Faculty Profiles - OKAMOTO Kuniaki

Papers - OKAMOTO Kuniaki

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Novel mechanism of cisplatin resistance in head and neck squamous cell carcinoma involving extracellular vesicles and a copper transporter system. Reviewed International journal

Tatsuo Ogawa, Kisho Ono, Shoji Ryumon, Hotaka Kawai, Tomoya Nakamura, Koki Umemori, Kunihiro Yoshida, Hideka Kanemoto, Kyoichi Obata, Norie Yoshioka, Tatsuo Okui, Kuniaki Okamoto, Hitoshi Nagatsuka, Soichiro Ibaragi

Head & neck 2024.1

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Cisplatin (CDDP) plays a central role in chemotherapy for head and neck squamous cell carcinoma (HNSCC), but drug resistance in HNSCC chemotherapy remains a problem, and the mechanism of CDDP resistance is unclear. We investigated CDDP-resistance mechanisms mediated by extracellular vesicles (EVs) and ATPase copper transporting beta (ATP7B) in HNSCC. METHODS: We established CDDP-resistant sublines of HNSCC cells and verified their ATP7B expression. We used an EV secretion inhibitor (GW4869) and ATP7B short hairpin (sh)RNA transfection to examine the correlation between EV secretion and ATP7B expression. RESULTS: The CDDP-resistant HNSCC sublines showed decreased CDDP sensitivity and increased ATP7B expression. GW4869 suppressed ATP7B expression, and ATP7B shRNA transfection suppressed EV secretion. The suppressions of EV secretion and ATP7B expression both enhanced CDDP's cell-killing effect. CONCLUSIONS: EVs were involved in the ATP7B-mediated mechanism underlying CDDP resistance. Further clarification of the EV-induced CDDP-resistance mechanism may lead to novel therapeutic strategies for HNSCC.

DOI： 10.1002/hed.27620

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Rab11 suppresses head and neck carcinoma by regulating EGFR and EpCAM exosome secretion. Reviewed International journal

Kunihiro Yoshida, Kaung Htike, Takanori Eguchi, Hotaka Kawai, Htoo Shwe Eain, Manh Tien Tran, Chiharu Sogawa, Koki Umemori, Tatsuo Ogawa, Hideka Kanemoto, Kisho Ono, Hitoshi Nagatsuka, Akira Sasaki, Soichiro Ibaragi, Kuniaki Okamoto

Journal of oral biosciences 2023.12

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

OBJECTIVES: Rab11(Rab11a and Rab11b) localizes primarily along recycling endosomes in cells and is involved in various intracellular trafficking processes, including membrane receptor recycling and secretion of exosomes or small extracellular vesicles (EVs). Although Rab11 is closely associated with the progression and metastasis of various cancer types, little is known about Rab11' role in head and neck squamous cell carcinoma (HNSCC). In this study, we investigated the roles of Rab11a and Rab11b in HNSCC. METHODS: The clinical significance of Rab11 expression in HNSCC was investigated using a public database and tissue microarray analysis. Stable cell lines with loss and gain of Rab11a or Rab11b were originally established to investigate their roles in the proliferative, migratory, and invasive capabilities of HNSCC cells. RESULTS: Database analysis revealed a significant association between Rab11b mRNA expression and a favorable patient survival rate in HNSCC. Tissue microarray analysis revealed that Rab11b expression was the highest in normal tissues and gradually decreased across the stages of HNSCC progression. Overexpression of Rab11a or Rab11b resulted in a decrease in epidermal growth factor receptor (EGFR), Epithelial cell adhesion molecule (EpCAM) exosome secretion, and the migratory and invasive potential of HNSCC cells. The knockdown of Rab11a or Rab11b increased EpCAM/CD9 exosome secretion in addition to the migratory and invasive potential of HNSCC cells. CONCLUSIONS: Rab11 suppresses HNSCC by regulating EGFR recycling and EpCAM exosome secretion in HNSCC cells. Our results indicate that Rab11b is a superior prognostic indicator of HNSCC and holds promise for developing novel therapeutic strategies.

DOI： 10.1016/j.job.2023.11.007

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Abr, a Rho-regulating protein, modulates osteoclastogenesis by enhancing lamellipodia formation by interacting with poly(ADP-ribose) glycohydrolase. Reviewed International journal

Fatima Farhana, Eiko Sakai, Yu Koyanagi, Yu Yamaguchi, Mohammad Ibtehaz Alam, Kuniaki Okamoto, Takayuki Tsukuba

Molecular biology reports 2023.7

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Osteoclasts are multinucleated bone-resorbing cells formed by the fusion of monocyte/macrophage lineage. During osteoclast differentiation, Rho GTPases are involved in various processes, including cell migration, adhesion, and polarity. However, the role of Rho-regulatory molecules in the regulation of osteoclast differentiation remains unclear. In this study, among these genes, we focused on active breakpoint cluster region-related (Abr) protein that is a multifunctional regulator of Rho GTPases. METHODS AND RESULTS: We examined using knockdown and overexpression experiments in RANKL-stimulated RAW-D macrophages whether Abr regulates osteoclast differentiation and cell morphology. We observed an increase in Abr expression during osteoclast differentiation and identified expression of a variant of the Abr gene in osteoclasts. Knockdown of Abr suppressed osteoclast differentiation and resorption. Abr knockdown markedly inhibited the expression of osteoclast markers, such as Nfatc1, c-fos, Src, and Ctsk in osteoclasts. Conversely, overexpression of Abr enhanced the formation of multinucleated osteoclasts, bone resorption activity, and osteoclast marker gene expression. Moreover, Abr overexpression accelerated lamellipodia formation and induced the formation of well-developed actin in osteoclasts. Importantly, the Abr protein interacted with poly(ADP-ribose) glycohydrolase (PARG) and Rho GTPases, including RhoA, Rac1/2/3, and Cdc42 in osteoclasts. CONCLUSIONS: Taken together, these results indicate that Abr modulates osteoclastogenesis by enhancing lamellipodia formation via its interaction with PARG.

DOI： 10.1007/s11033-023-08690-0

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Rab44 Deficiency Induces Impaired Immune Responses to Nickel Allergy. Reviewed International journal

Mayuko Noguromi, Yu Yamaguchi, Keiko Sato, Shun Oyakawa, Kuniaki Okamoto, Hiroshi Murata, Takayuki Tsukuba, Tomoko Kadowaki

International journal of molecular sciences 24 ( 2 ) 2023.1

Language：English Publishing type：Research paper (scientific journal)

Rab44 was recently identified as an atypical Rab GTPase that possesses EF-hand and coiled-coil domains at the N-terminus, and a Rab-GTPase domain at the C-terminus. Rab44 is highly expressed in immune-related cells such as mast cells, macrophages, osteoclasts, and granulocyte-lineage cells in the bone marrow. Therefore, it is speculated that Rab44 is involved in the inflammation and differentiation of immune cells. However, little is known about the role of Rab44 in inflammation. In this study, we showed that Rab44 was upregulated during the early phase of differentiation of M1- and M2-type macrophages. Rab44-deficient mice exhibited impaired tumor necrosis factor alpha and interleukin-10 production after lipopolysaccharide (LPS) stimulation. The number of granulocytes in Rab44-deficient mice was lower, but the lymphocyte count in Rab44-deficient mice was significantly higher than that in wild-type mice after LPS stimulation. Moreover, Rab44-deficient macrophages showed impaired nickel-induced toxicity, and Rab44-deficient mice showed impaired nickel-induced hypersensitivity. Upon nickel hypersensitivity induction, Rab44-deficient mice showed different frequencies of immune cells in the blood and ears. Thus, it is likely that Rab44 is implicated in immune cell differentiation and inflammation, and Rab44 deficiency induces impaired immune responses to nickel allergies.

DOI： 10.3390/ijms24020994

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HSP90 drives the Rab11a‐mediated vesicular transport of the cell surface receptors in osteoclasts Reviewed International journal

Manh Tien Tran, Yuka Okusha, Kaung Htike, Chiharu Sogawa, Takanori Eguchi, Tomoko Kadowaki, Eiko Sakai, Takayuki Tsukuba, Kuniaki Okamoto

Cell Biochemistry and Function 40 ( 8 ) 838 - 855 2022.12

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley

Rab11a, which ubiquitously localizes to early and recycling endosomes, is required for regulating the vesicular transport of cellular cargos. Interestingly, our previous study revealed that Rab11a served as a negative regulator of osteoclastogenesis by facilitating the lysosomal proteolysis of (1) colony-stimulating factor-1 (c-fms) receptor and (2) receptor activator of nuclear factor-κB (RANK) receptor, thereby resulting in inhibition of osteoclast (OC) differentiation, maturation, and bone-resorbing activity. However, the molecular mechanisms of how Rab11a negatively affected osteoclastogenesis were largely unknown. Heat shock protein (HSP90), including two isoforms HSP90α and HSP90β, necessitates the stability, maturation, and activity of a broad range of its clients, and is essentially required for a vast array of signal transduction pathways in nonstressful conditions. Furthermore, cumulative evidence suggests that HSP90 is a vital element of the vesicular transport network. Indeed, our recent study revealed that HSP90, a novel effector protein of Rab11b, modulated Rab11b-mediated osteoclastogenesis. In this study, we also found that Rab11a interacted with both HSP90α and HSP90β in OCs. Upon blockade of HSP90 ATPase activity by a specific inhibitor(17-allylamino-demethoxygeldanamycin), we showed that (1) the ATPase domain of HSP90 was a prerequisite for the interaction between HSP90 and Rab11a, and (2) the interaction of HSP90 to Rab11a sufficiently maintained the inhibitory effects of Rab11a on osteoclastogenesis. Altogether, our findings undoubtedly indicate a novel role of HSP90 in regulating Rab11a-mediated osteoclastogenesis.

DOI： 10.1002/cbf.3745

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/cbf.3745

Coronin 1CはGDP特異的Rab44エフェクターでありマクロファージの細胞運動を調節することで破骨細胞形成を制御する

山口優, 門脇知子, 相原希美, 大山要, 岡元邦彰, 坂井詠子, 筑波隆幸

日本生化学会大会プログラム・講演要旨集 95回 1P - 175 2022.11

HSP90 drives the Rab11a-Mediated Vesicular Transport of the Cell Surface Receptors in Osteoclasts Reviewed International coauthorship

Tran MT, Okusha Y, Htike K, Sogawa C, Eguchi E, Kadowaki T, Sakai E, Tsukuba T, Okamoto K.

Cell Biochem Funct 40 ( 8 ) 828 - 855 2022.9

高転移性癌細胞由来の細胞外小胞に搭載されたMMP3によるCtgf/Ccn2発現調節機能と癌転移促進(Extracellular vesicles enriched with moonlighting metalloproteinase are highly transmissive, Pro-tumorigenic, and trans-activates cellular communication network factor(CCN2/CTGF): CRISPR against cancer)

奥舎有加, 江口傑徳, Tran Manh T., 十川千春, 吉田賀弥, 板垣まみ, Taha Eman A., 小野喜章, 青山絵理子, 岡村裕彦, 小崎健一, Calderwood Stuart K., 滝川正春, 岡元邦彰

Journal of Oral Biosciences Supplement 2022 35 - 35 2022.9

細胞外小胞に搭載されたムーンライティングMMPによるマトリックス制御と転移促進(Metalloproteinase on extracellular vesicles regulates ECM in tumor microenvironment and promotes invasion and metastasis)

奥舎有加, タハ・エマン, 陸彦因, シータ・モナ, 河合穂高, 十川千春, 岡元邦彰, 江口傑徳

日本癌学会総会記事 81回 P - 1118 2022.9

Coronin1C Is a GDP-Specific Rab44 Effector That Controls Osteoclast Formation by Regulating Cell Motility in Macrophages. Reviewed International journal

Yu Yamaguchi, Tomoko Kadowaki, Nozomi Aibara, Kaname Ohyama, Kuniaki Okamoto, Eiko Sakai, Takayuki Tsukuba

International journal of molecular sciences 23 ( 12 ) 2022.6

Language：English Publishing type：Research paper (scientific journal)

Osteoclasts are multinucleated bone-resorbing cells that are formed by the fusion of macrophages. Recently, we identified Rab44, a large Rab GTPase, as an upregulated gene during osteoclast differentiation that negatively regulates osteoclast differentiation. However, the molecular mechanisms by which Rab44 negatively regulates osteoclast differentiation remain unknown. Here, we found that the GDP form of Rab44 interacted with the actin-binding protein, Coronin1C, in murine macrophages. Immunoprecipitation experiments revealed that the interaction of Rab44 and Coronin1C occurred in wild-type and a dominant-negative (DN) mutant of Rab44, but not in a constitutively active (CA) mutant of Rab44. Consistent with these findings, the expression of the CA mutant inhibited osteoclast differentiation, whereas that of the DN mutant enhanced this differentiation. Using a phase-contrast microscope, Coronin1C-knockdown osteoclasts apparently impaired multinuclear formation. Moreover, Coronin1C knockdown impaired the migration and chemotaxis of RAW-D macrophages. An in vivo experimental system demonstrated that Coronin1C knockdown suppresses osteoclastogenesis. Therefore, the decreased cell formation and fusion of Coronin1C-depleted osteoclasts might be due to the decreased migration of Coronin1C-knockdown macrophages. These results indicate that Coronin1C is a GDP-specific Rab44 effector that controls osteoclast formation by regulating cell motility in macrophages.

DOI： 10.3390/ijms23126619

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Rab34 plays a critical role as a bidirectional regulator of osteoclastogenesis Reviewed

Yunxia Feng, Manh Tien Tran, Yanyin Lu, Kaung Htike, Yuka Okusha, Chiharu Sogawa, Takanori Eguchi, Tomoko Kadowaki, Eiko Sakai, Takayuki Tsukuba, Kuniaki Okamoto

Cell Biochemistry and Function 2022.3

口腔癌のエクソソームを介した腫瘍進展機序の解明と新規治療戦略の開発に向けて分子シャペロン搭載エクソソームの可能性

小野喜章, 江口傑徳, 十川千春, 奥舎有加, 岡元邦彰, 佐々木朗

口腔組織培養学会誌 31 ( 1 ) 33 - 34 2022.3

Resident stroma-secreted chemokine CCL2 governs myeloid-derived suppressor cells in the tumor microenvironment Reviewed

May Wathone Oo, Hotaka Kawai, Kiyofumi Takabatake, Shuta Tomida, Takanori Eguchi, Kisho Ono, Qiusheng Shan, Toshiaki Ohara, Saori Yoshida, Haruka Omori, Shintaro Sukegawa, Keisuke Nakano, Kuniaki Okamoto, Akira Sasaki, Hitoshi Nagatsuka

JCI Insight 2021.12

A novel role of HSP90 in regulating osteoclastogenesis by abrogating Rab11b-driven transport Reviewed

Manh Tien Tran, Yuka Okusha, Yunxia Feng, Chiharu Sogawa, Takanori Eguchi, Tomoko Kadowaki, Eiko Sakai, Takayuki Tsukuba, Kuniaki Okamoto

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 1868 ( 10 ) 119096 - 119096 2021.9

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier BV

Heat shock protein 90 (HSP90) is a highly conserved molecular chaperone that plays a pivotal role in folding, activating and assembling a variety of client proteins. In addition, HSP90 has recently emerged as a crucial regulator of vesicular transport of cellular proteins. In our previous study, we revealed Rab11b negatively regulated osteoclastogenesis by promoting the lysosomal proteolysis of c-fms and RANK surface receptors via the axis of early endosome-late endosome-lysosomes. In this study, using an in vitro model of osteoclasts differentiated from murine macrophage-like RAW-D cells, we revealed that Rab11b interacted with both HSP90 isoforms, HSP90 alpha (HSP90α) and HSP90 beta (HSP90β), suggesting that Rab11b is an HSP90 client. Using at specific blocker for HSP90 ATPase activity, 17-allylamino-demethoxygeldanamycin (17-AAG), we found that the HSP90 ATPase domain is indispensable for maintaining the interaction between HSP90 and Rab11b in osteoclasts. Nonetheless, its ATPase activity is not required for regulating the turnover of endogenous Rab11b. Interestingly, blocking the interaction between HSP90 and Rab11b by either HSP90-targeting small interfering RNA (siHSP90) or 17-AAG abrogated the inhibitory effects of Rab11b on osteoclastogenesis by suppressing the Rab11b-mediated transport of c-fms and RANK surface receptors to lysosomes via the axis of early endosome-late endosome-lysosomes, alleviating the Rab11b-mediated proteolysis of these surface receptors in osteoclasts. Based on our observations, we propose a HSP90/Rab11b-mediated regulatory mechanism for osteoclastogenesis by directly modulating the c-fms and RANK surface receptors in osteoclasts, thereby contributing to the maintenance of bone homeostasis.

DOI： 10.1016/j.bbamcr.2021.119096

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Exosome-Based Molecular Transfer Activity of Macrophage-Like Cells Involves Viability of Oral Carcinoma Cells: Size Exclusion Chromatography and Concentration Filter Method Reviewed International journal

Yanyin Lu, Takanori Eguchi, Chiharu Sogawa, Eman A. Taha, Manh Tien Tran, Toshiki Nara, Penggong Wei, Shiro Fukuoka, Takuya Miyawaki, Kuniaki Okamoto

Cells 10 ( 6 ) 1328 - 1328 2021.5

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG

Extracellular vesicles (EV) heterogeneity is a crucial issue in biology and medicine. In addition, tumor-associated macrophages are key components in cancer microenvironment and immunology. We developed a combination method of size exclusion chromatography and concentration filters (SEC-CF) and aimed to characterize different EV types by their size, cargo types, and functions. A human monocytic leukemia cell line THP-1 was differentiated to CD14-positive macrophage-like cells by stimulation with PMA (phorbol 12-myristate 13-acetate) but not M1 or M2 types. Using the SEC-CF method, the following five EV types were fractionated from the culture supernatant of macrophage-like cells: (i) rare large EVs (500–3000 nm) reminiscent of apoptosomes, (ii) EVs (100–500 nm) reminiscent of microvesicles (or microparticles), (iii) EVs (80–300 nm) containing CD9-positive large exosomes (EXO-L), (iv) EVs (20–200 nm) containing unidentified vesicles/particles, and (v) EVs (10–70 nm) containing CD63/HSP90-positive small exosomes (EXO-S) and particles. For a molecular transfer assay, we developed a THP-1-based stable cell line producing a GFP-fused palmitoylation signal (palmGFP) associated with the membrane. The THP1/palmGFP cells were differentiated into macrophages producing palmGFP-contained EVs. The macrophage/palmGFP-secreted EXO-S and EXO-L efficiently transferred the palmGFP to receiver human oral carcinoma cells (HSC-3/palmTomato), as compared to other EV types. In addition, the macrophage-secreted EXO-S and EXO-L significantly reduced the cell viability (ATP content) in oral carcinoma cells. Taken together, the SEC-CF method is useful for the purification of large and small exosomes with higher molecular transfer activities, enabling efficient molecular delivery to target cells.

DOI： 10.3390/cells10061328

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Macrophage-Derived Small Exosomes: Efficient Transmission and Cytotoxicity to Cancer Cells Reviewed

Yanyin Lu, Takanori Eguchi, Chiharu Sogawa, Eman A. Taha, Manh Tien Tran, Toshiki Nara, Penggong Wei, Shiro Fukuoka, Takuya Miyawaki, Kuniaki Okamoto

2021.4

Authorship：Last author Publisher：MDPI AG

Tumor-associated macrophages are a key component in the tumor microenvironment, secreting extracellular vesicles (EVs) such as exosomes and other various factors for intercellular communication. However, macrophage-derived EVs heterogeneity and their cytotoxicity to cancer cells has not been well understood. Here, we aimed to separately isolate various types of macro-phage-EVs by size exclusion chromatography (SEC) method and investigate EV transmission and cytotoxicity to oral cancer cells. For fluorescence-labeling of cellular and EV membranes, palmitoylation signal-fused GFP and tdTomato were expressed in THP-1 monocytic cells and HSC-3 oral cancer cells, respectively. We found that fluorescence-labeled EVs secreted by macrophages were highly transmissive to oral cancer cells than those from parental monocytic cells. In a co-culture system and conditioned medium (CM), a macrophage-secreted unidentified factor was cytotoxic to oral cancer cells. We fractionated macrophage-derived EVs by the SEC method and performed western blotting to characterize various EV types. Three fractions were characterized: small exosomes (EXO-S: &lt; 50 nm) fraction containing HSP90&alpha;, HSP90&beta;, CD63 (EV marker) and &beta;-actin; large exosomes (EXO-L: 50-200 nm) fraction containing CD9 (EV marker) and HSP90&beta;; large EVs (100-500 nm) fraction. Notably, the macrophage-derived small exosomes fraction was cytotoxic to oral cancer cells, while large exosomes and large EVs were not. There-fore, it was implicated that macrophage-derived small exosomes are cytotoxic with high trans-mission potential to cancer cells.

DOI： 10.20944/preprints202104.0464.v1

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Rab44 isoforms similarly promote lysosomal exocytosis, but exhibit differential localization in mast cells Reviewed

Tomoko Kadowaki, Yu Yamaguchi, Kohei Ogawa, Mitsuko Tokuhisa, Kuniaki Okamoto, Takayuki Tsukuba

FEBS Open Bio 11 ( 4 ) 1165 - 1185 2021.4

Gel-Free 3D Tumoroids with Stem Cell Properties Modeling Drug Resistance to Cisplatin and Imatinib in Metastatic Colorectal Cancer. Reviewed International journal

Chiharu Sogawa, Takanori Eguchi, Yuri Namba, Yuka Okusha, Eriko Aoyama, Kazumi Ohyama, Kuniaki Okamoto

Cells 10 ( 2 ) 2021.2

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

Researchers have developed several three-dimensional (3D) culture systems, including spheroids, organoids, and tumoroids with increased properties of cancer stem cells (CSCs), also called cancer-initiating cells (CICs). Drug resistance is a crucial issue involving recurrence in cancer patients. Many studies on anti-cancer drugs have been reported using 2D culture systems, whereas 3D cultured tumoroids have many advantages for assessing drug sensitivity and resistance. Here, we aimed to investigate whether Cisplatin (a DNA crosslinker), Imatinib (a multiple tyrosine kinase inhibitor), and 5-Fluorouracil (5-FU: an antimetabolite) alter the tumoroid growth of metastatic colorectal cancer (mCRC). Gene expression signatures of highly metastatic aggregative CRC (LuM1 cells) vs. low-metastatic, non-aggregative CRC (Colon26 and NM11 cells) were analyzed using microarray. To establish a 3D culture-based multiplexing reporter assay system, LuM1 was stably transfected with the Mmp9 promoter-driven ZsGreen fluorescence reporter gene, which was designated as LuM1/m9 cells and cultured in NanoCulture Plate®, a gel-free 3D culture device. LuM1 cells highly expressed mRNA encoding ABCG2 (a drug resistance pump, i.e., CSC/CIC marker), other CSC/CIC markers (DLL1, EpCAM, podoplanin, STAT3/5), pluripotent stem cell markers (Sox4/7, N-myc, GATA3, Nanog), and metastatic markers (MMPs, Integrins, EGFR), compared to the other two cell types. Hoechst efflux stem cell-like side population was increased in LuM1 (7.8%) compared with Colon26 (2.9%), both of which were markedly reduced by verapamil treatment, an ABCG2 inhibitor. Smaller cell aggregates of LuM1 were more sensitive to Cisplatin (at 10 μM), whereas larger tumoroids with increased ABCG2 expression were insensitive. Notably, Cisplatin (2 μM) and Imatinib (10 μM) at low concentrations significantly promoted tumoroid formation (cell aggregation) and increased Mmp9 promoter activity in mCRC LuM1/m9, while not cytotoxic to them. On the other hand, 5-FU significantly inhibited tumoroid growth, although not completely. Thus, drug resistance in cancer with increased stem cell properties was modeled using the gel-free 3D cultured tumoroid system. The tumoroid culture is useful and easily accessible for the assessment of drug sensitivity and resistance.

DOI： 10.3390/cells10020344

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Liquid-based 3D Cultured Tumoroids Modeling Resistance to Cisplatin and Imatinib in Metastatic Colorectal Cancer Reviewed

Chiharu Sogawa, Takanori Eguchi, Yuri Namba, Eriko Aoyama, Kazumi Ohyama, Kuniaki Okamoto

2020.12

Authorship：Last author Publisher：MDPI AG

Researchers have developed and used several three-dimensional (3D) culture systems, including spheroids, organoids, and tumoroids. Drug resistance is a crucial issue involving recurrence in cancer patients. Many studies on anticancer drugs have been done in 2D culture systems, where-as 3D cultured tumoroids have many advantages for assessing drug sensitivity and resistance. Here, we aim to investigate whether Cisplatin (a DNA crosslinker), Imatinib (a multiple tyro-sine kinase inhibitor), and 5-Fluorouracil (5-FU: an antimetabolite) alter tumoroid growth of metastatic colorectal cancer (mCRC). To establish a liquid-based 3D multiplexing reporter assay system, LuM1 (a murine mCRC cell line) was stably transfected with the Mmp9 promoter-driven ZsGreen reporter gene, which was designated as LuM1/m9 cells and cultured in NanoCulture Plate (NCP), a 3D culture device. The larger tumoroids were not sensitive to Cisplatin and ex-pressed ABCG2 (a marker of cancer stem cells, a.k.a. a drug efflux transporter), whereas smaller cell-aggregates were more sensitive to Cisplatin. Both Imatinib and Cisplatin significantly in-creased tumoroid growth (larger than 300 &mu;m2) and Mmp9 promoter activity and were not cytotoxic to the mCRC tumoroids. On the other hand, 5-FU was cytotoxic to the tumoroids and significantly inhibited tumoroid growth, although not completely. Thus, platinum resistance and imatinib resistance in mCRC were modeled using the liquid-based 3D cultured tumoroid system. The tumoroid culture is useful and easily accessible for the assessment of drug sensitivity and resistance.

DOI： 10.20944/preprints202012.0582.v1

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The Inhibitory Role of Rab11b in Osteoclastogenesis through Triggering Lysosome-Induced Degradation of c-Fms and RANK Surface Receptors Reviewed

Manh Tien Tran, Yuka Okusha, Yunxia Feng, Masatoshi Morimatsu, Penggong Wei, Chiharu Sogawa, Takanori Eguchi, Tomoko Kadowaki, Eiko Sakai, Hirohiko Okamura, Keiji Naruse, Takayuki Tsukuba, Kuniaki Okamoto

International Journal of Molecular Sciences 21 ( 24 ) 9352 - 9352 2020.12

Authorship：Last author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：MDPI AG

Rab11b, abundantly enriched in endocytic recycling compartments, is required for the establishment of the machinery of vesicle trafficking. Yet, no report has so far characterized the biological function of Rab11b in osteoclastogenesis. Using in vitro model of osteoclasts differentiated from murine macrophages like RAW-D cells or bone marrow-derived macrophages, we elucidated that Rab11b served as an inhibitory regulator of osteoclast differentiation sequentially via (i) abolishing surface abundance of RANK and c-Fms receptors; and (ii) attenuating nuclear factor of activated T-cells c1 (NFATc-1) upstream signaling cascades, following RANKL stimulation. Rab11b was localized in early and late endosomes, Golgi complex, and endoplasmic reticulum; moreover, its overexpression enlarged early and late endosomes. Upon inhibition of lysosomal function by a specific blocker, chloroquine (CLQ), we comprehensively clarified a novel function of lysosomes on mediating proteolytic degradation of c-Fms and RANK surface receptors, drastically ameliorated by Rab11b overexpression in RAW-D cell-derived osteoclasts. These findings highlight the key role of Rab11b as an inhibitor of osteoclastogenesis by directing the transport of c-Fms and RANK surface receptors to lysosomes for degradation via the axis of early endosomes-late endosomes-lysosomes, thereby contributing towards the systemic equilibrium of the bone resorption phase.

DOI： 10.3390/ijms21249352

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Papers - OKAMOTO Kuniaki