Yoshitaka Sekido

Aichi Cancer Center, Ōsaka, Ōsaka, Japan

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Publications (150)841.49 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The NF2 gene product Merlin is a protein containing ezrin, radixin, and moesin domains; it is a member of the 4.1 protein superfamily associated with the membrane cytoskeleton and also interacts with cell surface molecules. The mammalian Hippo cascade, a downstream signaling cascade of merlin, inactivates the Yes-associated protein (YAP). Yes-associated protein is activated by loss of the NF2 gene and functions as an oncogene in meningioma cells; however, the factors controlling YAP expression, phosphorylation, and subcellular localization in meningiomas have not been fully elucidated. Here, we demonstrate that merlin expression is heterogeneous in 1 NF2 gene-negative and 3 NF2 gene-positive World Health Organization grade I meningiomas. In the NF2 gene-positive meningiomas, regions with low levels of merlin (tumor rims) had greater numbers of cells with nuclear YAP versus regions with high merlin levels (tumor cores). Merlin expression and YAP phosphorylation were also affected by cell density in the IOMM-Lee and HKBMM human meningioma cell lines; nuclear localization of YAP was regulated by cell density and extracellular matrix (ECM) stiffness in IOMM-Lee cells. These results suggest that cell density and ECM stiffness may contribute to the heterogeneous loss of merlin and increased nuclear YAP expression in human meningiomas.
    06/2015; 74(7). DOI:10.1097/NEN.0000000000000211
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    ABSTRACT: Malignant mesothelioma (MM) shows inactivation of the BRCA1-associated protein 1 (BAP1) gene. In this study, we found BAP1 mutations in 5 (26%) of the 19 cell lines that we established from Japanese MM patients, and examined functional differences between the wild-type and mutant BAP1. First, we studied the subcellular localization of BAP1, demonstrating that the wild-type primarily resides in the nucleus and that the mutant BAP1 is found in the cytoplasm of the cells. Transduction of the wild-type BAP1 vector into MM cells with homozygous deletion (HD) at the BAP1 3' side resulted in both inhibition of cell proliferation and anchorage-independent cell growth, while BAP1 mutants of a missense or C-terminal truncated form showed impaired growth inhibitory effects. Next, we studied how BAP1 is involved in MM cell survival after irradiation (IR) which causes DNA damage. After IR, we found that both wild-type and mutant BAP1 were similarly phosphorylated and phospho-BAP1 localized mainly in the nucleus. Interestingly, BRCA1 proteins were decreased in the MM cells with BAP1 deletion, and that transduction of the mutants as well as wild-type BAP1 increased BRCA1 proteins, suggesting that BAP1 may promote DNA repair partly through stabilizing BRCA1. Furthermore, using the MM cells with BAP1 deletion, we found that the wild-type, and even a missense mutant, BAP1 conferred a higher survival rate after IR compared to the control vector. Our results suggested that, while wild-type BAP1 suppresses MM cell proliferation and restores cell survival after IR-damage, some mutant BAP1 may also moderately retain these functions. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Cancer Science 05/2015; DOI:10.1111/cas.12698 · 3.53 Impact Factor
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    PLoS ONE 04/2015; 10(4):e0123901. DOI:10.1371/journal.pone.0123901 · 3.23 Impact Factor
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    ABSTRACT: Both pro- and anti-oncogenic roles of miR-221 and miR-222 microRNAs are reported in several types of human cancers. A previous study suggested their oncogenic role in invasiveness in lung cancer, albeit only one cell line (H460) was used. To further evaluate involvement of miR-221 and miR-222 in lung cancer, we investigated the effects of miR-221 and miR-222 overexpression on six lung cancer cell lines, including H460, as well as one immortalized normal human bronchial epithelial cell line, HBEC4. miR-221 and miR-222 induced epithelial-to-mesenchymal transition (EMT)-like changes in a minority of HBEC4 cells but, unexpectedly, both the microRNAs rather suppressed their invasiveness. Consistent with the prior report, miR-221 and miR-222 promoted growth in H460; however, miR-221 suppressed growth in four other cell lines with no effects in one, and miR-222 suppressed growth in three cell lines but promoted growth in two. These are the first results to show tumor-suppressive effects of miR-221 and miR-222 in lung cancer cells, and we focused on clarifying the mechanisms. Cell cycle and apoptosis analyses revealed that growth suppression by miR-221 and miR-222 occurred through intra-S-phase arrest and/or apoptosis. Finally, lung cancer cell lines transfected with miR-221 or miR-222 became more sensitive to the S-phase targeting drugs, possibly due to an increased S-phase population. In conclusion, our data are the first to show tumor-suppressive effects of miR-221 and miR-222 on lung cancer, warranting testing their potential as therapeutics for the disease.
    Cancer Medicine 01/2015; 4(4). DOI:10.1002/cam4.412
  • Cancer Science 01/2015; 106(1). DOI:10.1111/cas.12590 · 3.53 Impact Factor
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    ABSTRACT: Malignant pleural mesothelioma (MPM) is a rare and highly aggressive neoplasm that arises from the pleural, pericardial or peritoneal lining. Although surgery, chemotherapy, radiotherapy and combinations of these therapies are used to treat MPM, the median survival of such patients is dismal. Therefore, there is a compelling need to develop novel therapeutics with different modes of action. Ganglioside GM2 is a glycolipid that has been shown to be overexpressed in various types of cancer. However, there is currently no literature regarding the use of GM2 as a potential therapeutic target in cases of MPM. In this study, we evaluated the efficacy of the anti-GM2 antibody BIW-8962 as an anti-MPM therapeutic using in vitro and in vivo assays. Consequently, the GM2 expression in the MPM cell lines was confirmed using flow cytometry. In addition, eight of 11 cell lines were GM2-positive (73%), although the GM2 expression was variable. BIW-8962 showed a significant ADCC activity against the GM2-expressing MPM cell line MSTO-211H, the effect of which depended on the antibody concentration and effector/target ratio. In an in vivo orthotropic mouse model using MSTO-211H cells, BIW-8962 significantly decreased the incidence and size of tumors. Additionally, the GM2 expression was confirmed in the MPM clinical specimens. Fifty-eight percent of the MPM tumors were positive for GM2, with individual variation in the intensity and frequency of staining. These data suggest that anti-GM2 antibodies may become a therapeutic option for MPM patients This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Cancer Science 11/2014; 106(1). DOI:10.1111/cas.12575 · 3.53 Impact Factor
  • European Journal of Cancer 11/2014; 50. DOI:10.1016/S0959-8049(14)70203-5 · 4.82 Impact Factor
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    ABSTRACT: Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) often provide dramatic responses in lung cancer patients with somatic EGFR mutation. However, acquired resistance to the drugs usually emerges within a few years. EGFR T790M secondary mutation, MET gene amplification, and transformation to small cell lung cancer are well-validated mechanisms that underlie acquisition of resistance to EGFR-TKIs. In addition, many molecular aberrations have been reported as candidates for mechanisms of acquired resistance to EGFR-TKIs. Amplification of the CRKL gene was reportedly observed in 1 of 11 lung cancer patients with EGFR mutations who acquired resistance to EGFR-TKI. This study is the first report, to our knowledge, that validated the role of CRKL gene amplification as a mechanism for acquisition of resistance to EGFR-TKIs.
    Lung cancer (Amsterdam, Netherlands) 06/2014; 85(2). DOI:10.1016/j.lungcan.2014.05.018 · 3.74 Impact Factor
  • W Gao · Y Gu · Z Li · H Cai · Q Peng · M Tu · Y Kondo · K Shinjo · Y Zhu · J Zhang · Y Sekido · B Han · Z Qian · Y Miao
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    ABSTRACT: Pancreatic ductal adenocarcinoma (PDAC) is a highly invasive cancer with a poor prognosis. Although microRNA (miRNA) transcripts have a crucial role in carcinogenesis and development, little information is known regarding the aberrant DNA methylation of miRNAs in PDAC. Using methylated DNA immunoprecipitation-chip analysis, we found that miR-615-5p was hypermethylated in its putative promoter region, which silenced its expression in PDAC cell lines. In addition, the overexpression of miR-615-5p in pancreatic cancer cells suppressed cell proliferation, migration and invasion. Insulin-like growth factor 2 (IGF2) is an imprinted gene, and its abnormal expression contributes to tumor growth. Here, we identified IGF2 as a target of miR-615-5p using a luciferase reporter assay. IGF2 upregulation in PDAC tissues was not correlated with a loss of imprinting but was inversely correlated with miR-615-5p downregulation. In addition, miR-615-5p suppressed pancreatic cancer cell proliferation, migration and invasion by directly targeting IGF2, and this effect could be reversed by co-transfection with IGF2. Furthermore, the stable overexpression of miR-615-5p inhibited tumor growth in vivo and was correlated with IGF2 expression. Using RNA sequencing, we further identified miR-615-5p as potentially targeting other genes, such as the proto-oncogene JUNB, and interfering with the insulin signaling pathway. Taken together, our results demonstrate that miR-615-5p was abnormally downregulated in PDAC cells due to promoter hypermethylation, which limited its inhibition of IGF2 and other target genes, thereby contributing to tumor growth, invasion and migration. These data demonstrate a novel and important role of miR-615-5p as a tumor suppressor in PDAC.Oncogene advance online publication, 28 April 2014; doi:10.1038/onc.2014.101.
    Oncogene 04/2014; DOI:10.1038/onc.2014.101 · 8.56 Impact Factor
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    ABSTRACT: The condensin complex is required for chromosome condensation during mitosis; however, the role of this complex during interphase is unclear. Neuroblastoma is the most common extracranial solid tumor of childhood, and it is often lethal. In human neuroblastoma, MYCN gene amplification is correlated with poor prognosis. This study demonstrates that the gene encoding the condensin complex subunit SMC2 is transcriptionally regulated by MYCN. SMC2 also transcriptionally regulates DNA damage response genes in cooperation with MYCN. Downregulation of SMC2 induced DNA damage and showed a synergistic lethal response in MYCN-amplified/overexpression cells, leading to apoptosis in human neuroblastoma cells. Finally, this study found that patients bearing MYCN-amplified tumors showed improved survival when SMC2 expression was low. These results identify novel functions of SMC2 in DNA damage response, and we propose that SMC2 (or the condensin complex) is a novel molecular target for the treatment of MYCN-amplified neuroblastoma.
    Cell cycle (Georgetown, Tex.) 02/2014; 13(7). DOI:10.4161/cc.27983 · 5.01 Impact Factor
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    ABSTRACT: Objectives Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) often provide dramatic responses in lung cancer patients with somatic EGFR mutation. However, acquired resistance to the drugs usually emerges within a few years. EGFR T790 M secondary mutation, MET gene amplification, and transformation to small cell lung cancer are well-validated mechanisms that underlie acquisition of resistance to EGFR-TKIs. In addition, many molecular aberrations have been reported as candidates for mechanisms of acquired resistance to EGFR-TKIs. Amplification of the CRKL gene was reportedly observed in 1 of 11 lung cancer patients with EGFR mutations who acquired resistance to EGFR-TKI. This study is the first report, to our knowledge, that validated the role of CRKL gene amplification as a mechanism for acquisition of resistance to EGFR-TKIs. Materials and Methods We analyzed CRKL gene copy numbers, using a quantitative real-time PCR method, in 2 in vitro acquired-resistance cell-line models: 11 clinical samples from patients who developed acquired resistance to EGFR-TKIs, and 39 tumor specimens obtained from 7 autopsy patients whose cancers acquired resistance to EGFR-TKIs. Mutational status of EGFR codon 790 and copy numbers for the MET gene were also determined. Results and Conclusion In analysis for in vitro models, CRKL gene copy numbers were identical between EGFR-TKI-sensitive parental cells and their acquired resistant descendant cells. In addition, we found no clinical tumor specimens with acquired EGFR-TKI resistance to harbor amplified CRKL genes. These results indicate that CRKL gene amplification is rare in acquisition of resistance to EGFR-TKIs in lung cancer patients with EGFR mutations.
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    ABSTRACT: Malignant mesothelioma (MM) is one of the most aggressive neoplasms usually associated with asbestos exposure and is highly refractory to current therapeutic modalities. MMs show frequent activation of a transcriptional coactivator Yes-associated protein (YAP), which is attributed to the neurofibromatosis type 2 (NF2)-Hippo pathway dysfunction, leading to deregulated cell proliferation and acquisition of a malignant phenotype. However, the whole mechanism of disordered YAP activation in MMs has not yet been well clarified. In the present study, we investigated various components of the NF2-Hippo pathway, and eventually found that MM cells frequently showed downregulation of LIM-domain protein AJUBA, a binding partner of large tumor suppressor type 2 (LATS2), which is one of the last-step kinases of the NF2-Hippo pathway. Although loss of AJUBA expression was independent of the alteration status of other Hippo pathway components, MM cell lines with AJUBA inactivation showed a more dephosphorylated (activated) level of YAP. Immunohistochemical analysis showed frequent downregulation of AJUBA in primary MMs, which was associated with YAP constitutive activation. We found that AJUBA transduction into MM cells significantly suppressed promoter activities of YAP-target genes, and the suppression of YAP activity by AJUBA was remarkably canceled by knockdown of LATS2. In connection with these results, transduction of AJUBA-expressing lentivirus significantly inhibited the proliferation and anchorage-independent growth of the MM cells that harbored ordinary LATS family expression. Taken together, our findings indicate that AJUBA negatively regulates YAP activity through the LATS family, and inactivation of AJUBA is a novel key mechanism in MM cell proliferation.Oncogene advance online publication, 16 December 2013; doi:10.1038/onc.2013.528.
    Oncogene 12/2013; 31(1). DOI:10.1038/onc.2013.528 · 8.56 Impact Factor
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    ABSTRACT: Ras-Association Family1A (RASSF1A) is a well-established tumor suppressor. Ten RASSF homologues comprise this family, and each member is considered a tumor suppressor. RASSF3 is one of the RASSF family members, but its function has not yet been clarified. Recently, we found that RASSF3 interacts with MDM2 and facilitates its ubiquitination, which induces apoptosis through p53 stabilization. However, the role of RASSF3 in human malignancies remains largely unknown. Ninety-five non-small cell lung cancer (NSCLC) patients from Nagoya University Hospital and 45 NSCLC patients from Aichi Cancer Center Hospital underwent pulmonary resection at each hospital, and lung cancer and corresponding non-cancerous lung tissues were collected. The expression levels of RASSF3 were analyzed using quantitative real-time reverse transcription PCR. We performed statistical analysis to investigate the correlation with RASSF3 expression and the clinicopathological characteristics. We also transfected RASSF3-siRNA into NSCLC cells, and performed motility assays to evaluate the influence on migration ability. RASSF3 expression levels were downregulated in 125 of a total 140 NSCLCs. In a multivariate logistic regression analysis, the low RASSF3 expression group below the median value was independently correlated with progressive phenotypes (lymph node metastasis and pleural invasion), non-adenocarcinoma histology and wild-type epidermal growth factor receptor (EGFR) status. In motility assays, RASSF3-knockdown NSCLC cells increased the migration rate compared to the control cells. We found that the expression levels of RASSF3 were frequently downregulated in NSCLCs. Downregulation of RASSF3 strongly correlated with the progressive phenotypes of NSCLCs and EGFR wild-type status. In vitro studies also suggested that RASSF3 downregulation increases migration ability of lung cancer cells. Together, our findings indicate RASSF3 is a candidate tumor suppressor gene of NSCLCs.
    Lung cancer (Amsterdam, Netherlands) 10/2013; 83(1). DOI:10.1016/j.lungcan.2013.10.014 · 3.74 Impact Factor
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    ABSTRACT: Cells of tumors associated with chronic inflammation frequently have altered patterns of DNA methylation, including hepatocellular carcinomas (HCCs). Chronic hepatitis has also been associated with aberrant DNA methylation, but little is known about their relationship. Pyrosequencing was used to determine the methylation status of cultured Huh7.5.1 hepatoma cells following hepatitis C virus (HCV) infection. We also studied mice with severe combined immunodeficiency carrying the urokinase-type plasminogen activator transgene controlled by an albumin promoter (uPA/SCID mice), in which up to 85% of hepatocytes were replaced by human hepatocytes (chimeric mice). Mice were given intravenous injections of hepatitis B virus (HBV) or HCV; liver tissues were collected and DNA methylation profiles were determined at different time points after infection. We also compared methylation patterns between paired samples of HCC and adjacent non-tumor liver tissues from patients. No reproducible changes in DNA methylation were observed following infection of Huh7.5.1 cells with HCV. Livers from HBV- and HCV-infected mice had genome-wide, time-dependent changes in DNA methylation, compared with uninfected uPA/SCID mice. There were changes in 160±63 genes in HBV-infected and 237±110 genes in HCV-infected mice. Methylation of 149 common genes increased in HBV- and HCV-infected mice; methylation of some of these genes also increased in HCC samples from patients, compared with non-tumor tissues. Expression of Ifng, which is expressed by natural killer (NK) cells, increased significantly in chimeric livers, in concordance with induction of DNA methylation, after infection with HBV or HCV. Induction of Ifng was reduced following administration of an inhibitor of NK cell function (anti-asialo GM1). In chimeric mice with humanized livers, infection with HBV and HCV appear to activate an NK cell-dependent innate immune response. This contributes to the induction and accumulation of aberrant DNA methylation in human hepatocytes.
    Gastroenterology 10/2013; 146(2). DOI:10.1053/j.gastro.2013.10.056 · 13.93 Impact Factor
  • Ichidai Tanaka · Hirotaka Osada · Makiko Fujii · Yoshitaka Sekido
    Cancer Research 08/2013; 73(8 Supplement):4313-4313. DOI:10.1158/1538-7445.AM2013-4313 · 9.28 Impact Factor
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    ABSTRACT: Like many other human cancers, the development of malignant mesothelioma is closely associated with a chronic inflammatory condition. Both macrophages and mesothelial cells play crucial roles in the inflammatory response caused by asbestos exposure. Here, we show that adipocytes can also contribute to asbestos-induced inflammation through dysregulated adipocytokine production. 3T3-L1 preadipocytes were differentiated into mature adipocytes prior to use. These cells took up asbestos fibers (chrysotile, crocidolite and amosite) but were more resistant to asbestos-induced injury than macrophages and mesothelial cells. Expression microarray analysis followed by reverse-transcription PCR revealed that adipocytes respond directly to asbestos exposure with an increased production of pro-inflammatory adipocytokines (e.g. MCP-1) while the production of anti-inflammatory adipocytokines (e.g. adiponectin) is suppressed. This was confirmed in epididymal fat pad of mice after intraperitoneal injection of asbestos fibers. Such dysregulated adipocytokine production favors the establishment of a pro-inflammatory environment. Furthermore, MCP-1 marginally promoted the growth of MeT-5A mesothelial cells and significantly enhanced the wound healing of Y-MESO-8A and Y-MESO-8D human mesothelioma cells. Our results suggest that increased levels of adipocytokines, such as MCP-1, can potentially contribute to the promotion of mesothelial carcinogenesis through the enhanced recruitment of inflammatory cells as well as a direct growth and migration stimulatory effect on mesothelial and mesothelioma cells. Taken together, our findings support a potential cancer-promoting role of adipocytes in asbestos-induced mesothelial carcinogenesis.
    Carcinogenesis 08/2013; DOI:10.1093/carcin/bgt267 · 5.27 Impact Factor
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    ABSTRACT: Tumor cell plasticity contributes to functional and morphological heterogeneity. To uncover the underlying mechanisms of this plasticity, we examined glioma stem-like cells (GSC) where we found that the biological interconversion between GSCs and differentiated non-GSCs is functionally plastic and accompanied by gain or loss of PRC2, a complex that modifies chromatin structure. PRC2 mediates lysine 27 trimethylation on histone H3 and in GSC it affected pluripotency or development associated genes (e.g. Nanog, Wnt1, BMP5) together with alterations in the subcellular localization of EZH2, a catalytic component of PRC2. Intriguingly, exogenous expression of EZH2-dNLS, which lacks nuclear localization sequence, impaired the repression of Nanog expression under differentiation conditions. RNAi-mediated attenuation or pharmacological inhibition of EZH2 had little to no effect on apoptosis or BrdU incorporation in GSCs, but it disrupted morphological interconversion and impaired GSC integration into the brain tissue, thereby improving survival of GSC-bearing mice. Pathological analysis of human glioma specimens revealed that the number of tumor cells with nuclear EZH2 is larger around tumor vessels and the invasive front, suggesting that nuclear EZH2 may help reprogram tumor cells in close proximity to this microenvironment. Our results indicate that epigenetic regulation by PRC2 is a key mediator of tumor cell plasticity, which is required for the adaptation of glioblastoma cells to their microenvironment. Thus, PRC2-targeted therapy may reduce tumor cell plasticity and tumor heterogeneity, offering a new paradigm for glioma treatment.
    Cancer Research 05/2013; 73(14). DOI:10.1158/0008-5472.CAN-13-0109 · 9.28 Impact Factor
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    ABSTRACT: Podoplanin (Aggrus), which is a type I transmembrane sialomucin-like glycoprotein, is highly expressed in malignant pleural mesothelioma (MPM). We previously reported the generation of a rat anti-human podoplanin Ab, NZ-1, which inhibited podoplanin-induced platelet aggregation and hematogenous metastasis. In this study, we examined the antitumor effector functions of NZ-1 and NZ-8, a novel rat-human chimeric Ab generated from NZ-1 including Ab-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity against MPM in vitro and in vivo. Immunostaining with NZ-1 showed the expression of podoplanin in 73% (11 out of 15) of MPM cell lines and 92% (33 out of 36) of malignant mesothelioma tissues. NZ-1 could induce potent ADCC against podoplanin-positive MPM cells mediated by rat NK (CD161a(+)) cells, but not murine splenocytes or human mononuclear cells. Treatment with NZ-1 significantly reduced the growth of s.c. established tumors of MPM cells (ACC-MESO-4 or podoplanin-transfected MSTO-211H) in SCID mice, only when NZ-1 was administered with rat NK cells. In in vivo imaging, NZ-1 efficiently accumulated to xenograft of MPM, and its accumulation continued for 3 wk after systemic administration. Furthermore, NZ-8 preferentially recognized podoplanin expressing in MPM, but not in normal tissues. NZ-8 could induce higher ADCC mediated by human NK cells and complement-dependent cytotoxicity as compared with NZ-1. Treatment with NZ-8 and human NK cells significantly inhibited the growth of MPM cells in vivo. These results strongly suggest that targeting therapy to podoplanin with therapeutic Abs (i.e., NZ-8) derived from NZ-1 might be useful as a novel immunotherapy against MPM.
    The Journal of Immunology 05/2013; 190(12). DOI:10.4049/jimmunol.1300448 · 5.36 Impact Factor
  • Yoshitaka Sekido
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    ABSTRACT: Malignant mesothelioma (MM) is an aggressive tumor arising primarily from the pleural or peritoneal cavities. It develops by asbestos exposure after a long latency, which is characterized by insidious growth and clinical presentation at an advanced stage of disease. MM is highly refractory to conventional therapies even with a combination of aggressive surgical intervention and multimodality strategies, with cure remaining elusive. Molecular genetic analysis has revealed several key genetic alterations which are responsible for the development and progression of MM. The CDKN2A/ ARF, NF2, and BAP1 genes are the most frequently mutated tumor suppressor genes detected in MM cells; the alterations of the latter two are relatively characteristic of MM. Merlin, which is encoded by NF2, regulates multiple cell signaling cascades including the Hippo and mTOR pathways which regulate cell proliferation and growth. BAP1 is involved in histone modification and its inactivation induces the disturbance of global gene expression profiling. The discovery of a new familial cancer syndrome with germline mutation of BAP1 also indicates the importance of genetic factors in MM susceptibility. Meanwhile, although frequent expression and functional activations of oncogene products such as receptor tyrosine kinases are observed in MM cells, activating mutations of these genes are rare. With further comprehensive genome analyses, new genetic and epigenetic alterations in MM cells are expected to be revealed more precisely, and the new knowledge based on them will be applied for developing new diagnostic tools and new target therapies against MMs.
    Carcinogenesis 05/2013; 34(7). DOI:10.1093/carcin/bgt166 · 5.27 Impact Factor
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    ABSTRACT: Malignant mesothelioma is an asbestos-related fatal disease with no effective cure. We studied whether a green tea polyphenol, epigallocathechin-3-gallate (EGCG), could induce cell death in five human mesothelioma cell lines. We found that EGCG induced apoptosis in all five mesothelioma cell lines in a dose-dependent manner. We further clarified the cell killing mechanism. EGCG induced reactive oxygen species (ROS), and impaired the mitochondrial membrane potential. As treatment with ROS scavengers, catalase and tempol, significantly inhibited the EGCG-induced apoptosis, ROS is considered to be responsible for the EGCG-induced apoptosis. Further, we found that EGCG induced autophagy, and that when autophagy was suppressed by chloroquine, the EGCG-induced cell death was enhanced. Taken together, these results suggest that EGCG has a great potential for the treatment of mesothelioma by inducing apoptosis and autophagy.
    Cancer Cell International 02/2013; 13(1):19. DOI:10.1186/1475-2867-13-19 · 1.99 Impact Factor

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6k Citations
841.49 Total Impact Points

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  • 2002–2015
    • Aichi Cancer Center
      Ōsaka, Ōsaka, Japan
    • University of Birmingham
      Birmingham, England, United Kingdom
  • 2001–2015
    • Nagoya University
      • • Division of of Internal Medicine
      • • Department of Preventive Medicine
      Nagoya, Aichi, Japan
  • 2013
    • Nagoya City University
      Nagoya, Aichi, Japan
  • 2011
    • Okayama University
      Okayama, Okayama, Japan
  • 1998
    • University of Texas at Dallas
      Richardson, Texas, United States
  • 1997–1998
    • University of Texas Southwestern Medical Center
      • Hamon Center for Therapeutic Oncology Research
      Dallas, Texas, United States