Faculty Profiles - SHIEN Kazuhiko

β-1,3-Galactosyl-O-Glycosyl-Glycoprotein β-1,6-N-Acetylglucosaminyltransferase 3 Increases MCAM Stability, Which Enhances S100A8/A9-Mediated Cancer Motility. Reviewed International journal

I Wayan Sumardika, Chen Youyi, Eisaku Kondo, Yusuke Inoue, I Made Winarsa Ruma, Hitoshi Murata, Rie Kinoshita, Ken-Ichi Yamamoto, Shuta Tomida, Kazuhiko Shien, Hiroki Sato, Akira Yamauchi, Junichiro Futami, Endy Widya Putranto, Toshihiko Hibino, Shinichi Toyooka, Masahiro Nishibori, Masakiyo Sakaguchi

Oncology research 26 ( 3 ) 431 - 444 2018.4

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

We previously identified novel S100A8/A9 receptors, extracellular matrix metalloproteinase inducer (EMMPRIN), melanoma cell adhesion molecule (MCAM), activated leukocyte cell adhesion molecule (ALCAM), and neuroplastin (NPTN) β, that are critically involved in S100A8/A9-mediated cancer metastasis and inflammation when expressed at high levels. However, little is known about the presence of any cancer-specific mechanism(s) that modifies these receptors, further inducing upregulation at protein levels without any transcriptional regulation. Expression levels of glycosyltransferase-encoding genes were examined by a PCR-based profiling array followed by confirmation with quantitative real-time PCR. Cell migration and invasion were assessed using a Boyden chamber. Western blotting was used to examine the protein level, and the RNA level was examined by Northern blotting. Immunohistochemistry was used to examine the expression pattern of β-1,3-galactosyl-O-glycosyl-glycoprotein β-1,6-N-acetylglucosaminyltransferase 3 (GCNT3) and MCAM in melanoma tissue. We found that GCNT3 is overexpressed in highly metastatic melanomas. Silencing and functional inhibition of GCNT3 greatly suppressed migration and invasion of melanoma cells, resulting in the loss of S100A8/A9 responsiveness. Among the novel S100A8/A9 receptors, GCNT3 favorably glycosylates the MCAM receptor, extending its half-life and leading to further elevation of S100A8/A9-mediated cellular motility in melanoma cells. GCNT3 expression is positively correlated to MCAM expression in patients with high-grade melanomas. Collectively, our results showed that GCNT3 is an upstream regulator of MCAM protein and indicate the possibility of a potential molecular target in melanoma therapeutics through abrogation of the S100A8/A9-MCAM axis.

DOI： 10.3727/096504017X15031557924123

Antitumor activity of pan‐ HER inhibitors in HER 2‐positive gastric cancer Reviewed International journal

Takahiro Yoshioka, Kazuhiko Shien, Kei Namba, Hidejiro Torigoe, Hiroki Sato, Shuta Tomida, Hiromasa Yamamoto, Hiroaki Asano, Junichi Soh, Kazunori Tsukuda, Takeshi Nagasaka, Toshiyoshi Fujiwara, Shinichi Toyooka

Cancer Science 109 ( 4 ) 1166 - 1176 2018.4

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

Molecularly targeted therapy has enabled outstanding advances in cancer treatment. Whereas various anti-human epidermal growth factor receptor 2 (HER2) drugs have been developed, trastuzumab is still the only anti-HER2 drug presently available for gastric cancer. In this study, we propose novel treatment options for patients with HER2-positive gastric cancer. First, we determined the molecular profiles of 12 gastric cancer cell lines, and examined the antitumor effect of the pan-HER inhibitors afatinib and neratinib in those cell lines. Additionally, we analyzed HER2 alteration in 123 primary gastric cancers resected from Japanese patients to clarify possible candidates with the potential to respond to these drugs. In the drug sensitivity analysis, both afatinib and neratinib produced an antitumor effect in most of the HER2-amplified cell lines. However, some cells were not sensitive to the drugs. When the molecular profiles of the cells were compared based on the drug sensitivities, we found that cancer cells with lower mRNA expression levels of IGFBP7, a tumor suppressor gene that inhibits the activation of insulin-like growth factor-1 receptor (IGF-1R), were less sensitive to pan-HER inhibitors. A combination therapy consisting of pan-HER inhibitors and an IGF-1R inhibitor, picropodophyllin, showed a notable synergistic effect. Among 123 clinical samples, we found 19 cases of HER2 amplification and three cases of oncogenic mutations. In conclusion, afatinib and neratinib are promising therapeutic options for the treatment of HER2-amplified gastric cancer. In addition to HER2 amplification, IGFBP7 might be a biomarker of sensitivity to these drugs, and IGF-1R-targeting therapy can overcome drug insensitiveness in HER2-amplified gastric cancer.

DOI： 10.1111/cas.13546

【肺癌の集学的治療の現況】局所進行肺癌における集学的治療局所進行非小細胞肺癌に対する術前導入化学放射線療法後手術

三浦章博, 宗淳一, 枝園和彦, 山本寛斉, 豊岡伸一

胸部外科 71 ( 4 ) 270 - 277 2018.4

[Induction Chemoradiotherapy for Locally Advanced Non-small Cell Lung Cancer]. Reviewed

Miura A, Soh J, Shien K, Yamamoto H, Toyooka S

Kyobu geka. The Japanese journal of thoracic surgery 71 ( 4 ) 270 - 277 2018.4

Tumor-suppressive effect of LRIG1, a negative regulator of ErbB, in non-small cell lung cancer harboring mutant EGFR. Reviewed International journal

Torigoe H, Yamamoto H, Sakaguchi M, Youyi C, Namba K, Sato H, Shien K, Soh J, Suzawa K, Tomida S, Tsukuda K, Miyoshi S, Toyooka S

Carcinogenesis 39 ( 5 ) 719 - 727 2018.3

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

Epidermal growth factor receptor (EGFR) is a member of the ErbB (HER) family that is known to play important roles in the pathogenesis of various human cancers. Mutations of the EGFR gene are commonly found as oncogenic driver mutations and have been targeted for treatment of non-small cell lung cancer (NSCLC). Leucine-rich repeat and immunoglobulin-like domain protein-1 (LRIG1) is a cell-surface protein that is known as a negative regulator of the ErbB (HER) family. In this study, we first confirmed that the expression levels of LRIG1 were much lower in NSCLC than in non-malignant cells or tissues. Next, we focused on the effect of LRIG1 in NSCLC. For this purpose, we established clones stably overexpressing LRIG1, using EGFR-mutant (HCC827, HCC4011 and NCI-H1975) and wild-type (A549) cells. Transfection of LRIG1 was associated with a decrease in the expression and phosphorylation levels of EGFR in the HCC827, HCC4011 and NCI-H1975 cells. It was also associated with strong suppression of the cell proliferative, invasive, migratory and tumorigenic potential of the HCC827 cells. On the other hand, no such effects were observed in the A549 cells. In addition, LRIG1 also downregulated the expression and phosphorylation levels of other tyrosine kinase receptors, such as HER2, HER3, MET and IGF-1R, and prevented the epithelial-to-mesenchymal transition induced by TGF-β in the HCC827 cells. These findings suggest that LRIG1 exerts important tumor-suppressive effects in EGFR-mutant NSCLC and has the potential to become a novel therapeutic target for EGFR-mutant NSCLC.

DOI： 10.1093/carcin/bgy044

Development of novel biologics for cancer metastasis via prevention of extracellular S100A8/A9 function Reviewed

Kinoshita Rie, Yamauchi Akira, Shien Kazuhiko, Tomida Shuta, Toyooka Shinichi, Kondo Eisaku, Sakaguchi Masakiyo

CANCER SCIENCE 109 1017 2018.1

Therapeutic potential of targeting S100A11 in malignant pleural mesothelioma Reviewed International journal

Hiroki Sato, Masakiyo Sakaguchi, Hiromasa Yamamoto, Shuta Tomida, Keisuke Aoe, Kazuhiko Shien, Takahiro Yoshioka, Kei Namba, Hidejiro Torigoe, Junichi Soh, Kazunori Tsukuda, Hiroyuki Tao, Kazunori Okabe, Shinichiro Miyoshi, Harvey I. Pass, Shinichi Toyooka

Oncogenesis 7 ( 1 ) 11 - 11 2018.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Nature

Malignant pleural mesothelioma (MPM) is an aggressive tumor with an unfavorable prognosis. The standard therapeutic approaches are limited to surgery, chemotherapy, and radiotherapy. Because the consequent clinical outcome is often unsatisfactory, a different approach in MPM treatment is required. S100A11, a Ca2+-binding small protein with two EF-hands, is frequently upregulated in various human cancers. Interestingly, it has been found that intracellular and extracellular S100A11 have different functions in cell viability. In this study, we focused on the impact of extracellular S100A11 in MPM and explored the therapeutic potential of an S100A11-targeting strategy. We examined the secretion level of S100A11 in various kinds of cell lines by enzyme-linked immunosorbent assay. Among them, six out of seven MPM cell lines actively secreted S100A11, whereas normal mesothelial cell lines did not secrete it. To investigate the role of secreted S100A11 in MPM, we inhibited its function by neutralizing S100A11 with an anti-S100A11 antibody. Interestingly, the antibody significantly inhibited the proliferation of S100A11-secreting MPM cells in vitro and in vivo. Microarray analysis revealed that several pathways including genes involved in cell proliferation were negatively enriched in the antibody-treated cell lines. In addition, we examined the secretion level of S100A11 in various types of pleural effusions. We found that the secretion of S100A11 was significantly higher in MPM pleural effusions, compared to others, suggesting the possibility for the use of S100A11 as a biomarker. In conclusion, our results indicate that extracellular S100A11 plays important roles in MPM and may be a therapeutic target in S100A11-secreting MPM.

DOI： 10.1038/s41389-017-0017-3

β-1,3-Galactosyl-

Sumardika, I. W., Youyi, C., Kondo, E., Inoue, Y., Ruma, I. M. W., Murata, H., Kinoshita, R., Yamamoto, K. I., Tomida, S., Shien, K., Sato, H., Yamauchi, A., Futami, J., Putranto, E. W., Hibino, T., Toyooka, S., Nishibori, M., Sakaguchi, M.

Oncol Res 26 ( 3 ) 2018

JAK1/STAT3 Activation through a Proinflammatory Cytokine Pathway Leads to Resistance to Molecularly Targeted Therapy in Non-Small Cell Lung Cancer. Reviewed International journal

Kazuhiko Shien

Molecular cancer therapeutics 16 ( 10 ) 2234 - 2245 2017.10

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ASSOC CANCER RESEARCH

Molecularly targeted drugs have yielded significant therapeutic advances in oncogene-driven non-small cell lung cancer (NSCLC), but a majority of patients eventually develop acquired resistance. Recently, the relation between proinflammatory cytokine IL6 and resistance to targeted drugs has been reported. We investigated the functional contribution of IL6 and the other members of IL6 family proinflammatory cytokine pathway to resistance to targeted drugs in NSCLC cells. In addition, we examined the production of these cytokines by cancer cells and cancer-associated fibroblasts (CAF). We also analyzed the prognostic significance of these molecule expressions in clinical NSCLC samples. In NSCLC cells with acquired resistance to targeted drugs, we observed activation of the IL6-cytokine pathway and STAT3 along with epithelial-to-mesenchymal transition (EMT) features. In particular, IL6 family cytokine oncostatin-M (OSM) induced a switch to the EMT phenotype and protected cells from targeted drug-induced apoptosis in OSM receptors (OSMRs)/JAK1/STAT3-dependent manner. The cross-talk between NSCLC cells and CAFs also preferentially activated the OSM/STAT3 pathway via a paracrine mechanism and decreased sensitivity to targeted drugs. The selective JAK1 inhibitor filgotinib effectively suppressed STAT3 activation and OSMR expression, and cotargeting inhibition of the oncogenic pathway and JAK1 reversed resistance to targeted drugs. In the analysis of clinical samples, OSMR gene expression appeared to be associated with worse prognosis in patients with surgically resected lung adenocarcinoma. Our data suggest that the OSMRs/JAK1/STAT3 axis contributes to resistance to targeted drugs in oncogene-driven NSCLC cells, implying that this pathway could be a therapeutic target. Mol Cancer Ther; 16(10); 2234-45. ©2017 AACR.

DOI： 10.1158/1535-7163.mct-17-0148

Elacridar, a third-generation ABCB1 inhibitor, overcomes resistance to docetaxel in non-small cell lung cancer. Reviewed International journal

Kazuhiko Shien

Oncology letters 14 ( 4 ) 4349 - 4354 2017.10

Language：English Publishing type：Research paper (scientific journal) Publisher：SPANDIDOS PUBL LTD

Docetaxel is a third-generation chemotherapeutic drug that is widely used in the treatment of patients with non-small cell lung cancer (NSCLC). However, the majority of patients with NSCLC eventually acquire resistance to the treatment. In the present study, the mechanism of acquired resistance to docetaxel treatment in lung cancer cells was investigated. The three NSCLC cell lines, H1299 with wild-type epidermal growth factor receptor (EGFR), EGFR-mutant HCC4006 and HCC827, and experimentally established docetaxel-resistant (DR) cells, H1299-DR, HCC827-DR, and HCC4006-DR were used with stepwise increases in concentrations of docetaxel. It was demonstrated that the established cell lines showed resistance to docetaxel and EGFR-tyrosine kinase inhibitors (TKIs). Molecular analysis revealed that all of the resistant cell lines highly expressed ATP binding cassette subfamily B member 1 (ABCB1), which is also known as P-glycoprotein or MDR1. Furthermore, HCC827-DR and HCC4006-DR cells exhibited a cancer stem cell-like marker and epithelial-to-mesenchymal transition features, respectively. Elacridar (GF120918), a third-generation inhibitor of ABCB1, was able to overcome resistance to docetaxel. Additionally, knockdown of ABCB1 using small interfering RNA (si)-ABCB1 recovered sensitivity to docetaxel. However, elacridar and si-ABCB1 could not recover sensitivity to EGFR-TKIs in established resistant cells. The results of the present study revealed that docetaxel-resistant NSCLC cells also acquired cross-resistance to EGFR-TKI therapy through mechanisms other than ABCB1, that ABCB1 serves an important role in acquired resistance to docetaxel in lung cancer, and that combination therapy with elacridar can overcome ABCB1-mediated docetaxel resistance.

DOI： 10.3892/ol.2017.6678

Induction chemoradiotherapy using docetaxel and cisplatin with definitive-dose radiation followed by surgery for locally advanced non-small cell lung cancer. Reviewed International journal

Torigoe H, Soh J, Tomida S, Namba K, Sato H, Katsui K, Hotta K, Shien K, Yamamoto H, Yamane M, Kanazawa S, Kiura K, Miyoshi S, Toyooka S

Journal of thoracic disease 9 ( 9 ) 3076 - 3086 2017.9

Language：English Publishing type：Research paper (scientific journal) Publisher：AME PUBL CO

Background: Induction chemoradiotherapy (CRT) followed by surgery is a therapeutic option for locally advanced non-small cell lung cancer (LA-NSCLC). Typically, around 40-50 Gy of radiation is applied as the induction-dose; however, a definitive-dose (DD) of radiation (60 Gy or higher) is occasionally applied to increase local control. We investigated the impact of induction CRT with DD radiation in LA-NSCLC patients treated with a single regimen of docetaxel and cisplatin. Methods: We reviewed 110 patients with LA-NSCLC who underwent induction CRT followed by surgery using a single regimen (docetaxel and cisplatin) between January 1999 and December 2014 at our hospital. The clinical outcomes of a DD group (60 Gy or higher, n=11) and a non-DD group (less than 60 Gy, n=99) were investigated using a propensity score (PS)-matched analysis. Results: An advanced clinical stage was significantly more common in the DD group than in the non-DD group (P=0.033). Before and after the PS-matching based on seven factors including clinical stage, there was no significant difference in the rates of postoperative (PO) complication, mortality, 5-year overall survival (OS), or 5-year recurrence-free survival (RFS) between the two groups. After the PS-matching, the pathological complete response (CR) rate was significantly higher in the DD group than in the non-DD group [50% (n=5/10) vs. 0% (n=0/10), P=0.033]. Conclusions: Induction CRT followed by surgery using docetaxel and cisplatin with DD radiation can be performed safely and is associated with a higher pathological CR rate than that attained using non-DD radiation in LA-NSCLC patients.

DOI： 10.21037/jtd.2017.08.87

ß-1,3-galactosyl-O-glycosyl-glycoprotein ß-1,6-N-acetylglucosaminyltransferase 3 Increases MCAM Stability, Which Enhances S100A8/A9-Mediated Cancer Motility. Reviewed International journal

Kazuhiko Shien

Oncology research 26 ( 3 ) 431 - 444 2017.9

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

DOI： 10.3727/096504017x15031557924123

Advantage of Induction Chemoradiotherapy for Lung Cancer in Securing Cancer-Free Bronchial Margin. Reviewed International journal

Kazuhiko Shien

The Annals of thoracic surgery 104 ( 3 ) 971 - 978 2017.9

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

BACKGROUND: Bronchoplasty is a useful procedure for preserving pulmonary function. For this procedure, it is critical to secure the negative surgical margin for avoiding local recurrence. In this study, we examined the status of the surgical bronchial margin as well as the clinical outcomes in bronchoplasty with or without induction chemoradiotherapy (CRT) for non-small cell lung cancer (NSCLC). METHODS: The medical records of NSCLC patients who underwent bronchoplasty at our institution between January 1999 and September 2014 were reviewed. We compared the clinical outcomes of bronchoplasty with or without induction CRT. RESULTS: A total of 58 NSCLC patients were included in this study. Among these, 38 patients underwent primary surgical procedure with bronchoplasty and 20 patients underwent bronchoplasty after induction CRT. Intraoperative pathologic diagnosis for the surgical margin of the bronchus revealed that the patients in the primary surgical procedure group had a significantly higher rate of positive surgical margin than the induction CRT group (p = 0.023), requiring an additional bronchial resection to secure the negative margin. After additional resection of positive bronchial stumps, no significant difference was found in the rate of positive margin with postoperative histologic diagnosis between the two groups. In addition, no significant differences in the postoperative complication rate and overall and recurrence-free survivals were observed between the two groups. CONCLUSIONS: Our results suggest that induction CRT before surgical procedure may help ensure the intraoperative negative surgical margin of the bronchus. Our study also indicates that bronchoplasty after induction CRT is feasible in comparison with bronchoplasty in primary surgical procedure.

DOI： 10.1016/j.athoracsur.2017.03.045

Erratum to "Frequent methylation and oncogenic role of microRNA-34b/c in small-cell lung cancer" [Lung Cancer 76 (1) (2012) 32-38]. Reviewed

Tanaka N, Toyooka S, Soh J, Kubo T, Yamamoto H, Maki Y, Muraoka T, Shien K, Furukawa M, Ueno T, Asano H, Tsukuda K, Aoe K, Miyoshi S

Lung cancer (Amsterdam, Netherlands) 108 254 - 255 2017.6

Is tumor location an independent prognostic factor in locally advanced non-small cell lung cancer treated with trimodality therapy? Reviewed International journal

Kazuhiko Shien

Journal of thoracic disease 9 ( 5 ) E489-E491 - E491 2017.5

Targeting the miR-200c/LIN28B axis in acquired EGFR-TKI resistance non-small cell lung cancer cells harboring EMT features. Reviewed International journal

Kazuhiko Shien

Scientific reports 7 40847 - 40847 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

MicroRNA (miR)-200 family members (miR-200s) are frequently silenced in advanced cancer and have been implicated in the process of epithelial-to-mesenchymal transition (EMT). We previously reported that miR-200s were silenced through promoter methylation in acquired EGFR-tyrosine kinase inhibitor (TKI) resistant non-small cell lung cancer (NSCLC) cells harboring EMT features. In this study, we examined the functional role of miR-200s in NSCLC cells and investigated a novel approach to overcoming acquired EGFR-TKI resistance. In the analysis of NSCLC cell lines, each of the miR-200s expression-silenced cell lines showed promoter methylation. Significant correlations between miR-200c silencing and several oncogenic pathway alterations, including EMT-changes and LIN28B overexpression, were observed in the database analysis. In addition, EGFR-wild type cell lines had lower miR-200s expression levels than EGFR-mutant cell lines. The introduction of miR-200c using pre-miR-200c caused LIN28B suppression in cells with acquired EGFR-TKI resistance that harbored EMT features. Interestingly, both the introduction of miR-200c and the knockdown of LIN28B produced an antitumor effect in acquired EGFR-TKI resistance cells, whereas these manipulations were not effective in parental cells. The miR-200c/LIN28B axis plays an important role in cells with acquired resistance to EGFR-TKI that harbor EMT features and might be a useful therapeutic target for overcoming resistance.

DOI： 10.1038/srep40847

Distant Bystander Effect of REIC/DKK3 Gene Therapy Through Immune System Stimulation in Thoracic Malignancies. Reviewed International journal

Kazuhiko Shien

Anticancer research 37 ( 1 ) 301 - 307 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：INT INST ANTICANCER RESEARCH

BACKGROUND: Reduced expression in immortalized cell (REIC)/Dickkoph-3 (DKK3) is a tumor-suppressor gene, and its overexpression by adenovirus vector (Ad-REIC) exhibits a remarkable therapeutic effect on various human cancer types through a mechanism triggered by endoplasmic reticulum stress. MATERIALS AND METHODS: We examined the direct anti-tumor effect of Ad-REIC gene therapy on lung cancer and malignant mesothelioma cell lines in vitro, and the distant bystander effect using immunocompetent mouse allograft models with bilateral flank tumors. RESULTS: Ad-REIC treatment showed antitumor effect in many lung cancer and malignant mesothelioma cell lines in vitro. In an in vivo model, Ad-REIC treatment inhibited the growth not only of directly treated tumors but also of distant untreated tumors. By immunohistochemical analysis, infiltration of T-cells and natural killer (NK) cells and expression of the major histocompatibility complex (MHC) class I molecules were observed in bilateral tumors. CONCLUSION: Ad-REIC treatment not only had a direct antitumor effect but also an indirect bystander effect through stimulation of the immune system.

DOI： 10.21873/anticanres.11321

Yes1 signaling mediates the resistance to Trastuzumab/Lap atinib in breast cancer. Reviewed International journal

Kazuhiko Shien

PloS one 12 ( 2 ) e0171356 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：PUBLIC LIBRARY SCIENCE

BACKGROUND: Overexpression of human epidermal growth factor receptor 2 (HER2) is observed in approximately 15-23% of breast cancers and these cancers are classified as HER2-positive breast cancer. Trastuzumab is the first-line targeted therapeutic drug for HER2-positive breast cancer and has improved patient overall survival. However, acquired resistance to trastuzumab is still a critical issue in breast cancer treatment. We previously established a trastuzumab-resistant breast cancer cell line (named as BT-474-R) from a trastuzumab-sensitive HER2-amplified cell line BT-474. Lapatinib is also a molecular-targeted drug for HER2-positive breast cancer, which acquired the resistance to trastuzumab. Acquired resistance to lapatinib is also an issue to be conquered. METHODS: We established trastuzumab/lapatinib-dual resistant cell line (named as BT-474-RL2) by additionally treating BT-474-R with lapatinib. We analyzed the mechanisms of resistance to trastuzumab and lapatinib. Besides, we analyzed the effect of the detected resistance mechanism in HER2-positive breast cancer patients. RESULTS: Proto-oncogene tyrosine-protein kinase Yes1, which is one of the Src family members, was amplified, overexpressed and activated in BT-474-R and BT-474-RL2. Silencing of Yes1 by siRNA induced both BT-474-R and BT-474-RL2 to restore the sensitivity to trastuzumab and lapatinib. Pharmaceutical inhibition of Yes1 by the Src inhibitor dasatinib was also effective to restore the sensitivity to trastuzumab and lapatinib in the two resistant cell lines. Combination treatment with dasatinib and trastuzumab induced down-regulation of signaling molecules such as HER2 and Akt. Moreover, the combination treatments induced G1-phase cell-cycle arrest and apoptosis. Consistent with cell line data, high expression of Yes1 mRNA was correlated with worse prognosis in patients with HER2-positive breast cancer. CONCLUSION: Yes1 plays an important role in acquired resistance to trastuzumab and lapatinib in HER2-positive breast cancer. Our data suggest that pharmacological inhibition of Yes1 may be an effective strategy to overcome resistance to trastuzumab and lapatinib.

DOI： 10.1371/journal.pone.0171356

Interaction of cytokeratin 19 head domain and HER2 in the cytoplasm leads to activation of HER2-Erk pathway. Reviewed International journal

Kazuhiko Shien

Scientific reports 6 39557 - 39557 2016.12

Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

HER2 is a receptor tyrosine kinase and its upregulation via activating mutations or amplification has been identified in some malignant tumors, including lung cancers. Because HER2 can be a therapeutic target in HER2-driven malignancies, it is important to understand the molecular mechanisms of HER2 activation. In the current study, we identified that cytokeratin 19 (KRT19) binds to HER2 at the inside face of plasma membrane. HER2 and KRT19, which were concurrently introduced to a human embryonic kidney 293 T cells, revealed an association with each other and resulted in phosphorylation of HER2 with the subsequent activation of a downstream Erk-associated pathway. A binding assay revealed that both the NH2-terminal head domain of KRT19 and the COOH-terminal domain of HER2 were essential for their binding. To investigate the impact of the interaction between HER2 and KRT19 in lung cancer, we examined their expressions and localizations in lung cancers. We found that KRT19 was highly expressed in HER2-positive lung cancer cells, and KRT19 and HER2 were co-localized at the cell membrane. In conclusion, we found that KRT19 intracellularly binds to HER2, playing a critical role in HER2 activation.

DOI： 10.1038/srep39557