  

    The persistent nature of hepatitis C virus (HCV) infection suggests that HCV encodes proteins that enable it to overcome host antiviral responses. Toll-like receptor 3 (TLR3)-mediated signaling, which recognizes the double-stranded RNA that is produced during viral replication and induces type I interferons, including interferon beta (IFN-beta), is crucial to the host defense against viruses. Recent studies suggest that a TIR domain-containing adaptor protein, TRIF, and two protein kinases, TANK-binding kinase-1 (TBK1) and I kappa B kinase-epsilon (IKK epsilon), play essential roles in TLR3-mediated IFN-beta production through the activation of the transcriptional factor interferon regulatory factor 3 (IRF-3). We report that the HCV NS3 protein interacts directly with TBK1, and that this binding results in the inhibition of the association between TBK1 and IRF-3, which leads to the inhibition of IRF-3 activation. In conclusion, these results suggest the mechanisms of the inhibition of the innate immune responses of HCV infection by NS3 protein.

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  • Hepatic gene expression profiles associated with fibrosis progression and hepatocarcinogenesis in hepatitis C patients 査読

    Run-Xuan Shao, Yujin Hoshida, Motoyuki Otsuka, Naoya Kato, Ryosuke Tateishi, Takuma Teratani, Shuichiro Shiina, Hiroyoshi Taniguchi, Masaru Moriyama, Takao Kawabe, Masao Omata

    WORLD JOURNAL OF GASTROENTEROLOGY   11 ( 13 )   1995 - 1999   2005年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:BAISHIDENG PUBL GRP CO LTD  

    AIM: To determine fibrosis progression and hepatocellular carcinoma (HCC), using simultaneous gene expression analysis.
    METHODS: Total RNA samples were extracted from liver biopsies from 19 patients with hepatitis C virus (HCV) infection and 3 patients without HCV infection. Among the 19 HCV-infected patients, 7 and 12 patients had grade F1-2 and F3-4 fibrosis, respectively. Of the 12 patients with F3-4 fibrosis, 8 had HCC. Gene expression in the liver samples was determined using an oligonucleotide microarray. The following comparisons were performed: normal livers vs HCV-infected livers; F1-2 vs F3-4; and F3-4 with HCC vs F3-4 without HCC. Genes that were differentially expressed between these groups were identified based on signal-to-noise ratios.
    RESULTS: In the HCV-infected livers, genes involved in immune responses were highly expressed. Expression levels of genes for plasma proteins and drug-metabolizing enzymes were decreased and those of genes involved in the cell cycle and oncogenesis were increased in the F3-4 cases as compared to the F1-2 cases. Among the F3-4 cases, genes involved in carbohydrate metabolism tended to be more highly expressed in patients with HCC than in patients without HCC.
    CONCLUSION: We identified genes that are associated with fibrosis progression and hepatocarcinogenesis. This information may be used to detect increased carcinogenic potential in the livers of patients with HCV infection. (C) 2005 The WJG Press and Elsevier Inc. All rights reserved.

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  • Vitamin K2 binds 17 beta-hydroxysteroid dehydrogenase 4 and modulates estrogen metabolism 査読

    M Otsuka, N Kato, T Ichimura, S Abe, Y Tanaka, H Taniguchi, Y Hoshida, M Moriyama, Y Wang, RX Shao, D Narayan, R Muroyama, F Kanai, T Kawabe, T Isobe, M Omata

    LIFE SCIENCES   76 ( 21 )   2473 - 2482   2005年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Vitamin K is a cofactor for gamma-glutamyl carboxylase, an enzyme that is important for blood coagulation. Recent studies have shown that vitamin K has other roles, in addition to post-transcriptional modification, such as bone metabolism and antitumoral actions; these findings have indicated that there might be unknown intracellular binding proteins that are specific for vitamin K. In this study, vitamin K-binding proteins were characterized by pull-down experiment using a chemically synthesized biotynylated vitamin K followed by mass spectrometric identification of the pull-downed components. The results indicated that 17 beta hydroxy steroid dehydrogenase 4, apolipoportein E, and 40S ribosomal proteins S7 and S13 might be the candidates of the vitamin K-binding proteins. Subsequent experiments showed that vitamin K2 binds 17 beta hydroxysteroid dehydrogenase 4 and decreases the intracellular estradiol:estrone ratio, which resulted in the inhibition of the amount of estrogen receptor alpha-binding to its target DNA. These results suggest a. possible novel role for vitamin K in modulating estrogen function. (c) 2005 Elsevier Inc. All rights reserved.

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  • Acyclic retinoid inhibits human hepatoma cell growth by suppressing fibroblast growth factor-mediated signaling pathways 査読

    RX Shao, M Otsuka, N Kato, H Taniguchi, Y Hoshida, M Moriyama, T Kawabe, M Omata

    GASTROENTEROLOGY   128 ( 1 )   86 - 95   2005年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:W B SAUNDERS CO  

    Background& Aims: Hepatocellular carcinoma (HCC) is one of the most common human malignancies. Its high mortality rate is mainly a result of high intrahepatic recurrence. The novel synthetic retinoid acyclic retinoid (ACR) has been reported to prevent the recurrence of human HCC after surgical resection of primary tumors, but the molecular mechanisms underlying its effects remain to be elucidated. In this study, we clarified the molecular targets of ACR. Methods: The inhibitory effects by ACR on growth were examined. Intracellular signaling induced by ACR was comprehensively studied by a reporter assay. Gene expression changes by ACR were examined using a microarray. From these results, a candidate signaling pathway modulated by ACR was determined and whether antagonizing this pathway reverses the effect was examined. Results: We show that ACR inhibits the growth of HCC cells through the down-regulation of fibroblast growth factor (FGF) receptor 3 expression and FGF-mediated signaling, which in turn suppresses the activity of Rho and serum response factor-mediated transcription. Conversely, overexpression of the active form of FGF receptor 3 or the addition of FGF reverses the ACR-mediated inhibition of growth. In addition, silencing the FGF receptor 3 gene by RNA interference inhibits cell growth. Conclusions: These studies show that ACR is a potent inhibitor of FGF signaling and that selective blocking of the FGFmediated pathway could be a promising therapeutic approach for the management of patients with HCC.

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  • A simple combination of serum type IV collagen and prothrombin time to diagnose cirrhosis in patients with chronic active hepatitis C 査読

    Y Qiu, YJ Hoshida, N Kato, M Moriyama, M Otsuka, H Taniguchi, T Kawabe, M Omata

    HEPATOLOGY RESEARCH   30 ( 4 )   214 - 220   2004年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCI IRELAND LTD  

    Background/aim: Cirrhosis in chronic hepatitis C is a major cause of mortality. The components of reported diagnostic indices of cirrhosis based on biochemical markers may be modified by therapies for hepatic inflammation. We aimed to construct index of cirrhosis in patients treated for chronic active hepatitis.
    Methods: Using sera of consecutive 140 patients with chronic hepatitis C, routine blood tests including fibrosis markers, type IV collagen and procollagen type III peptide (PIIIP), were performed. Diagnosis of cirrhosis was determined by biopsy. Using multivariate analyses, diagnostic indices of cirrhosis were constructed.
    Results: Fifty-eight patients were diagnosed to have cirrhosis. Platelet count, prothrombin time, and albumin were lower, and type IV collagen and PIIIP were higher in patients with cirrhosis (p &lt; 0.05). There was no difference in aspartate and alanine aminotransferases (AST, ALT) and gamma-glutamyl-transpeptidase (GGT) (p &gt; 0.3). Our diagnostic indices I (prothrombin time and platelet count) and II (prothrombin time and type IV collagen) of cirrhosis showed the area under the ROC curves (AUC) of 0.77 and 0.81, respectively. The index II was relatively superior to the index I.
    Conclusions: Using combination of type IV collagen and prothrombin time, efficient diagnosis of cirrhosis can be performed in patients with chronic active hepatitis C. (C) 2004 Elsevier B.V. All rights reserved.

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  • Genes associated with human hepatocellular carcinoma cell chemosensitivity to 5-fluorouracil plus interferon-alpha combination chemotherapy 査読

    M Moriyama, Y Hoshida, N Kato, M Otsuka, H Yoshida, T Kawabe, M Omata

    INTERNATIONAL JOURNAL OF ONCOLOGY   25 ( 5 )   1279 - 1287   2004年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PROFESSOR D A SPANDIDOS  

    Recently, combined chemotherapy with 5-fluorouracil (5-FU) and interferon (IFN)-alpha has been reported to show marked effects in patients with advanced hepatocellular carcinoma. We investigated the genes associated with susceptibility to this combination therapy. The gene expression profiles of eight human hepatocellular carcinoma cells (HepG2, Hep3B, Huh7, Huh6, PLC/PRF/5, HLE, HLF, and SK-Hep1) were evaluated using an oligonucleotide microarray that consisted of 3,800 genes. The 50% growth inhibitory concentration (GI50) values for 5-FU, IFN-alpha, and the combination of 5-FU plus IFN-a were determined by the MTT assay. We selected genes that were expressed differentially between the cells with increased susceptibility to the combination therapy and the remaining cells. Relevance networks of the gene expression patterns and GI50 values of the susceptible cells were constructed to find genes associated with susceptibility to the combination therapy. Of the eight cells tested, five showed increased susceptibility to 5-FU plus IFN-alpha compared with 5-FU treatment alone. Among the 3,800 genes, 25 were expressed differentially between susceptible cells and resistant cells. The relevance networks revealed that sensitivity to 5-FU plus IFN-a involved the expression of 27 independent genes, which included 10 genes that are commonly associated with sensitivity to 5-FU alone. We selected a set of genes to predict susceptibility to 5-FU plus IFN-alpha combination therapy. We also selected genes that play key roles in the synergistic effect of this combination therapy. These gene sets should prove useful in evaluations of the efficacy and underlying molecular mechanisms of this combination therapy.

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  • Vitamin K-2 inhibits the growth and invasiveness of hepatocellular carcinoma cells via protein kinase A activation 査読

    M Otsuka, N Kato, RX Shao, Y Hoshida, H Ijichi, Y Koike, H Taniguchi, M Moriyama, Y Shiratori, T Kawabe, M Omata

    HEPATOLOGY   40 ( 1 )   243 - 251   2004年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JOHN WILEY & SONS INC  

    Hepatocellular carcinoma (HCC) is a common human malignancy. Its high mortality rate is mainly a result of high intrahepatic recurrence and portal venous invasion (PVI). We previously reported that the development of PVI is related to levels of des-gamma-carboxy prothrombin (DCP), a serum protein that increases at a notably higher rate in patients with HCC. Because DCP is produced by a vitamin K shortage, we examined the biological effects of extrinsic supplementation of vitamin K-2 in HCC cells in vitro and in vivo. Consequently, vitamin K-2 inhibits the growth and invasion of HCC cells through the activation of protein kinase A, which modulates the activities of several transcriptional factors and inhibits the small GTPase Rho, independent of suppression of DCP. In addition, administration of vitamin K-2 to nude mice inoculated with liver tumor cells reduced both tumor growth and body weight loss. In conclusion, similar to an acyclic retinoid-which was previously reported to prevent the recurrence of HCC-vitamin K-2, another lipid-soluble vitamin, may be a promising therapeutic means for the management of HCC.

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  • UDP-glucuronosyltransferase 1A7 genetic polymorphisms are associated with hepatocellular carcinoma in Japanese patients with hepatitis C virus infection 査読

    Y Wang, N Kato, Y Hoshida, M Otsuka, H Taniguchi, M Moriyama, S Shiina, T Kawabe, YM Ito, M Omata

    CLINICAL CANCER RESEARCH   10 ( 7 )   2441 - 2446   2004年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER ASSOC CANCER RESEARCH  

    Purpose: Genetic polymorphisms of UDP-glucuronosyl-transferase 1A7 (UGT1A7), which detoxifies endogenous and environmental carcinogens, have been reported to be associated with hepatocellular carcinoma (HCC) in German populations. On the other hand, we reported that interleukin-1beta (IL-1beta) gene polymorphisms were associated with hepatitis C virus (HCV)-related HCC. In this study, we evaluated the association of both genes with the risk of HCC in Japanese HCV-infected patients.
    Experimental Design: Genetic polymorphisms of UGT1A7 and IL-1beta were investigated in 280 Japanese patients (122 with HCC and 158 without HCC) with chronic HCV infections, by use of standard PCR-based genotyping techniques.
    Results: We designated the UGT1A7*1 allele (a haplotype conferring higher activity) as H and the *2, *3, and *4 alleles (haplotypes conferring lower activity) as L. The proportions of UGT1A7 L/L and H/L alleles (genotypes) in patients with HCC (25% and 45%, respectively) were higher than those in patients without HCC (15% and 39%, respectively) with odds ratios of 2.73 (95% confidence interval, 1.40-5.35) and 1.80 (95% confidence interval, 1.05-3.09), respectively, compared with the UGT1A7 H/H alleles. Multivariate analyses revealed that UGT1A7 L/L and IL-1beta/-31T/T-511C/C genotypes, the presence of cirrhosis, age 60 years, male sex, and alpha-fetoprotein &gt;20 mug/ml were associated with the presence of HCC (odds ratios, 2.33, 2.67, 4.20, 3.12, 3.09, and 2.90, respectively).
    Conclusion: The UGT1A7 polymorphisms together with IL-1beta were associated with the presence of HCC in Japanese HCV-infected patients.

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  • Smad4-independent regulation of p21/WAF1 by transforming growth factor-beta 査読

    H Ijichi, M Otsuka, K Tateishi, T Ikenoue, T Kawakami, F Kanai, Y Arakawa, N Seki, K Shimizu, K Miyazono, T Kawabe, M Omata

    ONCOGENE   23 ( 5 )   1043 - 1051   2004年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    The transforming growth factor-beta (TGF-beta)-Smad signaling pathway inhibits the growth of human epithelial cells and plays a role in tumor suppression. The Smad4 gene is mutated or deleted in 50% of pancreatic cancers. In this study, the Smad4-null pancreatic cancer cell line BxPC-3 was transfected with either the Smad4 expression vector or the empty vector and incubated in the presence or absence of TGF-beta. The cells were analysed using a cDNA microarray, which included 2280 named genes to screen for target genes regulated by TGF-beta in either a Smad4-dependent or -independent manner. The microarray and subsequent quantitative RT-PCR analysis demonstrated that the Smad4-independent and -dependent signaling pathways driven by TGF-beta upregulated only one of the 2280 genes, respectively, suggesting that Smad4-independent signaling downstream of TGF-beta might be as widespread as Smad4-dependent signaling. In this study, we demonstrated that the cyclin-dependent kinase inhibitor p21/WAF1, which has been considered the major effector of the Smad-dependent growth inhibitory signal of TGF-beta, is upregulated in a Smad4-independent manner. The upregulation occurs through Smad2/3-dependent transcriptional activation of the p21/WAF1 promoter region. These results suggest a novel mechanism of gene regulation, that is, a novel signal mediator other than Smad4.

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  • Hepatitis C virus core protein upregulates transforming growth factor-beta 1 transcription 査読

    H Taniguchi, N Kato, M Otsuka, T Goto, H Yoshida, Y Shiratori, M Omata

    JOURNAL OF MEDICAL VIROLOGY   72 ( 1 )   52 - 59   2004年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-LISS  

    The majority of persons with chronic hepatitis C virus (HCV) infection develop liver fibrosis. Transforming growth factor (TGF)-beta1 plays a pivotal role in the pathogenesis of post-inflammatory liver scarring. To clarify the influence of HCV infection on liver fibrosis, a reporter assay was used to investigate the effect of viral proteins on TGF-beta1 expression in human hepatoma cells. Of all HCV proteins investigated (core, E1/E2/p7, NS2, NS3, NS4A, NS4B, NS5A, and NS5B), only the core protein activated the TGF-beta1 promoter and upregulated TGF-beta1 expression measured by an RNase protection assay. Bases -376 to -331 by in the promoter region of TGF-beta1 are responsible for upregulation by HCV core protein, and the nuclear protein that binds to this region increased with the stimulation of HCV core protein. Blocking the mitogen-activated protein kinase pathway prevented upregulation of TGF-beta1 by HCV core protein. The immunological response is supposed to be a major factor to cause the secretion of TGF-beta1 from non-parenchymal cells, but the results suggest that the HCV core protein expression may upregulate directly TGF-beta1 transcription in parenchymal cells and suggest a new paradigm for exacerbation of liver fibrosis by HCV infection.

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  • Antiapoptotic regulation by hepatitis C virus core protein through up-regulation of inhibitor of caspase-activated DNase 査読

    R Sacco, T Tsutsumi, R Suzuki, M Otsuka, H Aizaki, S Sakamoto, M Matsuda, N Seki, Y Matsuura, T Miyamura, T Suzuki

    VIROLOGY   317 ( 1 )   24 - 35   2003年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    The hepatitis C virus (HCV) core protein is considered to influence multiple cellular processes. We developed a human hepatoblastoma HepG2-derived inducible cell line, Hep191, which allows tightly regulated expression of the core protein at relatively low but physiological levels under control of the ecdysone-regulated promoter. By transcriptional profiling, we identified differentially expressed genes, some of which are involved in cell growth or apoptosis such as inhibitor of caspase-activated DNase (ICAD), defender against cell death 1, tumor necrosis factor (TNF) receptor 1, and cytochrome c oxidase subunit VIII. Furthermore, we found that core protein expression increases a steady-state level of ICAD protein, possibly through enhancing its promoter activity, and inhibits caspase-3 activity induced by anti-Fas antibody. Since Fas- or TNF-mediated DNA fragmentation is suppressed in the core-induced Hep191 cells, these findings suggest that expression of HCV core at physiological levels confers blocking activity of caspase-activated DNase and consequently inhibiting apoptotic cell death. (C) 2003 Elsevier Inc. All rights reserved.

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  • Comparing gene expression profiles in human liver, gastric, and pancreatic tissues using full-length-enriched cDNA libraries 査読

    M Otsuka, M Arai, M Mori, M Kato, N Kato, O Yokosuka, T Ochiai, M Takiguchi, M Omata, N Seki

    HEPATOLOGY RESEARCH   27 ( 1 )   76 - 82   2003年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCI IRELAND LTD  

    In the post-genome-sequencing era, full-length cDNA-sequence resources are extremely useful for functional analyses of genes. In addition, comprehensive gene profiling of human tissues at the mRNA level is also useful in understanding the molecular mechanisms of tissue-specific functions and disease pathogenesis. In this study, to obtain a wide variety of full-length cDNA clones derived from digestive tissues, numerous expressed sequence tags were generated from libraries enriched with full-length cDNAs. In total, 13 575 sequences were obtained from three cDNA libraries, which were constructed from tissues and cell lines of human liver, stomach, and pancreas. The integration of overlapping clones categorized the sequences into 5936 clusters (1666, 2746, and 2222 clusters in the liver, stomach, and pancreas, respectively). Of these, 1138 clones were scored as full-length cDNAs. Surprisingly, the redundant clones from all three tissues were assembled to show that only 101 genes (1.7% of the assembled 5936 genes) were shared. These results suggest that functional differences between tissues are probably related to their divergent gene expression profiles, and form a basis for understanding the molecular mechanisms underlying tissue-specific pathogenesis that are expressed in different organs. In addition, the full-length cDNAs obtained in this study should prove useful for future functional analyses of the genes expressed in digestive tissues. (C) 2003 Elsevier B.V. All rights reserved.

    DOI: 10.1016/S1386-6346(03)0161-X

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  • 肝細胞癌患者血清のプロテオミクス解析 査読

    星田 有人, 川上 高幸, 大塚 基之, 谷口 寿章, 西村 信一郎, 小尾 俊太郎, 椎名 秀一朗, 川邊 隆夫, 小俣 政男

    肝臓   44 ( Suppl.1 )   A174 - A174   2003年4月

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    記述言語:日本語   出版者・発行元:(一社)日本肝臓学会  

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  • Synergistic activation of the serum response element-dependent pathway by hepatitis B virus X protein and large-isoform hepatitis delta antigen 査読

    T Goto, N Kato, H Yoshida, M Otsuka, M Moriyama, Y Shiratori, K Koike, M Matsumura, M Omata

    JOURNAL OF INFECTIOUS DISEASES   187 ( 5 )   820 - 828   2003年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:UNIV CHICAGO PRESS  

    Hepatitis delta virus (HDV) is a naturally occurring satellite of hepatitis B virus (HBV). There are few studies of the effects of the combination of HBV and HDV proteins (HDV antigens [HDAgs]) on intracellular signaling pathways. To understand the influence of HBV and HDV coinfection on hepatocytes, we investigated the effect of HBV proteins and HDAgs on the serum response element (SRE)-dependent pathway. Reporter assays revealed that only HBV X protein (HBx), alone or with the large isoform of HDAg (LHDAg), synergistically activated the SRE-dependent pathway. The effect of HBx and LHDAg on Elk1 or serum response factor (SRF) was examined, because both proteins bind to the SRE. HBx activated the transcriptional ability of Elk1, whereas LHDAg activated the transcriptional ability of SRF. Thus, HBx and LHDAg synergistically activated the SRE-dependent pathway. These results may help us understand clinical phenomena in patients coinfected with HBV and HDV.

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  • Liver chip and gene shaving 査読

    M Otsuka, Y Hoshida, N Kato, M Moriyama, H Taniguchi, M Arai, M Mori, N Seki, M Omata

    JOURNAL OF GASTROENTEROLOGY   38   89 - 92   2003年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER-VERLAG TOKYO  

    A comprehensive profile of genes expressed at the mRNA level in various human tissues is considered to be important for understanding the molecular mechanisms of the tissue-specific function and the pathogenesis of related diseases. Here, the gene expression profiling in three human digestive tissues, liver, stomach, and pancreas, was catalogued by generating a large number of expressed sequence tags, and clarified how quantitatively the gene expressions are different. After assembling the redundant clones among three tissues, the results showed that only 1.7% among the assembled genes was expressed commonly in the investigated tissues. These results suggest that the significant functional divergences in different tissues must be related to the divergence of the gene expression profiles. Recently, microarray technologies are widely used. Considering the results that different genes express in different tissues, however, it is important to spot the cDNAs derived from the same tissues or cells examined to acquire information efficiently. For the study of digestive diseases, we constructed an in-house microarray by using the cDNA sets derived from the digestive tissues (liver and gastric chip). In addition, because the amount of information acquired by the microarray analyses is huge, the power of bioinformatics for unifying the obtained data is indispensable. Some examples of the strategies for handling the microarray data obtained by our in-house microarrays are shown in this article.

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  • Study of digestive diseases in post-genome era 査読

    Masao Omata, Motoyuki Otsuka, Takayuki Kawakami, Yujin Hoshida

    Japanese Journal of Gastroenterology   100 ( 2 )   135 - 143   2003年2月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:2  

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  • Relevance network between chemosensitivity and transcriptome in human hepatoma cells 査読

    M Moriyama, Y Hoshida, M Otsuka, S Nishimura, N Kato, T Goto, H Taniguchi, Y Shiratori, N Seki, M Omata

    MOLECULAR CANCER THERAPEUTICS   2 ( 2 )   199 - 205   2003年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER ASSOC CANCER RESEARCH  

    Generally, hepatoma is not a chemosensitive tumor, and the mechanism of resistance to anticancer drugs is not fully elucidated. We aimed to comprehensively evaluate the relationship between chemosensitivity and gene expression profile in human hepatoma cells, by using microarray analysis, and analyze the data by constructing relevance networks.
    In eight hepatoma cell lines (HLE, HLF, Huh7, Hep3B, PLC/PRF/5, SK-Hep1, Huh6, and HepG2), the baseline expression levels of 2300 genes were measured by cDNA microarray. The concentrations of eight anticancer drugs (nimustine, mitomycin C, cisplatin, carboplatin, doxorubicin, epirubicin, mitoxantrone, and 5-fluorouracil) needed for 50% growth inhibition were examined and used as a measure of chemosensitivity. These data were combined and comprehensive pair-wise correlations between gene expression levels and the 50% growth inhibition values were calculated. Significant correlations with significance were used to construct networks of similarity.
    Fifty-two relations, including 42 genes, were selected. Among them, nearly 20% were various types of transporters, and most of them negatively correlated with chemosensitivity. Transporter associated with antigen processing 1 was associated with resistance to mitoxantrone, consistent with previous reports. Other transporters were not reported previously to associate with chemosensitivity. Resistance to doxorubicin and its analogue, epirubicin, were positively correlated with topoisomerase II beta expression, whereas it negatively correlated with expression of carboxypeptidases A3 and Z. Response to nimustine was associated with expression of superoxide dismutase 2.
    Relevance networks identified several negative correlations between gene expression and resistance, which were missed by hierarchical clustering. Our results suggested the necessity of systematically evaluating the transporting systems that may play a major role in resistance in hepatoma. This may provide useful information to modify anticancer drug action in hepatoma.

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  • Interieukin-1 beta gene polymorphisms associated with hepatocellular carcinoma in hepatitis C virus infection 査読

    Y Wang, N Kato, Y Hoshida, H Yoshida, H Taniguchi, T Goto, M Moriyama, M Otsuka, S Shiina, Y Shiratori, Y Ito, M Omata

    HEPATOLOGY   37 ( 1 )   65 - 71   2003年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:W B SAUNDERS CO  

    Hepatitis C virus (HCV) infection is a major risk factor for developing hepatocellular carcinoma (HCC), a life-threatening sequel. However, the factors that affect disease progression to HCC have not been thoroughly elucidated. Genetic polymorphisms in proinflammatory cytokines, the interleukin 1 (IL-1) family (IL-1beta and IL-1ra) and tumor necrosis factor-alpha (TNF-alpha), were studied in 274 Japanese patients with chronic HCV infection and 55 healthy individuals using standard polymerase chain reaction-based genotyping techniques. The association between these polymorphisms and disease status was evaluated while controlling for confounding clinical variables. The proportion of patients with HCC in the IL-1beta-31 T/T (55%, odds ratio to C/C was 2.63, P =.009) genotype was higher than in the T/C (44%, odds ratio to C/C was 1.64, P =.149) and C/C genotypes (35%). The IL-1beta-31 and -511 loci were in near complete linkage disequilibrium, and the IL-1beta-511/-31 haplotype C-T was significantly associated with the presence of HCC (odds ratio of 1.5 1, P =.02). Polymorphisms in the TNF-alpha gene were not associated with disease. A multivariate analysis revealed that the IL-1beta-31 T/T genotype, alpha-fetoprotein &gt;20 mug/L, presence of cirrhosis, male sex, and age &gt; 60 years were associated with the presence of HCC at odds ratios of 3.73 (T/T vs. C/C), 4.12, 4.03, 3.89, and 3.27, respectively. In conclusion, the IL-1beta-31 genotype T/T or the IL-1beta-511/-31 haplotype C-T is associated with the presence of HCC in Japanese patients with chronic HCV infection.

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  • Differential cellular gene expression induced by hepatitis B and C viruses 査読

    M Otsuka, H Aizaki, N Kato, T Suzuki, T Miyamura, M Omata, N Seki

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   300 ( 2 )   443 - 447   2003年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Hepatitis B virus (HBV) is a hepatotropic virus that causes acute and chronic hepatocellular injury and hepatocellular carcinoma. To clarify how HBV proteins regulate host cellular gene expression, we used our in-house cDNA microarray and HepG2.2.15 cells, which are derived from HepG2 cells and produce all HBV proteins. Of 2304 genes investigated, several genes were differentially expressed in HepG2.2.15 cells compared with HepG2 cells. These genes included insulin-like growth factor II and alpha-fetoprotein, consistent with previous reports. Furthermore. we previously performed similar microarray analyses to clarify the effects of hepatitis C virus (HCV) proteins on host cells, using a HepG2-derivative cell line, which produces all HCV proteins. Using these two microarray results, we compared the differences in cellular gene expression induced by HBV and HCV proteins. The expression of the majority of genes investigated differed only slightly between HBV and HCV protein-producing cells. However, HBV and HCV proteins clearly regulated several genes in a reciprocal manner. Combined, these microarray results shed new light on the effects of HBV proteins on cellular gene expression and on the differences in the pathogenic activities of these two hepatitis viruses. (C) 2002 Elsevier Science (USA). All rights reserved.

    DOI: 10.1016/S0006-291X(02)02861-9

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  • Signals induced by HCV proteins 査読

    M Otsuka, N Kato, H Taniguchi, H Yoshida, Y Shiratori, M Omata

    HCV/OXIDATIVE STRESS AND LIVER DISEASE   32 - 47   2003年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPRINGER-VERLAG TOKYO  

    Hepatitis C virus (HCV) causes a persistent infection, chronic hepatitis, cirrhosis, and hepatocellular carcinoma. To explore the influence of HCV infection on hepatocytes, the effects of HCV proteins on intracellular signal transduction pathways, especially those related to apoptosis, fibrosis, and cell growth, were investigated. The effects of nine HCV proteins (core, NS2, NS3, NS4A, NS4B, NS5A, and NS5B) on the CRE-, SRE-, NFB-, AP-1-, SRF-, ISRE-, HSE-, GRE-, and p53-associated pathways were investigated by use of a reporter assay. The effects of core protein on apoptosis were examined by DNA laddering and Western blotting after induction of apoptosis by Fas stimulation. The possible mechanisms of anti-apoptotic effects of core protein were investigated by RNase protection assay and a reporter assay. The effects of HCV proteins on TGF beta production were determined by a reporter assay. Among seven HCV proteins investigated, core protein had the strongest influence on intracellular signaling, especially for the SRE-, AP-1-, NFkappaB-, and p53-associated pathways. Core protein promoted Bcl-x(L) expression through the mitogen-activated protein kinase (MAPK) pathway and inhibited apoptosis. Among HCV proteins, only core protein caused TGF beta promoter activity through the MAPK pathway. From these results, core protein was considered to regulate cell growth exquisitely in hepatocytes, inhibit apoptosis, and promote liver fibrosis directly without any inflammation or the mediation of any other cells. These functions may reflect the direct action of HCV proteins on the intracellular signal transduction pathways related to chronic hepatitis pathogenesis.

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  • [HCV-related hepatocellular carcinoma]. 査読

    Otsuka M, Kato N, Yoshida H, Yoshida H, Shiratori Y, Omata M

    Uirusu   52 ( 2 )   295 - 300   2002年12月

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    記述言語:日本語   出版者・発行元:2  

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    その他リンク: http://search.jamas.or.jp/link/ui/2003167214

  • Expression profiling of liver cell lines expressing entire or parts of hepatitis C virus open reading frame 査読

    H Aizaki, T Harada, M Otsuka, N Seki, M Matsuda, YW Li, H Kawakami, Y Matsuura, T Miyamura, T Suzuki

    HEPATOLOGY   36 ( 6 )   1431 - 1438   2002年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:W B SAUNDERS CO  

    Although hepatitis C virus (HCV) is a causative agent of liver diseases, its mechanism of pathogenesis is still unclear, mainly because of the lack of adequate cell culture systems to support HCV infection and replication. In this report, we describe development and characterization of human hepatoma cell lines constitutively expressing entire (Hep394) or parts (Hep352, Hep3294) of the HCV open reading frame (ORF). The viral and cellular proteolytic machinery involved in the viral precursor processing was consistently functional, and processed HCV proteins were synthesized in these established cell lines. By using a cDNA microarray analysis coupled with semiquantitative reverse-transcription polymerase chain reaction (RT-PCR), we identified 12 genes up-regulated and 4 genes down-regulated in Hep394 cells. With regard to genes related to cell growth regulation, we found up-regulation of forkhead transcription factor FREAC-1, poly (A) binding protein PABP2,, and Ras suppressor Rsu-1. Another category of changes in gene expression includes MHC antigens, which play an important role in the T-cell-mediated immune reaction in the liver. In conclusion, functional genomic approaches comparing expression among the different cell lines expressing parts of the HCV genome may promote our understanding of the molecular basis of pathogenicity of HCV infection.

    DOI: 10.1053/jhep.2002.36937

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  • Identification of candidate genes for Sjögren's syndrome using MRL/lpr mouse model of Sjögren's syndrome and cDNA microarray analysis. 査読

    Azuma T, Takei M, Yoshikawa T, Nagasugi Y, Kato M, Otsuka M, Shiraiwa H, Sugano S, Mitamura K, Sawada S, Masuho Y, Seki N

    Immunology letters   81 ( 3 )   171 - 176   2002年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:3  

    DOI: 10.1016/S0165-2478(01)00344-3

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  • Hepatitis C virus core protein inhibits apoptosis via enhanced Bcl-x(L) expression 査読

    M Otsuka, N Kato, H Taniguchi, H Yoshida, T Goto, Y Shiratori, M Omata

    VIROLOGY   296 ( 1 )   84 - 93   2002年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Previous studies indicated that hepatitis C virus core protein influences cellular apoptosis. However, the precise mechanisms of the effects are not fully understood. Therefore, in this study, we examined the mechanisms of the effects on cell apoptosis by core protein, using transiently transfected and magnetically collected core-producing HepG2 cells. First, to elucidate the target site of core protein in the apoptotic pathway, we examined the activation of caspases after anti-Fas antibody stimulation. Core protein inhibited the apoptotic cascade downstream from caspase 8 and upstream from caspase 3. Next, to clarify more direct mechanisms of this effect, mRNA levels of several bcl-2-related genes were examined. An RNase protection assay showed that the mRNA of bcl-xl increased in the core-producing cells. We showed that this increase was mediated by the enhancement of bcl-x promoter activity by core protein through an extracellular-regulated kinase pathway. These results suggest that core protein inhibits apoptosis at the mitochondria level through augmentation of Bcl-x expression, resulting in an inhibition of caspase 3 activation. (C) 2002 Elsevier Science (USA).

    DOI: 10.1006/viro.2002.1371

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  • The evaluation of putative virulence factors of Helicobacter pylori for gastroduodenal disease by use of a short-term Mongolian gerbil infection model 査読

    M Akanuma, S Maeda, K Ogura, Y Mitsuno, Y Hirata, T Ikenoue, M Otsuka, T Watanabe, Y Yamaji, H Yoshida, T Kawabe, Y Shiratori, M Omata

    JOURNAL OF INFECTIOUS DISEASES   185 ( 3 )   341 - 347   2002年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:UNIV CHICAGO PRESS  

    Few virulence determinants of Helicobacter pylori have been tested in vivo. We conducted this study to establish an animal model for their screening. Six-week-old male Mongolian gerbils were inoculated with wild-type H. pylori (TN2) or its isogenic mutant with deletion of cagE (TN2DeltacagE), total cag pathogenicity island (TN2Deltacag PAI), HP0499 (TN2DeltaHP499), or HP0638 (TN2DeltaHP638) (n = 5 each). The animals were killed 3 weeks later, and the density of bacteria and the degree of inflammation in the stomach were compared. Infection was established in all animals except those inoculated with TN2DeltaHP638. TN2 and TN2DeltaHP499, but not TN2DcagE and TN2Deltacag PAI, induced intense inflammation, although the densities of bacteria were similar. The Mongolian gerbil model was useful for the screening of virulence determinants in vivo, which confirmed the importance of cag PAI while questioning that of HP0499.

    DOI: 10.1086/338772

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  • Identification of genes associated with sensitivity to 5-fluorouracil and cisplatin in hepatoma cells 査読

    Y Hoshida, M Moriyama, M Otsuka, N Kato, T Goto, H Taniguchi, Y Shiratori, N Seki, M Omata

    JOURNAL OF GASTROENTEROLOGY   37   92 - 95   2002年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER-VERLAG TOKYO  

    Background. The prognosis of patients with advanced hepatoma is grim. Although chemotherapy is adapted to such patients, the efficacy is low and the outcome cannot be predicted before therapy. In this study, we aimed to identify genes associated with sensitivity to 5-fluorouracil and cisplatin, drugs widely used in treatment, using gene expression profiles. Methods: Gene expression was evaluated in eight human hepatoma cell lines using an in-house cDNA microarray including 2300 known genes. The 50% growth inhibitory concentrations (Gl(50)) of 5-fluorouracil and cisplatin were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and designated as chemosensitivity. Genes with expression ratios associated with Gl(50) were selected using the permutation test. Results: For 5-fluorouracil and cisplatin, 21 and 40 genes, respectively, were selected. From among the genes associated with 5-fluorouracil and cisplatin, several encoding metabolic enzymes were selected. In addition, several genes involved in the cell cycle and transcription were identified. Conclusions: We identified genes that may be associated with sensitivity to 5-fluorouracil and cisplatin. A list of these genes may be useful to elucidate how these drugs work on human hepatoma.

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  • Induction of proliferation-related signals by hepatitis C virus 査読

    N Kato, H Yoshida, M Otsuka, Y Shiratori, M Omata

    GROWTH, PROLIFERATION, AND APOPTOSIS IN HEPATOCYTES   81 - 98   2002年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPRINGER-VERLAG TOKYO  

    Hepatitis C virus (HCV) causes persistent infection, chronic hepatitis, cirrhosis, and hepatocellular carcinoma. To explore the influence of HCV infection on hepatocytes, the effects of HCV proteins on intracellular signal transduction pathways were investigated. The effects of seven HCV proteins (core, nonstructural [NS]2, NS3, NS4A, NS4B, NS5A, and NS5B) on cyclic AMP response element (CRE)-, serum response element (SRE)-, nuclear factor (NF)-kappaB-, activator protein (AP)-1-, serum response factor (SRF)-, and p53-associated pathways were investigated by use of a reporter assay. The activation of signals by HCV proteins was examined using a reporter plasmid with an interleukin (IL)-8 or p21(waf1) promoter. The possible mechanisms by which HCV proteins activate these pathways were investigated. Among the seven HCV proteins investigated, core protein had the strongest influence on intracellular signaling, especially SRE-, AP-1-, NF-kappaB-, and p53-associated pathways. Core protein activated IL-8 promoter through NF-kappaB and AP-1 and activated p21 promoter having a p53-binding site. Core protein activated the NF-kappaB pathway mainly through IKKbeta and tumor necrosis factor receptor-associated factor 2/6 and augmented p53 function by increasing both p53-DNA binding affinity and transcriptional ability itself. Direct interaction between core protein and the C-terminus of p53 was detected. In addition, the interaction between core protein and human TBP-associated factor 1128, a component of the transcriptional factor complex, was also demonstrated. Core protein may directly promote cell proliferation and induce an inflammatory reaction by activating SRE, AP-1-, and NF-kappaB-associated pathways. On the other hand, core protein could enhance p53 function. These opposing functions may result in exquisitely balancing the proliferation of hepatocytes infected with HCV.

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  • Differential expression of the L-plastin gene in human colorectal cancer progression and metastasis 査読

    M Otsuka, M Kato, T Yoshikawa, H Chen, EJ Brown, Y Masuho, M Omata, N Seki

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   289 ( 4 )   876 - 881   2001年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    To identify molecular alterations in the progression of colorectal carcinoma, we analyzed gene expression profiles of colon cancer cell lines derived from primary and metastatic tumors from a single patient. Of 2280 cDNAs investigated using our in-house microarray, the expression of 6 genes (tumor-associated antigen L6, L-plastin, the human homologue of yeast ribosomal protein S28, the B-cell translocation gene, mitochondrial aspartate-aminotransferase, and HLA-A) increased, while that of 2 genes (keratin 5 and phosphoglucomutase) decreased in metastatic-tumor-derived cells compared with primary-tumor-derived cells. Of these genes, we assessed the L-plastin gene, an actin-bundling protein, at the protein level using a tissue microarray consisting of 58 clinically stratified colorectal cancer specimens. Consistent with our microarray results, the expression of L-plastin was significantly correlated with the progression of cancer staging. Therefore, our results suggest that the L-plastin gene is a potential metastatic marker. In addition, combining cDNA microarrays and tissue arrays, as shown here, is thought to facilitate the rapid characterization of candidate biomarkers. (C) 2001 Elsevier Science.

    DOI: 10.1006/bbrc.2001.6047

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  • cDNA microarray analysis of Helicobacter pylori-mediated alteration of gene expression in gastric cancer cells 査読

    S Maeda, M Otsuka, Y Hirata, Y Mitsuno, H Yoshida, Y Shiratori, Y Masuho, M Muramatsu, N Seki, M Omata

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   284 ( 2 )   443 - 449   2001年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC  

    Helicobacter pylori infection stimulates several intracellular signaling pathways and is accompanied by increased gene expression in gastric epithelial cells. High-density cDNA microarray was used to characterize the mRNA expression profile of genes in human gastric cancer cells (MKN45, AGS) cocultured with H. pylori. Coculture with cag pathogenicity island (PAI)-positive H. pylori (wild-type) significantly upregulated mRNA expression in 8 of 2304 genes tested. In 6 (interleukin-8, I kappaB alpha, A20, ERF-1, keratin K7, glutathione peroxidase) of the 8 genes, up-regulation was confirmed by RT-PCR. In coculture with isogenic cagE-negative mutant (Delta cagE), which encodes a type TV secretion system with other genes in the cag PAI, no significant up-regulation was found. We further analyzed the role of A20. Transfection of expression vector encoding A20 resulted in an inhibition of H. pylori-mediated NF-KB activation, indicating that H, pylori-mediated A20 expression could be a negative regulator of NF-KB activation. Taken together, these results indicate the importance of microarray technology as a tool for analyzing the complex interplay between H. pylori and the host. (C) 2001 Academic Press.

    DOI: 10.1006/bbrc.2001.5006

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  • Hepatitis C virus core protein activates nuclear factor kappa B-dependent signaling through tumor necrosis factor receptor-associated factor 査読

    H Yoshida, N Kato, Y Shiratori, M Otsuka, S Maeda, J Kato, M Omata

    JOURNAL OF BIOLOGICAL CHEMISTRY   276 ( 19 )   16399 - 16405   2001年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC  

    Hepatitis C virus (HCV) core protein, a viral nucleocapsid, has been shown to affect various intracellular events including the nuclear factor kappaB (NF-kappaB) signaling supposedly associated with inflammatory response, cell proliferation, and apoptosis. In order to elucidate the effect of HCV core protein on the NF-kappaB signaling in HeLa and HepG2 cells, a reporter assay was utilized. HCV core protein significantly activated NF-kappaB signaling in a dose-dependent manner not only in HeLa and HepG2 cells transiently transfected with core protein expression plasmid, but also in HeLa cells induced to express core protein under the control of doxycycline. HCV core protein increased the DNA binding affinity of NF-kappaB in the electrophoretic mobility shift assay. Acetyl salicylic acid, an IKK beta -specific inhibitor, and dominant negative form of IKK beta significantly blocked NF-kappaB activation by HCV core protein, suggesting HCV core protein activates the NF-kappaB pathway mainly through IKK beta. Moreover, the dominant negative forms of TRAF2/6 significantly blocked activation of the pathway by HCV core protein, suggesting HCV core protein mimics proinflammatory cytokine activation of the NF-kappaB pathway through TRAF2/6. In fact, HCV core protein activated interleukin-lp promoter mainly through NF-kappaB pathway. Therefore, this function of HCV core protein may play an important role in the inflammatory reaction induced by this hepatotropic virus.

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  • Improvement of Chemosensitivity Prediction by Transcriptional Profiling in Hepatoma Cells

    Hoshida Yujin, Moriyama Masaru, Otsuka Motoyuki, Kato Naoya, Shiratori Yasushi, Seki Naohiko, Omata Masao

    Genome Informatics   12   257 - 258   2001年

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    記述言語:英語   出版者・発行元:Japanese Society for Bioinformatics  

    DOI: 10.11234/gi1990.12.257

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  • Large isoform of hepatitis delta antigen activates serum response factor-associated transcription 査読

    T Goto, N Kato, SK Ono-Nita, H Yoshida, M Otsuka, Y Shiratori, M Omata

    JOURNAL OF BIOLOGICAL CHEMISTRY   275 ( 48 )   37311 - 37316   2000年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC  

    Hepatitis delta virus infection sometimes causes severe and fulminant hepatitis as a coinfection or superinfection along with the hepatitis B virus. To elucidate the underlying mechanism of injury caused by hepatitis delta virus, we examined whether two isoforms of the hepatitis delta antigen (HDAg) had any effect on five well defined intracellular signal transduction pathways: serum response factor (SRF)-, serum response element (SRE)-, nuclear factor kappaB-, activator protein 1-, and cyclic AMP response element-dependent pathways. Reporter assays revealed that large HDAg (LIDDAg) activated the SRF- and SRE-dependent pathways. In contrast, small HDAg (LHDAg) did not activate any of five pathways. LHDAg enhanced the transcriptional ability of SRF without changing its DNA binding affinity in an electrophoretic mobility shift assay. In addition, LHDAg activated a rat SM22 alpha promoter containing SRF binding site and a human c-fos promoter containing SRE. In conclusion, LHDAg, but not SHDAg, enhances SRF-associated transcriptions. Despite structural similarities be tween the two HDAgs, there are significant differences in their effects on intracellular signal transduction pathways. These results may provide clues that will aid in the clarification of functional differences between LHDAg and SHDAg and the pathogenesis of delta hepatitis.

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  • Hepatitis C virus core protein enhances p53 function through augmentation of DNA binding affinity and transcriptional ability 査読

    Motoyuki Otsuka, Naoya Kato, Keng-Hsin Lan, Hideo Yoshida, Jun Kato, Tadashi Goto, Yasushi Shiratori, Masao Omata

    Journal of Biological Chemistry   275 ( 44 )   34122 - 34130   2000年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:American Society for Biochemistry and Molecular Biology Inc.  

    Hepatitis C virus (HCV) causes a persistent infection, chronic hepatitis, and hepatocellular carcinoma. Since there are several reports indicating that some viruses influence the tumor suppressor p53 function, we determined the effects of HCV proteins on p53 function and its mechanism determined by use of a reporter assay. Among seven HCV proteins investigated (core, NS2, NS3, NS4A, NS4B, NS5A, and NS5B), only core protein augmented the transcriptional activity of p53 and increased the expression of p21(waf1) protein, which is a major target of p53. Core protein increased both DNA-binding affinity of p53 in electrophoretic morbidity shift assay and transcriptional ability of p53 itself in a reporter assay. The direct interaction between core protein and C terminus of p53 was also shown by glutathione S-transferase fusion protein binding assay. In addition, core protein interacted with hTAF(II)28, a component of the transcriptional factor complex in vivo and in vitro. These results suggest that HCV core protein interacts with p53 and modulates p53-dependent promoter activities during HCV infection.

    DOI: 10.1074/jbc.M000578200

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  • Activation of intracellular signaling by hepatitis B and C viruses: C-viral core is the most potent signal inducer 査読

    N Kato, H Yoshida, SK Ono-Nita, J Kato, T Goto, M Otsuka, KH Lan, K Matsushima, Y Shiratori, M Omata

    HEPATOLOGY   32 ( 2 )   405 - 412   2000年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:W B SAUNDERS CO  

    To clarify the effects of hepatitis C virus (HCV) infection on hepatocytes, we analyzed and compared the induction of intracellular signals by HCV and hepatitis B virus (HBV) proteins. We examined the influence of 7 HCV (core, NS2, NS3, NS4A, NS4B, NS5A, and NS5B) and 4 HBV (precore, core, polymerase, and X) proteins on 5 well-defined intracellular signaling pathways associated with cell proliferation, differentiation, and apoptosis by use of a reporter assay. Viral protein-expression vectors were cotransfected into mammalian cells with reporter vectors having a luciferase gene driven by the following inducible cis-enhancer elements: the cyclic adenosine monophosphate response element, the serum response element (SRE), and the binding sites for nuclear factor kappa B (NF-kappa B), activator protein 1 (AP-1), and serum response factor (SRF). In addition, the activation of signals by HCV proteins was examined in a reporter plasmid having a natural interleukin-8 (IL-8) promoter upstream of a luciferase gene. Of 11 HCV and HBV proteins, HCV core had the strongest influence on intracellular signals, especially NF-kappa B-, AP-1-, and SRE-associated pathways. HCV core's activation level exceeded that of HBV X protein, a well-characterized transactivator of these signals. Moreover, HCV core activated the IL-8 promoter through NF-kappa B and AP-1. For the other proteins, HCV NS4B showed signal activation, but signals were activated at a lesser extent. The luciferase reporter assay, a recently introduced technique, helped in the elucidation of molecular events underlying the inflammatory and proliferation process in the liver induced by HCV.

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  • 超音波内視鏡下吸引細胞診(EUS-FNA)による膵腫瘍性病変の診断

    小松 裕, 多田 稔, 平田 喜裕, 大塚 基之, 笹平 直樹, 山形 道子, 戸田 信夫, 大橋 誠, 川邊 隆夫, 白鳥 康史

    超音波医学   27 ( 5 )   816 - 816   2000年5月

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    記述言語:日本語   出版者・発行元:(公社)日本超音波医学会  

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▼全件表示

書籍等出版物

  • 肝炎

    大塚 基之, 小俣 政男

    現代医療社  1998年  ( ISBN:4877430083

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    記述言語:日本語

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  • 非アルコール性脂肪肝炎を背景とした肝癌のスクリーニングの現状と問題点

    大塚 基之

    岡山医学会雑誌   135 ( 1 )   18 - 21   2023年4月

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    記述言語:日本語   出版者・発行元:岡山医学会  

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  • この症例から何を学ぶか 肝不全に至ったB型肝炎関連肝硬変の一例

    大塚 基之

    Medical Practice   39 ( 11 )   1726 - 1731   2022年11月

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    記述言語:日本語   出版者・発行元:(株)文光堂  

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  • 【膵癌研究最前線】膵癌で発現するcircular RNAとバイオマーカー応用

    清宮 崇博, 大塚 基之, 藤城 光弘

    消化器・肝臓内科   10 ( 3 )   336 - 341   2021年9月

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    記述言語:日本語   出版者・発行元:(有)科学評論社  

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  • 【ガイドライン2020から読み解くNAFLD/NASH】予後 NAFLD/NASHにおける脳・心血管イベントリスクの絞り込み 招待

    大塚 基之

    肝胆膵   83 ( 1 )   129 - 134   2021年7月

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    記述言語:日本語   出版者・発行元:(株)アークメディア  

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  • 【<最新>NAFLD/NASH 診療ガイドラインを読む】NAFLD/NASHの発癌とスクリーニング体制 招待

    大塚 基之

    臨床消化器内科   36 ( 7 )   777 - 782   2021年6月

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    記述言語:日本語   出版者・発行元:(株)日本メディカルセンター  

    <文献概要>わが国では,ウイルス肝炎を背景にもつ肝癌の割合が減少する一方,NAFLDを含む非B非C型肝癌が増加している.NAFLDを背景とした肝発癌率は,ウイルス肝炎が基礎疾患の場合よりも低率ではあるが,母集団が大きいため実数としての発癌患者数は多い.NAFLDを背景とした場合でも,ウイルス肝炎と同様,肝線維化進行例で発癌率は高くなるため,非侵襲的検査により線維化を評価し発癌リスクを層別化することで効率的にサーベイランスを行うことが重要である.一方で,発癌率は低いもののNAFLDの非硬変肝からの発癌もある.この「肝線維化が進んでいない群からの発癌」を早期に検出するための効率的なスクリーニング法は確立されておらず,時に進行した状態で見つかることもあるため,今後,非肝硬変群の中での発癌高危険群の囲い込み法の確立と効率的な肝癌スクリーニング法の確立が必須である.

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  • 【NAFLD/NASHの診断と治療-ガイドラインの改訂点と問題点】NAFLD/NASHの予後と発癌、そのスクリーニング体制の問題点 招待

    大塚 基之

    医学のあゆみ   277 ( 7 )   545 - 549   2021年5月

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    記述言語:日本語   出版者・発行元:医歯薬出版(株)  

    非アルコール性脂肪性肝疾患(NAFLD)/非アルコール性脂肪肝炎(NASH)患者では全死亡率・肝関連死亡率が一般人口に比較して増加し、そのリスクは肝線維化の進展に伴い増大する。肝臓だけでなく、とくに心血管イベント、肝臓以外のほかの臓器の癌も増えることに留意する必要がある。NAFLDを背景とした肝発癌率はウイルス肝炎を背景とした場合よりも低率ではあるが、母集団が大きいため実数としての肝癌患者数は多い。NAFLDを背景とした場合でもウイルス肝炎と同様、肝線維化進行例で発癌率は高くなるため、非侵襲的検査により線維化を評価し発癌リスクを層別化したうえで効率的にサーベイランスを行うことが重要である。一方で、発癌率は低いもののNAFLDの非硬変肝からの発癌も相当数ある。この"肝線維化が進んでいない群からの発癌"を早期に検出するための効率的なスクリーニング法は確立されておらず、ときに進行した状態で見つかることもある。そのため非肝硬変群のなかでの発癌高危険群の囲い込み法の確立と効率的な肝癌スクリーニング法の確立が今後の課題である。(著者抄録)

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    その他リンク: https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2021&ichushi_jid=J00060&link_issn=&doc_id=20210517010006&doc_link_id=issn%3D0039-2359%26volume%3D277%26issue%3D7%26spage%3D545&url=http%3A%2F%2Fwww.pieronline.jp%2Fopenurl%3Fissn%3D0039-2359%26volume%3D277%26issue%3D7%26spage%3D545&type=PierOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00005_2.gif

  • NAFLD:新ガイドラインの評価と診断、治療の最前線 NAFLD診療ガイドライン改訂のポイントと今後の課題 招待

    大塚 基之

    日本消化器病学会雑誌   118 ( 臨増総会 )   A76 - A76   2021年3月

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    記述言語:日本語   出版者・発行元:(一財)日本消化器病学会  

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  • 【B型肝炎ウイルスの感染機構と治療薬開発の最前線】新規作用機序によるB型肝炎治療薬の開発 招待

    大塚 基之

    ファルマシア   56 ( 12 )   1084 - 1088   2020年12月

  • 【NAFLD/NASHの進歩と新たな展開】発癌とそのスクリーニング体制の考え方 招待

    大塚 基之, 小池 和彦

    消化器・肝臓内科   7 ( 5 )   446 - 451   2020年5月

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  • 【B型肝炎Trends & Topics】新規抗B型肝炎ウイルス薬の開発の現状と展望 招待

    大塚 基之, 關場 一磨, 船戸 和義, 小池 和彦

    臨床消化器内科   35 ( 2 )   205 - 210   2020年1月

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    記述言語:日本語   出版者・発行元:(株)日本メディカルセンター  

    <文献概要>B型肝炎に対する核酸アナログは効果も高く安全で良い薬であるが,服薬を中断できない・HBs抗原量の低下を得にくいなどの欠点もある.そこで,核酸アナログとは異なる機序をもつ抗ウイルス薬の開発が世界中で進められている.新規抗ウイルス薬の開発には,まずウイルスライフサイクルを正確に理解し,それに応じた介入法を編み出すことが大切である.われわれは,二つの化合物,ニタゾキサニドとペボネディスタットに,cccDNAからのウイルスRNAの転写を抑制する効果があることを見出した.今後さらに,核酸アナログとは異なる新たな抗B型肝炎ウイルス薬の開発が望まれる.

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  • 【B型肝炎の新たな展開-進化を続ける基礎と臨床-】B型肝炎に対する新たな創薬研究 HBV RNAの転写を抑制する新規化合物ニタゾキサニドとペボネディスタットの同定 招待

    大塚 基之, 關場 一磨, 船戸 和義, 小池 和彦

    肝胆膵   78 ( 6 )   993 - 997   2019年6月

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  • 【炎症・免疫疾患とmicroRNA】microRNAの機能異常に着目した炎症性発癌の病態解明 招待

    大塚 基之

    臨床免疫・アレルギー科   69 ( 1 )   68 - 72   2018年1月

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  • 肝疾患における輸液処方の組み立て方 招待

    大塚 基之

    内科   120 ( 1 )   65 - 70   2017年

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:南江堂  

    DOI: 10.15106/J00974.2017288235

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  • 消化器癌の撲滅をめざして 早期診断のための囲い込みとliquid biopsyの新展開

    大塚 基之

    岡山医学会雑誌   135 ( 2 )   105 - 105   2023年8月

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  • 【ウイルス性肝炎学2023-最新の病態・診断・治療情報-】B型肝炎 臨床をめざした基礎研究 HBxタンパクの機能とウイルスの複製

    大塚 基之

    日本臨床   81 ( 増刊7 ウイルス性肝炎学2023 )   282 - 286   2023年7月

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    記述言語:日本語   出版者・発行元:(株)日本臨床社  

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  • 【肝胆膵領域におけるアルコール医学の新潮流】アルコール性肝障害の臨床研究における新知見 アルコール性肝障害における肝移植の現状

    高木 章乃夫, 竹内 康人, 八木 孝仁, 大塚 基之

    肝胆膵   86 ( 4 )   523 - 528   2023年4月

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  • Clinical application of pancreatic juice-derived small extracellular vesicles of pancreatic ductal adenocarcinoma

    Koichiro Tsutsumi, Motoyuki Otsuka

    Clinical and Translational Discovery   3 ( 2 )   2023年4月

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    Background: Recent imaging modalities have helped inthe early detection of pancreatic ductal adenocarcinoma (PDAC), resulting inimproved survival rates for patients with early-stage PDAC. However, preoperative pathological diagnosis of early-stage PDAC remains a challenge, particularly for small PDAC that is difficult to diagnose through standardendoscopic ultrasound-guided fine-needle biopsy. In this context, pancreaticjuice cytology has been re-evaluated as an important tool for the preoperativediagnosis of early-stage PDAC. Main: Pancreatic juice (PJ) comes in directcontact with PDAC lesions in the pancreatic duct and thus may contain a fewHG-PanIN/PDAC cells and specific molecules. Additionally, the PJ may containconcentrated small extracellular vesicles (sEVs) that are released from cancerlesions. sEVs are double-layered lipid-bound particles that contain cargoassociated with the cell-of-origin, including proteins, microRNA, and RNA. sEVsreleased from cancer lesions found in body fluids, such as blood, urine, andsaliva, have already been studied as potential sources of diagnostic biomarkersfor cancer. PJ-derived sEVs could serve as a “liquid biopsy” for theearly diagnosis of PDAC. However, little is known about the existence,physiological status, and function of PJ-derived sEVs and their potentialutility as biomarkers for diagnostic, surveillance, and monitoring purposes oras therapeutic targets. Conclusion: PJ-derived sEVs represent a promisingavenue for the early diagnosis of PDAC. The utility of these particles as biomarkersfor diagnostic, surveillance, and monitoring purposes, or as therapeutictargets, warrants further research. Understanding the existence, physiologicalstatus, and function of PJ-derived sEVs is crucial to unlocking their potentialas a valuable tool for overcoming PDAC.

    DOI: 10.1002/ctd2.177

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  • 【肝炎・肝硬変-知っておくべき最新の知見と実診療でのマネージメント法】肝炎・肝硬変をめぐる最近の状況 効率的な病診連携に向けて

    山内 敏正, 大塚 基之, 小木曽 智美, 糸林 詠

    Medical Practice   39 ( 11 )   1598 - 1609   2022年11月

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  • RNA結合蛋白ELAVL1のB型肝炎ウイルス複製と肝細胞癌増殖への関わり

    神崎 洋彰, 千葉 哲博, 興梠 慧輔, 日下部 裕子, 小林 和史, 叶川 直哉, 清野 宗一郎, 中村 昌人, 近藤 孝行, 齊藤 朋子, 中川 良, 小笠原 定久, 室山 良介, 中本 晋吾, 神田 達郎, 丸山 紀史, 加藤 順, 關場 一磨, 大塚 基之, 大塚 将之, 加藤 直也

    肝臓   63 ( Suppl.1 )   A335 - A335   2022年4月

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  • RNA編集酵素ADARのexosomeを介した伝播による老化に伴う肝発癌リスク増大機構の解明

    大塚 基之

    日本応用酵素協会誌   ( 55 )   20 - 21   2021年3月

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  • MicroRNAs and liver disease (SPECIAL ISSUE : Dysregulated Non-coding RNAs and Human Diseases : A Fine-Tuner Changes into a Confuser)

    Otsuka Motoyuki, Kishikawa Takahiro, Yoshikawa Takeshi, Yamagami Mari, Ohno Motoko, Takata Akemi, Shibata Chikako, Ishibashi Rei, Koike Kazuhiko

    Journal of human genetics   62 ( 1 )   75 - 80   2017年1月

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    記述言語:英語   出版者・発行元:Springer Nature  

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    その他リンク: http://search.jamas.or.jp/link/ui/2017269369

  • レジパスビル/ソホスブビル2剤併用療法の治療効果と安全性の検討

    西畠 瑞希, 南 達也, 建石 良介, 藤原 直人, 中塚 拓馬, 佐藤 雅哉, 榎奥 健一郎, 工藤 洋太郎, 中川 勇人, 浅岡 良成, 泉谷 昌志, 近藤 祐嗣, 藤永 秀剛, 田中 康雄, 大塚 基之, 加藤 直也, 四柳 宏, 池田 均, 森屋 恭爾, 小池 和彦

    肝臓   57 ( Suppl.2 )   A549 - A549   2016年9月

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  • 肝臓での慢性炎症とmicroRNA 招待

    大塚 基之

    別冊BIO Clinica 慢性炎症と疾患 2015年秋号「肝・胆・膵の慢性炎症」   4 ( 4 )   15 - 20   2015年

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  • B型肝癌における自然免疫の機能解明とその制御による発癌抑止法開発 B型肝癌感受性遺伝子MICAの発現とsheddingに関する研究

    小池和彦, 大塚基之

    B型肝癌における自然免疫の機能解明とその制御による発癌抑止法開発 平成26年度 総括・分担研究報告書   23 - 26   2015年

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  • RNA疾患―最新の病態解析から治療法展望まで―肝疾患とマイクロRNA 招待

    大塚基之

    月刊メディカル・サイエンス・ダイジェスト   40 ( 7 )   342 - 345   2014年6月

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  • HCV研究の最先端 7 HCVとmiRNA 招待

    大塚基之, 吉川剛史, 岸川孝弘, 大野元子, 高田朱弥, 柴田智華子, 小池和彦

    臨床消化器内科   29 ( 7 )   821 - 826   2014年5月

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  • 抗ウイルス補助療法としての臨床応用を見すえたフラボノイドによるmicroRNAの成熟阻害を利用したC型肝炎ウイルス増殖抑制効果について

    大塚基之, 大野元子, 小池和彦

    肝臓   55 ( Supplement 1 )   A84   2014年4月

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  • ポリフェノールによるマイクロRNA成熟抑制作用を介したインスリン抵抗性改善効果

    大野元子, 柴田智華子, 岸川孝弘, 吉川剛史, 高田朱弥, 大塚基之, 小池和彦

    消化と吸収   36 ( 2 )   234 - 237   2014年4月

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  • microRNA産生に必須なRNA分解酵素Dicerの発現量変化にともなう炎症性発癌の特徴

    大塚基之

    日本応用酵素協会誌   ( 48 )   46 - 47   2014年3月

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  • B型肝炎ウイルスの完全排除等,完治を目指した新規治療法の開発に関する包括的研究 B型肝炎ウイルス複製のmiRNAによる制御

    小池和彦, 大塚基之

    B型肝炎ウイルスの完全排除等、完治を目指した新規治療法の開発に関する包括的研究 平成25年度 総括・分担研究報告書   24 - 30   2014年

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  • 肝細胞癌とmicroRNA

    大塚基之, 小池和彦

    The Liver Cancer Journal   6 ( 3 )   2014年

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  • C型慢性肝炎からの肝癌感受性遺伝子MICAを標的とするmicroRNAの発現制御による肝癌の発症予防法と治療法の開発

    大塚基之, 高田朱弥, 吉川剛史, 岸川孝弘, 大野元子, 吉田晴彦, 小池和彦

    冲中記念成人病研究所年報   ( 39 )   51 - 52   2013年6月

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  • miR122とαフェトプロテイン

    大塚基之, 小島健太郎, 高田朱弥, 吉川剛史, 岸川孝弘, 吉田晴彦, 小池和彦

    細胞   45 ( 3 )   157 - 160   2013年3月

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    記述言語:日本語   出版者・発行元:ニューサイエンス社  

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  • 肝臓 11.肝発癌の分子機構 招待

    大塚基之, 小池和彦

    Annual Review 消化器   2013   158 - 163   2013年1月

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  • 持続炎症性発癌の病態におけるmicroRNA機能不全の関わりの解明と制御法の開発

    大塚 基之

    細胞科学研究財団助成研究報告集   24   11 - 19   2013年

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    記述言語:日本語   出版者・発行元:細胞科学研究財団  

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  • PNPLA3(I148M)遺伝子多型とC型慢性肝炎患者からの発癌リスクの検討

    佐藤雅哉, 加藤直也, 建石良介, 室山良介, 古渡礼恵, LI W, 後藤覚, 大塚基之, 椎名秀一朗, 吉田晴彦, 小俣政男, 小池和彦

    肝臓   53 ( Supplement 2 )   A715   2012年9月

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  • Stem Cell,iPS研究;再生医療,癌診療への展開 iPS関連 iPS細胞から肝細胞への分化制御

    大塚基之, 高田朱弥, 小木曽智美, 吉川剛史, 岸川孝弘, 吉田晴彦, 小俣政男, 小池和彦

    肝胆膵   65 ( 1 )   139-143   2012年7月

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  • 炎症と消化器癌 持続炎症に伴うmicroRNA機能異常を一因とした大腸発癌の病態解明

    吉川剛史, 大塚基之, 高田朱弥, 岸川孝弘, 小池和彦

    月刊消化器内科   54 ( 6 )   727-733 - 733   2012年6月

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  • IL28BマイナーアリルはC型慢性肝炎患者における低年齢発癌の危険因子である

    佐藤雅哉, 加藤直也, 建石良介, 室山良介, 古渡礼恵, LI Wenwen, 後藤覚, 大塚基之, 椎名秀一朗, 吉田晴彦, 小俣政男, 小池和彦

    肝臓   53 ( Supplement 1 )   A336   2012年4月

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  • microRNA122の機能的抑制によるIFNシグナル増強作用を介した抗ウイルス作用の増幅

    大塚基之, 高田朱弥, 小池和彦

    肝臓   53 ( Supplement 1 )   A151   2012年4月

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  • C型肝炎のすべて2012 HCVと発癌 C型肝癌のGWAS研究:MICA SNP

    加藤直也, 室山良介, 古渡礼恵, 後藤覚, 李ぶんぶん, 中川良, 大塚基之, 建石良介, 吉田晴彦, 小池和彦, 小俣政男, 中村祐輔, 松田浩一

    肝胆膵   63 ( 6 )   1045-1051   2011年12月

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  • 持続炎症に伴うmicroRNA機能異常が原因となる消化器癌の病態解明

    吉川剛史, 大塚基之, 小池和彦

    日本消化器病学会雑誌   108   A497   2011年9月

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  • 第47回日本肝臓学会総会

    大塚 基之

    The liver cancer journal : 季刊学術雑誌   3 ( 3 )   223 - 226   2011年9月

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    記述言語:日本語   出版者・発行元:メディカルレビュー社  

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  • マイクロRNAと循環器疾患 2)血管新生とマイクロRNA

    大塚基之

    血管医学   12 ( 3 )   233-240   2011年8月

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  • Genome Wide Association Studyは肝胆膵診療をいかに変えるか?肝胆膵疾患各論 GWASによるC型肝癌感受性遺伝子の同定

    加藤直也, 室山良介, 古渡礼恵, 大塚基之, 建石良介, 吉田晴彦, 小池和彦, 小俣政男, 中村祐輔, 松田浩一

    肝胆膵   62 ( 5 )   919-925   2011年5月

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  • 癌分子標的治療--歩みと今後(1)癌分子標的治療とはなにか(基本概念・開発の歴史)(2)癌分子標的治療薬の開発の歴史(歴史・分類一覧)

    大塚 基之, 小池 和彦

    リバーキャンサージャーナル   1 ( 3 )   111 - 115   2009年12月

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  • 第10回C型肝炎ウイルスおよび関連ウイルスに関する国際会議の報告--第一回東京C型肝炎ウイルス国際シンポジウムと併せて

    大塚 基之, 谷口 博順, 加藤 直也

    日本医事新報   ( 4162 )   37 - 41   2004年1月

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    記述言語:日本語   出版者・発行元:日本医事新報社  

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  • 目でみるバイオサイエンス C型肝炎ウイルスタンパクの惹起する細胞内シグナル

    加藤 直也, 大塚 基之, 吉田 英雄

    内科   92 ( 1 )   159 - 162   2003年7月

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  • ポストゲノム時代の消化器病研究の展望

    小俣 政男, 大塚 基之, 川上 高幸, 星田 有人

    日本消化器病學會雜誌 = The Japanese journal of gastro-enterology   100 ( 2 )   135 - 143   2003年2月

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    記述言語:日本語   出版者・発行元:財団法人 日本消化器病学会  

    全ヒト遺伝子配列の解明により,細胞内で産生される蛋白の数と種類が明らかにされつつある.かつては10万といわれた蛋白も3万数千と見積もられ,細胞内ネットワーク形成の登場人物も次々と明らかにされている.すなわち,細胞を1個の町に例えるとその住民は3万数千人,その人々はいわば無数の接触の営みを繰り返し行っている.その総和が細胞の表現型として現れてくる.たとえば,癌細胞はいわばその町の住民のおこした暴動とも捉えられる.一個一個の住民の動きでこの暴動の実態を明らかにする事は明白である.この網羅性による細胞内動態把握は如何に行ったら良いか,その方法につき以下に概説する.

    DOI: 10.11405/nisshoshi1964.100.135

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  • HCVと肝癌

    大塚 基之, 加藤 直也, 吉田 英雄, 吉田 晴彦, 白鳥 康史, 小俣 政男

    ウイルス   52 ( 2 )   295 - 300   2002年12月

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    記述言語:日本語   出版者・発行元:日本ウィルス学会  

    DOI: 10.2222/jsv.52.295

    CiNii Article

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  • 4. B, C型慢性肝炎における特異的発現遺伝子抽出の試み

    星田 有人, 大塚 基之, 小俣 政男

    肝臓   43 ( 10 )   471 - 472   2002年10月

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  • Inhibition of hepatoma cell growth and invasion by vitamin K2 administration in vitro.

    M Otsuka, Y Koike, N Kato, M Moriyama, T Kawakami, H Ijichi, H Taniguchi, Y Hoshida, M Omata

    HEPATOLOGY   36 ( 4 )   445A - 445A   2002年10月

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    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:W B SAUNDERS CO  

    Web of Science

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  • 実験講座 マイクロアレイの使い方 微量サンプルを用いたcDNAマイクロアレイ解析

    新井 誠人, 加藤 真樹, 大塚 基之

    ゲノム医学   2 ( 5 )   505 - 511   2002年10月

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    記述言語:日本語   出版者・発行元:メディカルレビュー社  

    CiNii Article

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  • 実験講座 マイクロアレイの使い方 肝癌細胞における抗癌剤感受性に関連する遺伝子の解析

    森山 優, 星田 有人, 大塚 基之

    ゲノム医学   2 ( 3 )   289 - 295   2002年6月

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    記述言語:日本語   出版者・発行元:メディカルレビュー社  

    CiNii Article

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  • 実験講座 マイクロアレイの使い方 肝臓疾患における遺伝子発現プロファイル

    大塚 基之, 加藤 直也, 小俣 政男

    ゲノム医学   2 ( 2 )   167 - 173   2002年4月

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    記述言語:日本語   出版者・発行元:メディカルレビュー社  

    CiNii Article

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  • Liver chip and gene shaving

    OTSUKA Motoyuki, HOSHIDA Yuujin, OMATA Masao

    日本消化器病學會雜誌 = The Japanese journal of gastro-enterology   99   A363   2002年3月

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  • テーラーメイド医療と臨床検査 遺伝子解析でのDNAチップの位置づけ in‐house cDNAマイクロアレイを用いた遺伝子発現解析

    関直彦, 吉川勉, 加藤真樹, 大塚基之

    臨床検査   46 ( 1 )   38 - 45   2002年1月

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    記述言語:日本語  

    DOI: 10.11477/mf.1542905015

    J-GLOBAL

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  • C型肝炎ウイルスコア蛋白による肝細胞死の制御とその分子機構

    大塚 基之, 加藤 直也, 小俣 政男

    肝臓   42 ( 10 )   568 - 569   2001年10月

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  • EUS-FNAが診断に有用であった食道癌の腹腔動脈周囲リンパ節転移の1例

    小松 裕, 山形 道子, 大塚 基之, 平田 喜裕, 藤島 知則, 伊佐山 浩通, 大橋 誠, 多田 稔, 吉田 晴彦, 川邊 隆夫

    超音波医学   25 ( 12 )   1150 - 1150   1998年12月

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    記述言語:日本語   出版者・発行元:(公社)日本超音波医学会  

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  • 【総胆管結石症の治療を再考する】 総胆管結石に対する内視鏡的アプローチ バルーン法を中心に

    小松 裕, 伊佐山 浩通, 大塚 基之

    胆と膵   19 ( 6 )   487 - 491   1998年6月

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    記述言語:日本語   出版者・発行元:医学図書出版(株)  

    内視鏡的乳頭バルーン拡張術(EPBD)は,文字どおり内視鏡的に十二指腸乳頭をバルーンで拡張し総胆管にアプローチする手技である.EPBDは乳頭機能を乳頭括約筋切開術(EST)に比べ温存できる可能性があり,ESTで懸念される乳頭括約筋機能廃絶による弊害を解決できる治療法による可能性がある.著者等の326例の経験では,手技に伴う出血は皆無であり,術後膵炎の頻度も従来指摘されていたほどは高くないことも明らかになってきた.一方,巨大結石例などでは結石完全除去に要す手技回数が多くなり,結石除去のみに関していえばESTよりも熟練を要すといった問題点も持っている

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  • 閉塞性黄疸: 胆と膵への内科的アプローチの新しい展開

    小俣 政男, 大塚 基之, 小松 裕, 土屋 幸浩, 山雄 健次

    日本内科学会雑誌   86 ( 4 )   652 - 665   1997年4月

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▼全件表示

産業財産権

  • がん細胞由来細胞外小胞群の単離濃縮方法、分析方法 、薬剤選択方法、キット、及び抗がん剤

    柴田智華子, 大塚基之, 藤城光弘

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    出願番号:特願PCT/JP2023/ 16313  出願日:2023年4月25日

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  • Screening For Anti-Hepatitis B Compounds

    關場一磨, 大塚基之, 小池和彦

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    出願人:ROMARK

    出願番号:特願PCT/US2019/053461  出願日:2019年9月27日

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  • 新規な全長cDNA

    磯貝 隆夫, 杉山 友康, 大槻 哲嗣, 若松 愛, 佐藤 寛之, 石井 静子, 入江 亮太郎, 吉川 勉, 大塚 基之, 仲 大地, 河合 勲二, 鈴木 克彦, 中野 浩史, 近藤 淳, 橋本 秀美, 白鳥 美和

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    出願人:バイオテクノロジー開発技術研究組合

    出願番号:特願2005-076974  出願日:2005年3月17日

    公開番号:特開2005-237384  公開日:2005年9月8日

    J-GLOBAL

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  • PKA活性調節剤

    大塚 基之, 小俣 政男

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    出願人:エーザイ株式会社

    出願番号:JP2003016386  出願日:2003年12月19日

    公開番号:WO2004-056351  公開日:2004年7月8日

    J-GLOBAL

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  • 新規な全長cDNA

    磯貝 隆夫, 杉山 友康, 大槻 哲嗣, 若松 愛, 佐藤 寛之, 石井 静子, 山本 順一, 五十野 祐子, 肥尾 弓利, 大塚 薫, 永井 啓一, 入江 亮太郎, 為近 一郎, 関 直彦, 吉川 勉, 大塚 基之, 長張 健二, 増保 安彦, 仲 大地, 河合 勲二, 鈴木 克彦, 中野 浩史, 近藤 淳, 橋本 秀美, 白鳥 美和

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    出願人:バイオテクノロジー開発技術研究組合

    出願番号:特願2003-157290  出願日:2003年3月24日

    公開番号:特開2004-008216  公開日:2004年1月15日

    J-GLOBAL

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  • 新規な全長cDNA

    磯貝 隆夫, 杉山 友康, 大槻 哲嗣, 若松 愛, 佐藤 寛之, 石井 静子, 山本 順一, 五十野 祐子, 肥尾 弓利, 齋藤 薫, 永井 啓一, 入江 亮太郎, 為近 一郎, 関 直彦, 吉川 勉, 大塚 基之, 長張 健二, 増保 安彦

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    出願人:バイオテクノロジー開発技術研究組合

    出願番号:特願2001-379298  出願日:2001年11月5日

    公開番号:特開2003-135075  公開日:2003年5月13日

    J-GLOBAL

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  • 新規な全長cDNA

    磯貝 隆夫, 杉山 友康, 大槻 哲嗣, 若松 愛, 佐藤 寛之, 石井 静子, 山本 順一, 五十野 祐子, 肥尾 弓利, 齋藤 薫, 永井 啓一, 入江 亮太郎, 為近 一郎, 関 直彦, 吉川 勉, 大塚 基之, 長張 健二, 増保 安彦

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    出願人:株式会社ヘリックス研究所, バイオテクノロジー開発技術研究組合

    出願番号:特願2001-328381  出願日:2001年9月14日

    公開番号:特開2003-088388  公開日:2003年3月25日

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受賞

  • 奨励賞(大正富山Award)

    2012年   第25回肝臓フォーラム(東部)  

    大塚 基之

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  • 第4回中外Award

    2011年   日本肝臓学会  

    大塚 基之

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  • Hepatology Research 賞

    2003年   日本肝臓学会  

    大塚 基之

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  • 消化器がんプロジェクト研究奨励賞

    2009年   中山がん研究財団  

    大塚 基之

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共同研究・競争的資金等の研究

  • RNAを中心に据えたB型肝炎の病態解明と完全排除法開発

    2023年04月 - 2026年03月

    日本医療研究開発機構(AMED)  肝炎等克服実用化研究事業 肝炎等克服緊急対策研究事業 

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  • 加齢に伴う血中細胞外小胞の性状変化による加齢疾患の発現機構の解明

    研究課題/領域番号:202310009  2023年

    三菱財団  研究助成 

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  • 膵癌における反復配列RNAの機能解析と治療選択最適化への応用

    研究課題/領域番号:22H02828  2022年04月 - 2025年03月

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    大塚 基之, 丸山 玲緒

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    配分額:17420000円 ( 直接経費:13400000円 、 間接経費:4020000円 )

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  • B型肝炎ウイルスのゲノム活性化・複製機序解明と創薬・標的因子同定に資する研究

    2022年04月 - 2025年03月

    日本医療研究開発機構(AMED)  肝炎等克服実用化研究事業 

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    担当区分:研究分担者 

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  • 慢性炎症を背景とした肝発癌の機序解明と肝癌高危険群の囲い込み法の開発

    2021年04月 - 2024年03月

    日本医療研究開発機構(AMED)  肝炎等克服実用化研究事業 

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    担当区分:研究代表者 

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  • 血中反復配列RNAの高感度検出を基盤とした新規膵癌スクリーニング法の検証

    2020年04月 - 2023年03月

    日本医療研究開発機構(AMED)  革新的がん医療実用化研究事業 

    大塚基之

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    担当区分:研究代表者 

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  • 膵癌に高発現する新しい環状RNAの同定と機能解析

    研究課題/領域番号:19H03430  2019年04月 - 2022年03月

    日本学術振興会  文部科学省 科学研究費補助金(基盤研究(B))  基盤研究(B)

    大塚基之

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    担当区分:研究代表者 

    配分額:17420000円 ( 直接経費:13400000円 、 間接経費:4020000円 )

    環状RNA(circRNA)は特定の条件下で発現するが、それらの包括的な発現状態の解析は限られていた。本研究では、環状RNAに特化したRNAシークエンシングを行い、ヒト膵腺癌(PDAC)組織で網羅的なcircRNA分析を行った。その結果、正常な膵臓組織と比較して、PDAC組織で発現が増えている40,000を超える新規の環状RNAを特定した。 その中で、12番染色体上の非コードRNA遺伝子座に由来する新規環状RNAの全長配列を決定した。circPDAC-RNAという名前をつけたこの環状RNAは、正常なヒト細胞では発現していないものの、PDACを含む癌では高発現していた。

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  • B型肝炎に関する病態生理の新たな解明に基づく制御法開発

    2019年04月 - 2022年03月

    日本医療研究開発機構(AMED)  感染症実用化研究事業(肝炎等克服実用化研究事業) 

    大塚基之

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    担当区分:研究代表者 

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  • 膵癌特異的な新規環状RNAの同定とその血中での検出による新規膵癌マーカーとしての有用性

    2019年04月 - 2021年03月

    東京大学橋渡し研究戦略的推進プログラム研究シーズA 

    大塚基之

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    担当区分:研究代表者 

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  • 細胞外微粒子の 1 粒子解析技術の開発を基 盤とした高次生命科学の新展開(代表 渡邉 力也)

    2019年 - 2025年03月

    科学技術振興機構  戦略的創造研究推進事業(CREST)「細胞外微粒子に起因する生命現象の解明とその制御に向けた基盤技術の創出」領域 

    大塚基之

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    担当区分:研究分担者 

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  • 新規樹脂チップを基材とした血中循環腫瘍細胞の捕捉・遺伝子解析システムの実用化

    2019年 - 2024年03月

    東大病院ニプロ「次世代医療技術の開発と実用化」共同研究 

    大塚基之

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    担当区分:研究代表者 

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  • 膵がん特異的リピートRNAの新規探索と応用

    2017年 - 2020年03月

    日本医療研究開発機構(AMED)  次世代がん医療創生研究事業 

    大塚基之

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    担当区分:研究代表者 

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  • B型肝炎ウイルスRNAと相互作用する宿主因子の網羅的同定とその制御による病態制御法開発

    2016年04月 - 2019年03月

    日本医療研究開発機構(AMED)  感染症実用化研究事業(肝炎等克服実用化研究事業) 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • ヘテロクロマチン由来RNAがもたらす複雑系攪乱による発癌機構解明と病態検出法開発

    研究課題/領域番号:16KT0109  2016年04月 - 2019年03月

    文部科学省  学術研究助成基金助成金 基盤研究(B)(特設分野研究)  基盤研究(B)

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

    膵癌早期からヘテロクロマチン領域から反復配列をもつRNAが発現してくることに着目し、その生物学的意義を検討した。反復配列RNAの過剰発現は、YBX1蛋白との結合を介して、DNA損傷の蓄積や染色体分裂異常を惹起し、それにより癌化のポテンシャルを上げていることが示された。さらに反復配列RNAを高感度に血中から検出することで、膵癌早期診断マーカーとして有用であることが示唆された。さらに特殊な非コードRNAとして 膵癌特異的な環状RNAを同定し全長配列を決定したうえでその組織内発現を確認し、今後の複雑系の解析次第では、新規の膵癌マーカーとして有用になる可能性が考えられた

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  • 加齢に伴うmicroRNAの機能低下と発癌ポテンシャル増大の分子機構の解明と制御

    研究課題/領域番号:16H05149  2016年04月 - 2019年03月

    文部科学省  科学研究費補助金 基盤研究(B)  基盤研究(B)

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

    加齢に伴う発癌リスクの増加の機構を解明するために、microRNAの機能変化に着目して研究をすすめた。ヒト正常線維芽細胞は細胞老化にともない炎症性サイトカインの発現が増加した。特にインターフェロン下流の応答遺伝子の発現がSTATの発現増加と核内移行によって増えてくることを見出した。この現象は、肝臓内では非実質細胞で起きていた。したがって、加齢によって細胞老化が起きると微小な慢性炎症が起き、その結果microRNAの機能が低下して発癌リスクになることが推定された。この現象はmicroRNAの機能を増強する作用をもつ化合物ROCK阻害剤で抑制できる可能性も示した。

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  • 膵臓癌の早期発見のための血清中の反復配列RNAの高感度検出法の開発

    2015年04月 - 2016年03月

    文科省橋渡し研究加速ネットワークプログラム  平成27年度研究開発委託費シーズA 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 炎症に伴うmicroRNA機能不全が惹起する炎症性発癌の病態解明と制御法の開発

    2012年10月 - 2016年03月

    科学技術振興機構(JST)  戦略的創造研究推進事業 さきがけ 「慢性炎症」領域 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • C型慢性肝炎からの肝癌発症感受性遺伝子MICAを標的とするmicroRNAの発現制御による新規の肝癌の発症予防法と治療法の開発

    2011年

    高松宮妃癌研究基金  研究助成金 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 血中循環腫瘍細胞を利用した癌の遺伝子解析技術に関する基礎検討

    研究課題/領域番号:19K07746  2019年04月 - 2023年03月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    大永 崇, 藤井 努, 大塚 基之

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    配分額:4290000円 ( 直接経費:3300000円 、 間接経費:990000円 )

    本研究では、がんゲノム医療において不可欠な患者さんから必要時に繰り返し癌遺伝子情報を取得することを低侵襲で実現するため、血中循環腫瘍細胞(CTC)をマイクロ流体デバイス;”ポリマーCTCチップ”で捕捉し、ゲルによりCTCを回収して遺伝子解析する技術の確立を目指している。今年度は、これまでに見出したゲル材料を用いて、癌細胞捕捉後のチップにゲルを充填したのちに細胞回収するテストを行い、さらに回収細胞の癌遺伝子解析を実施した。
    ゲル材料に関するテストでは、ゲルを充填したチップをホルダー等の送液装置からリリースする際にゲルの一部が欠損する場合が見られたため、その防止を目的に次の検討を行った。(1)ゲル化条件を最適化し、十分な強度のゲルを得る。(2)ホルダーリリース時の温度などの条件もゲルの強度に影響するため、その最適化を行った。
    次にチップ上のゲルに包埋された細胞を回収し、遺伝子解析を試みた。はじめに全血中に混合したMIAPaCa2(すい臓がん細胞株)をチップで捕捉したのち、そこにゲルを充填した。細胞回収では、既に見出しているゲルの溶剤を用い、細胞周辺のゲルを局所的に溶解したのちにマイクロピペットにより、エッペンドルフチューブ中にシングルセルで細胞を回収した。このようにして得た細胞サンプルについて、(1)単一の癌遺伝子のPCR適用性、(2)ddPCRによるKRAS遺伝子およびBRAF遺伝子の変異解析、を検討した。今のところPCRや遺伝子変異解析に対し、回収に関わるゲル素材などの影響は見られないが、再現性確認を含めさらに検討を重ねる。

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  • RNA機能変化を端緒とした炎症細胞社会学の確立

    研究課題/領域番号:18H05024  2018年04月 - 2020年03月

    日本学術振興会  科学研究費助成事業  新学術領域研究(研究領域提案型)

    大塚 基之

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    配分額:8060000円 ( 直接経費:6200000円 、 間接経費:1860000円 )

    消化器系の組織では、慢性炎症が惹起されると、高率にその臓器組織での腫瘍形成を見る(肝臓癌・大腸癌など)。本研究では、過去の消化器組織での持続炎症からの発癌機構の解明とそれに基づく発癌予防法の開発研究で明らかにした「慢性炎症の刺激が、細胞内の遺伝子発現の調節を司る小分子RNA(microRNA)の機能を全般的に低下させ、その結果 腫瘍が発生する」という持続炎症に続発する腫瘍の形成メカニズムについて、一細胞レベルでの検討をすすめることを目的とする。つまり、炎症の場における個々の細胞内でのmicroRNA機能を定量的に解析し、炎症の持続過程における時空間的な個々の細胞内のmicroRNAの機能の変化、およびその後の遺伝子発現の量的変化について統合的な解析を行う。さらに特に上皮の癌化に注目して、「non-coding RNA の機能から見た炎症細胞社会学とそれによる癌化機構」の概念を確立するとともに、その結果に基づく炎症と腫瘍の科学的な予防法の確立を目ざすものである。
    本年度は、これまでマウスで行われていた検討をヒト細胞・組織で検討するために、iPS細胞から腸管上皮細胞を分化誘導し、その細胞群をair-liquid interface 培養をすることで、ヒト腸管上皮組織と類似の組織上皮が培養皿内で再構成できることを見出した。しかも、腸管上皮は胚細胞や腸上皮細胞に分化しており、かつ、上皮細胞の下には線維細胞も誘導されていることから、この系は極めてヒト腸管上皮に類似した形態・細胞構成を持つことが示唆された。この系を用いて、Crohn病患者由来のiPS細胞を用いて同様の腸管上皮組織系を構築し、たとえば炎症性サイトカインの刺激に対する反応性の違い、一細胞解析による各構成細胞の細胞群のグループ分けなどを検討していく予定となっている。

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  • MICA蛋白の翻訳後修飾の分子機構解明による抗腫瘍免疫活性の増強

    研究課題/領域番号:17K09405  2017年04月 - 2020年03月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    佐藤 雅哉, 大塚 基之

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    配分額:4680000円 ( 直接経費:3600000円 、 間接経費:1080000円 )

    C型肝炎感染から肝臓癌を発生しやすい宿主因子としてMICA遺伝子の上流の一塩基多型を 以前に報告した。その際、肝癌になりやすい人はMICAの発現量が少ない(癌になっても腫瘍免疫を惹起することが出来ない)ことが推定された。しかし、MICAの発現制御は、転写レベルだけではなく、転写・翻訳語の切断による癌細胞表面からの離脱も挙げられる。本研究では、MICA蛋白の切断離脱を阻害する化合物を蛋白分解酵素阻害剤ライブラリーからFAAH阻害剤にその作用があることを同定した。FAAH阻害剤はTIMP3発現増強を介してMICA蛋白の切断を阻害した。この結果を応用すると腫瘍免疫の増強につながる可能性がある。

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  • 宿主microRNAとB型肝炎ウイルス転写産物との相互作用による病態生理の解析

    研究課題/領域番号:16K09344  2016年04月 - 2019年03月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    近藤 祐嗣, 大塚 基之

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    配分額:4810000円 ( 直接経費:3700000円 、 間接経費:1110000円 )

    HBVと宿主因子との相互作用を検討するうえで、HBV-RNAと宿主非コードRNAに着目した。配列の相同性から、HBV preS2 領域の配列と宿主let7の配列が近似することから、preS2領域のRNAが発現していると宿主のlet7の機能を減弱させることを見出した。いっぽうで、let7の過剰発現はHBVRNAに作用しcccDNAの産生を妨げる作用があることも見出した。ウイルスと宿主の相互作用がRNAを介して起こり、病態形成に関与していることが示唆された。

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  • 未来の癌予防法の確立をめざした加齢に伴う消化器癌の発生リスク増大の分子機構の解明

    2016年

    日本対がん協会  リレーフォーライフジャパン プロジェクト未来 研究助成 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 膵多段階発癌におけるmicroRNAの発現動態とその診断治療への応用

    研究課題/領域番号:15K09038  2015年04月 - 2018年03月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    山本 夏代, 伊地知 秀明, 大塚 基之

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    配分額:4810000円 ( 直接経費:3700000円 、 間接経費:1110000円 )

    正常マウスの膵組織と、膵特異的K-ras変異マウス内で誘導されるPanIN組織と、通常型浸潤性膵癌組織との三者でのmiRNA発現状況を比較した。その結果、miR-125b が正常膵組織から段階的に発現量が増えるmicroRNAとして同定できた。さらに、3次元培養では microRNA125bが核内に移行することを見いだした。microRNA125bと結合する蛋白を質量分析にて同定したところ、Galectin 3 というシャトリング蛋白が同定され、miR-125bの核移行への関与が示唆された。さらに、核内のmiR-125bは配列特異的にmRNAのスプライシングに関与していた。

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  • 肝癌感受性遺伝子MICAのshedding制御による肝発癌予防法の開発

    2015年04月 - 2016年03月

    沖中記念成人病研究所  平成27年度研究助成 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 肝癌発症予防を目的とした肝癌関連分子MICAの小分子核酸による発現制御法の開発

    研究課題/領域番号:26460984  2014年04月 - 2017年03月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    佐藤 雅哉, 大塚 基之

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    配分額:4810000円 ( 直接経費:3700000円 、 間接経費:1110000円 )

    当研究者らは、ゲノムワイドアソシエーションスタディ(GWAS)解析で、1394例のC型肝炎罹患者と5486例の非感染者のサンプルを用いてC型肝炎感染から肝臓癌を発生しやすい宿主因子としてMICA遺伝子の上流に位置するSNPを 同定し報告した(Nat Genet. 2011)。本研究ではmicroRNA25-106クラスターに由来するmicroRNAがMICA遺伝子の発現量を負に制御しうることを同定した。また、CRISPR-Cas9系を用いて Cas9に VP16の転写活性化ドメインを融合した蛋白を用いた遺伝子編集手法の応用によってMICA遺伝子座からの転写を10倍以上高めることに成功した。

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  • C型慢性肝炎からの肝癌感受性遺伝子MICAを標的としたmicroRNAの肝細胞特異的なデリバリー法の確立による新しい肝癌予防法の開発

    2014年04月 - 2015年03月

    沖中記念成人病研究所  平成26年度研究助成 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 野菜に含まれるポリフェノール類の一種アピゲニンによるmicroRNA成熟抑制作用を介した抗C型肝炎ウイルス作用

    2014年04月 - 2015年03月

    本庄国際奨学財団  「食と健康プログラム」研究助成金 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 肝癌幹細胞維持および悪性化に関わるシグナル分子の解析

    研究課題/領域番号:25290045  2013年04月 - 2016年03月

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    前田 愼, 大塚 基之, 芝田 渉

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    配分額:17030000円 ( 直接経費:13100000円 、 間接経費:3930000円 )

    我が国では肝癌によって毎年約3.5万人が死亡しており、難治進行癌に対する治療法はいまだ確立せずに予後は悪い。癌部の多くの割合を占める分化した癌細胞に対する治療では十分ではなく、治療抵抗性や転移、再発の原因として幹細胞の特異的な形質を理解する必要がある。本研究では新たな肝臓癌マウスモデルの作成、肝癌幹細胞培養による細胞株の樹立、癌幹細胞変化のメカニズムとしての上皮ー間葉転換の解析を行い、肝癌幹細胞をターゲットとする治療開発へ向けた基盤を構築した。

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  • 肝特異的microRNAの発現低下に伴う細胞内代謝物量変化とその肝癌治療への応用

    研究課題/領域番号:25460979  2013年04月 - 2016年03月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    近藤 祐嗣, 大塚 基之, 吉田 晴彦

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    配分額:5070000円 ( 直接経費:3900000円 、 間接経費:1170000円 )

    進行肝癌における有効な治療法が不十分である中、本研究では、肝癌におけるmiRNA122の低下に着目し検討した。その結果、miRNA122の発現が低下した肝組織ではアルギニンの量が増えていた。アルギニンは、miRNA122の標的因子であるCAT-1の発現量が増えることにより、取り込まれる量が増えていた。アルギニンは一酸化窒素(NO)合成酵素の基質であるが、実際 miR122低下肝癌では細胞内NOの量が増えており、それに伴って癌幹細胞マーカーの発現が増加した。これらから、miRNA122発現の低下した肝癌においては、アルギニン摂取の制限が癌幹細胞的な形質を減弱させる補助療法となることが示唆された。

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  • microRNA122の発現低下に伴うアミノ酸代謝系の変化を介した肝臓癌の癌幹細胞の形質獲得機構の解析とそれに基づく制御法の開発

    2013年04月 - 2014年03月

    日本消化器病学会  研究助成 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • MICAの発現調節による肝炎からの肝発癌予防法の開発

    2013年04月 - 2014年03月

    Liver Forum in Kyoto 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 非コード反復配列RNAの発現を主因とした多段階発癌の発癌機構の解明と制御

    研究課題/領域番号:25293076  2013年 - 2015年

    文部科学省  科学研究費補助金(基盤研究(B))  基盤研究(B)

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

    配分額:6500000円 ( 直接経費:5000000円 、 間接経費:1500000円 )

    癌は癌遺伝子・癌抑制遺伝子の変異に伴う多段階発癌が主要な発癌経路であると推定されているが、なぜそれらの遺伝子変異が最終的に雑多な遺伝子異常を伴う細胞癌化に結びつくのかはいまだ明確になっていない。本申請では、多段階発癌の初期の遺伝子異常の段階から非コード反復配列RNAが発現し、DNA修復因子であるYB-1蛋白と結合し細胞質に局在させることを明らかにした。この反復配列がゲノムDNAやミトコンドリアDNAの変異修復を阻害することで、細胞内環境を攪乱しDNA損傷を惹起することをつきとめた。反復配列RNAのYB1への結合を阻害するなどの介入法によって発癌を抑制できる可能性が示唆された。

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  • 膵癌モデルマウスを用いた非機能性反復配列RNAの膵発癌における生物学的意義の検討

    研究課題/領域番号:24591005  2012年04月 - 2015年03月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    山本 夏代, 大塚 基之, 伊地知 秀明

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    配分額:5330000円 ( 直接経費:4100000円 、 間接経費:1230000円 )

    膵癌で早期に発現する非コードRNAの一種、反復配列RNAの発現状況を検討したところ、膵癌組織特異的で正常組織では全く発現が見られなかった。そのためこの反復配列RNAが癌の表現型に何か寄与しているのではないかと考え、細胞で発現する状況を創ってみたところ、遺伝子異常の修復障害や染色体の分裂異常が惹起された。その分子機構はまだ解明すべき点があるが、この非コードRNAの発現が癌の悪性化に寄与していると考えられた。

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  • 非コードRNAによるIFN作用増強効果の機構解析とC型肝炎ウイルス治療への応用

    研究課題/領域番号:24590956  2012年04月 - 2015年03月

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    吉田 晴彦, 大塚 基之

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    配分額:5460000円 ( 直接経費:4200000円 、 間接経費:1260000円 )

    IFNの作用を増強するmicroRNAをスクリーニングしたところ、miR122が同定された。miR122はインターフェロンシグナルを負に制御するSOCS3のプロモーターのメチル化を促進することが示された。従ってIFNの投与によりmiR122の発現が低下するとSOCS3の発現も増強しnegative feedbackになることが示唆された。miR122の発現を減らすアピゲニンはHCVの複製をIFNと併用することで効率的に抑えることが示された。

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  • コーヒーの持つmicroRNA機能の増強作用を介した脂肪肝と肝発癌の予防効果の検討

    2012年

    全日本コーヒー協会  研究助成 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • microRNA産生に必須なRNA分解酵素Dicerの機能撹乱が原因となる炎症性発癌機構の解明

    2012年

    日本応用酵素協会  酵素研究助成金 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • RNP構成因子DDX20によるB型肝炎関連肝癌の抑制機構の解析

    研究課題/領域番号:23590960  2011年 - 2013年

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    五藤 忠, 大塚 基之, 吉田 晴彦

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    配分額:5200000円 ( 直接経費:4000000円 、 間接経費:1200000円 )

    肝発癌の一因として網羅的解析で同定されたDDX20の発現低下によって惹起される分子変化を検討した。その結果、DDX20はmicroRNAの成熟に必須の因子であるRISCの構成因子であり、発現が減ると特定のmicroRNAの成熟が阻害されることが判明した。特にmicroRNA140-5pの発現低下は発癌に密接に関わるNF-KBの活性化に関与することを見いだしたが、それは、microRNA140の発現低下によってDnmt1の発現が増え、メタロチオネインを減らすためと考えられた。これらの現象はmicroRNA140のノックアウトマウスでも確認された。今後これらの結果を応用した肝癌予防策が期待される。

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  • 上皮細胞と樹状細胞による腸管免疫と宿主恒常性の制御機構の解明

    研究課題/領域番号:23590933  2011年 - 2013年

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    平田 喜裕, 大塚 基之, 山田 篤生

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    配分額:5200000円 ( 直接経費:4000000円 、 間接経費:1200000円 )

    腸管の恒常性制御機構の解明のため、腸管上皮細胞と樹状細胞の役割を検討した。上皮特異的IKKノックアウトは、Citrobacter感染腸炎の減弱を認めなかった。一方血球細胞ではIKKシグナルが樹状細胞と病原体の制御に重要であった。上皮細胞の細胞間接着分子は腸管内細菌の制御と腸炎の抑制作用があると考えられた。一方樹状細胞ではTGFbシグナルが、大腸、胃など消化管の抗炎症作用に必須であった。樹状細胞のTGFbR2のヘテロノックアウトマウスではCitrobacter腸炎の悪化がみられた。樹状細胞のTGFbシグナルは腸内細菌を感知、制御し個体の恒常性維持に寄与することが明らかになった。

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  • 膵癌における非機能性反復配列RNAが惹起する癌と間質相互作用の解析

    2011年

    佐川がん研究振興財団  研究助成金 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • C型慢性肝炎からの肝癌感受性遺伝子MICAを標的とするmicroRNAの発現制御による肝癌の発症予防法と治療法の開発

    2011年

    沖中記念成人病研究所  研究助成 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 非機能性反復配列RNAが惹起する癌と間質相互作用

    2011年

    アステラス病態代謝研究会  研究助成金 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 難治消化器がんの発生・進展におけるNF-kappaBシグナルの関与

    研究課題/領域番号:22300317  2010年 - 2012年

    文部科学省  科学研究費補助金(基盤研究(B))  基盤研究(B)

    前田 愼, 大塚 基之, 伊地知 秀明

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    担当区分:連携研究者  資金種別:競争的資金

    配分額:17160000円 ( 直接経費:13200000円 、 間接経費:3960000円 )

    1)難治がんモデルの作成とNF-kappaB活性化との関連の検討膵臓がん:膵特異的oncogenic K-ras発現と膵特異的TGFβレセプターIIノックアウトによってヒトの膵臓癌に病理学的に近い癌が観察されるが(Ijichi H et al.Genes Dev 2005)、このマウスにIKKβ floxedおよびIKKαAAマウスを交配することにより、その影響を検討した結果、腫瘍発生は抑制された。スキルス胃がん:Her2(ErbB2)トランスジェニックマウスの作成を行ったが、これまでのところ(4ヶ月目まで)異常は見られていない。現在長期経過観察中である。さらにHelicobacterモデルを行っている。2)恒常的IKKβ活性化マウスの作成恒常的IKKβ活性化が発癌に及ぼす影響を検討するため、恒常活性型IKKβ(IKKβEE(S177E,S181E))を胃、腸で強く発現するCK-19プロモーター下に発現させた。7か月目までは大きな異常は見られなかった。大腸炎症発癌モデルであるAOM+DSSモデルを用いて、検討を行い、やや炎症が増悪する傾向が得られた。現在詳細を解析中である。3)プロテアソーム阻害剤を用いた胃癌治療への可能性の検討胃癌ではIn vitroおよびIn vivoにおいて明らかにその抗腫瘍効果を認めた。その原因として増殖抑制およびアポトーシス亢進によるものであることが...

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  • 肝特異microRNAの機能解析とその発現制御による効率的肝細胞分化誘導法の開発

    研究課題/領域番号:22590718  2010年 - 2012年

    文部科学省  科学研究費補助金(基盤研究(C))  基盤研究(C)

    近藤 祐嗣, 大塚 基之, 吉田 晴彦

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    担当区分:連携研究者  資金種別:競争的資金

    配分額:4420000円 ( 直接経費:3400000円 、 間接経費:1020000円 )

    肝細胞内の全microRNAの80%以上を占めているmiR122は肝細胞特異的に発現するmicroRNAであり、かつ肝癌でその発現が落ちているなどの背景から、肝細胞を正常な肝細胞として維持する機能を有している可能性が考えられる。本年度はmiR122の肝細胞分化に与える生理機能をin vitroでのmiR122過剰発現系・ノックダウン系とmiR122の機能的ノックアウトマウスによりin vivoで解明することを目的とした。miR122に対するanti-sense配列RNAをH1 promoter下に発現するレンチウイルスを作製しこれを肝細胞株に感染させmiR122の機能をノックダウンしたstable cell lineを樹立した。miR122の機能についてはluciferase遺伝子の下流5'UTRにmiR122の標的配列を組み込んだレポーターコンストラクトを作製しtransfectionすることでluciferaseの発光を定量することにより確認した。反対に過剰発現系については、miR122のprecursorをCMV promoter下に発現するコンストラクトを作製しレンチウイルスに組み込んで発現した。miR122のanti-senseを発現するコンストラクトを切り出し、マウスゲノムに組み込んでtransgenic mouseを作製する。これにより機能的にmiR122をノッ...

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  • 持続炎症に併発するmiRNA機能減弱が原因となる消化器癌の発癌機構と制御法の探索

    研究課題/領域番号:22390058  2010年 - 2012年

    文部科学省  科学研究費補助金(基盤研究(B), 基盤研究(B))  基盤研究(B), 基盤研究(B)

    大塚 基之, 立石 敬介, 前田 愼

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    担当区分:研究代表者  資金種別:競争的資金

    配分額:18590000円 ( 直接経費:14300000円 、 間接経費:4290000円 )

    「炎症性ストレスによる慢性的な『miRNA機能阻害』によって引き起こされる炎症性発癌」という新規の疾患概念を検証するために、昨年度に樹立したmiRNA反応性GFPマウスを用いて、炎症性発癌モデルにおけるmiRNAの機能変化を検定した。CMVプロモーターで転写される蛍光蛋白であるGFP遺伝子の3'UTRにmiRNA122/let7b/miR29bの標的配列を組み込んだコンストラクトを恒常的に発現するトランスジェニックマウスで、AOM/DSSを用いた大腸の炎症性発癌モデルの過程でのGFPの発現強度を免疫組織染色で検討したところ、持続炎症によってGFPの発現は増強し、慢性炎症に伴ってmicroRNAの機能が減弱することが示唆された。今年度は介入試験を行なうため、薬剤ライブラリーとレポーター細胞を用いてmicroRNAの機能を増強する薬剤を探索した。300種以上の化合物からある種のkinaseがmicroRNA機能を増強することをみいだし、その機構を解析した。その結果、この薬剤はPAIP2と呼ばれるpoly Abinding proteinに相互作用する分子の発現を増やしてその機能を抑制し、microRNAによるpolyAの短縮を増強する作用があることをみいだした。この薬剤を先のAOM/DSSによる炎症性発癌モデルでin vivo投与したところ、確かに腫瘍形成が抑制された。Dicer遺伝子ノックアウトマウスではその効果は見られなかったことから、その作用はmicroRNAの機能を介していることが示唆された。今後さらにその分子機構を解析するのと並行して、他の炎症発癌モデルを用いて炎症性発癌におけるその薬効の普遍性を検証する予定である。

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  • p38コンディショナルノックアウトマウスを用いた消化器領域の炎症性疾患(感染性・炎症性腸疾患)についての病態解析

    2010年

    三共生命科学研究振興財団  海外共同研究支援助成 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 持続炎症性発癌の病態におけるmicroRNA機能不全の関わりの解明と制御法の開発

    2010年

    細胞科学研究財団  研究助成 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • インターフェロン作用増強を介する microRNAを用いた慢性C型肝炎に対する核酸療法開発のための分子機構の解明

    2010年

    持田記念医学薬学振興財団  研究助成金 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • トランスジェニックマウスとメタボロミクスによる肝特異的microRNA122の機能解析

    2010年

    荒木記念医学・生化学研究振興基金  研究助成金 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 腸管内病原性細菌に対する腸管上皮細胞から免疫担当細胞への免疫応答連携におけるp38 MAPKの組織特異的機能の解析

    2010年

    ヤクルト・バイオサイエンス振興財団  研究助成 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • iPS細胞からのヒト肝炎ウイルス複製マウスモデルの作製と応用

    研究課題/領域番号:21890052  2009年 - 2010年

    文部科学省  科学研究費補助金(若手研究(スタートアップ), 研究活動スタート支援)  若手研究(スタートアップ), 研究活動スタート支援

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

    配分額:2652000円 ( 直接経費:2040000円 、 間接経費:612000円 )

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  • 生体ストレスが惹起するmiRNA機能異常に関わる分子機構の同定

    2009年

    武田科学振興財団  医学系研究奨励 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 持続炎症に伴う発癌の原因としての炎症性サイトカインが惹起するmicroRNA機能異常の解析

    2009年

    病態代謝研究会  研究助成金 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 持続炎症に伴うmicroRNA機能不全が惹起する肝発癌機構解明とその発癌機構への新規介入法の開発

    2009年

    がん研究振興財団  研究助成金 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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  • 消化器発癌の原因としての慢性持続炎症に伴うmicroRNA機能不全の機構解明と治療介入法の開発

    2009年

    千里ライフサイエンス振興財団  研究助成金 

    大塚 基之

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    担当区分:研究代表者  資金種別:競争的資金

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その他研究活動

  • Editorial Board

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    1) Academic Editor: PLoS ONE (2013.6.~ ),
    2) Editorial Board: World Journal of Gastroenterology (2014.1.~ )
    3) Editorial Board: Scientific Reports (2015.3.~ )
    4) Editorial Board: Hepatology International (2015.4.~ )
    5) Editorial Board: Experimental and Therapeutic Medicine (2020.4.~ )
    6) Editorial Board: Oncology Letters (2020.6.~ )

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担当授業科目

  • 内科学 (2023年度) 1・2学期  - [第1学期]月4,月5,水6, [第2学期]月4,月5,金6

  • 消化器・肝臓内科学実習 (2023年度) 特別  - その他

  • 消化器・肝臓内科学演習 (2023年度) 特別  - その他

  • 消化器・肝臓内科学I(演習・実習) (2023年度) 特別  - その他

  • 消化器・肝臓内科学I(講義・演習) (2023年度) 特別  - その他

  • 消化器・肝臓内科学II(演習・実習) (2023年度) 特別  - その他

  • 消化器・肝臓内科学II(講義・演習) (2023年度) 特別  - その他

  • 消化器系(臓器・系別統合講義) (2023年度) 特別  - その他

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