Toshiro Niki

Jichi Medical University, Totigi, Tochigi, Japan

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Publications (78)349 Total impact

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    ABSTRACT: The secondary epidermal growth factor receptor (EGFR) T790M mutation is the most prominent mechanism that confers resistance to first- or second-generation EGFR tyrosine kinase inhibitors (TKIs) in lung cancer treatment. Although third-generation EGFR TKIs can suppress the kinase activity of T790M-positive EGFR, they still cannot eradicate EGFR-mutated cancer cells. We previously reported that a subpopulation of EGFR-mutant lung adenocarcinomas depends on enhanced autophagy, instead of EGFR, for survival, and in this study we explore another mechanism that contributes to TKI resistance. We demonstrate here that an EGFR-mutant lung adenocarcinoma cell line, H1975 (L858R+T790M), has a subset of cells that exhibits an epithelial-mesenchymal transition (EMT) phenotype and can thrive in the presence of third-generation EGFR TKIs. These cells depend on not only autophagy but also on the isomerase Pin1 for survival in vitro, unlike their parental cells. The Pin1 protein was expressed in an EGFR-mutant lung cancer tissue that has undergone partial EMT and acquired resistance to EGFR TKIs, but not its primary tumor. These findings suggest that inhibition of Pin1 activity can be a novel strategy in lung cancer treatment.Laboratory Investigation advance online publication, 11 January 2016; doi:10.1038/labinvest.2015.155.
    No preview · Article · Jan 2016 · Laboratory Investigation
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    ABSTRACT: Although advanced esophageal squamous-cell carcinoma (ESCC) is treated using a multidisciplinary approach, outcomes remain unsatisfactory. The microenvironment of cancer cells has recently been shown to strongly influence the biologic properties of malignancies. We explored the effect of supernatant from esophageal fibroblasts on the cell growth and chemo-resistance of ESCC cell lines. We used 22 ESCC cell lines, isolated primary human esophageal fibroblasts and immortalized fibroblasts. We first examined cell proliferation induced by fibroblast supernatant. The effect of supernatant was evaluated to determine whether paracrine signaling induced by fibroblasts can influence the proliferation of cancer cells. Next, we examined the effects of adding growth factors HGF, FGF1, FGF7, and FGF10, to the culture medium of cancer cells. These growth factors are assumed to be present in the culture supernatants of fibroblasts and may exert a paracrine effect on the proliferation of cancer cells. We also examined the intrinsic role of HGF/MET and FGFs/FGFR in ESCC proliferation. In addition, we examined the inhibitory effect of lapatinib on ESCC cell lines and studied whether the fibroblast supernatants affect the inhibitory effect of lapatinib on ESCC cell proliferation. Finally, we tested whether the FGFR inhibitor PD-173074 could eliminate the rescue effect against lapatinib that was induced by fibroblast supernatants. The addition of fibroblast supernatant induces cell proliferation in the majority of cell lines tested. The results of experiments to evaluate the effects of adding growth factors and kinase inhibitors suggests that the stimulating effect of fibroblasts was attributable in part to HGF/MET or FGF/FGFR. The results also indicate diversity in the degree of dependence on HGF/MET and FGF/FGFR among the cell lines. Though lapanitib at 1 μM inhibits cell proliferation by more than 50% in the majority of the ESCC cell lines, fibroblast supernatant can rescue the growth inhibition of ESCC cells. However, the rescue effect is abrogated by co-treatment with FGFR inhibitor. These results demonstrate that cell growth of ESCC depends on diverse receptor tyrosine kinase signaling, in both cell-autonomous and cell-non-autonomous manners. The combined inhibition of these signals may hold promise for the treatment of ESCC.
    Full-text · Article · Dec 2015 · BMC Cancer
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    ABSTRACT: The switch/sucrose non-fermenting (SWI/SNF) complex has recently emerged as a novel tumor suppressor in various human cancers. In the present study, we analyzed the expression of multiple SWI/SNF subunits in primary non-small cell lung cancer (NSCLC). A total of 133 NSCLC, consisting of 25 squamous cell carcinomas (SCC), 70 adenocarcinomas (AD), 16 large cell carcinomas (LC), and 22 pleomorphic carcinomas (PL), were immunohistochemically examined for the expression of BRG1, BRM, BAF47, ARID1A, and ARID1B. The frequency at which reductions in the expression of BRG1 were observed was significantly higher in the LC-PL group (13/38, 34.2%) than in the SCC-AD group (7/95, 7.4%). Similarly, the frequency at which reductions in the expression of BRM were observed was significantly higher in the LC-PL group (17/38, 44.7%) than in the SCC-AD group (14/95, 14.7%). The loss of the expression of ARID1A, ARID1B, and BAF47 was observed only in a fraction of NSCLC cases. Furthermore, the frequency at which the concurrent loss of multiple subunits of the SWI/SNF complex was observed was significantly higher in the LC-PL group (10/38, 26.3%) than in the SCC-AD group (8/95, 8.4%). Collectively, these results indicate that the loss of the SWI/SNF complex was related to dedifferentiation in NSCLC.
    No preview · Article · Oct 2015 · Pathology International
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    ABSTRACT: We performed an immunohistochemical analysis of the expression of zinc-finger E-box binding homeobox 1 (ZEB1), a master regulator of epithelial-mesenchymal transition (EMT), and determined its relationship with E-cadherin in 157 non-small cell lung carcinomas (93 adenocarcinomas, 36 squamous cell carcinomas, 18 large cell carcinomas, and 10 pleomorphic carcinomas). Although the expression of E-cadherin was low in the subset of adenocarcinomas (10%) and squamous cell carcinomas (11%), ZEB1 expression was only observed in one case of squamous cell carcinoma and none of the adenocarcinomas. In contrast, the low expression of E-cadherin (50% and 90%, respectively) and the positive expression of ZEB1 (11% and 50%, respectively) were more frequently observed in poorly differentiated carcinomas (large cell carcinomas and pleomorphic carcinomas). Overall, the expression of ZEB1 was inversely correlated with that of E-cadherin. Furthermore, the distribution of ZEB1-positive cancer cells was more restricted than in the area in which the expression of E-cadherin was lost, and the former was detected within the latter. We concluded that the expression of ZEB1 was not necessarily associated with the low expression of E-cadherin in lung adenocarcinomas and squamous cell carcinomas. The expression of ZEB1 correlated with an undifferentiated and/or sarcomatoid morphology that may occur in the late stage of EMT.
    No preview · Article · Oct 2014 · Pathology International

  • No preview · Article · Oct 2014 · Cancer Research
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    ABSTRACT: The growth, invasiveness and metastasis of human cancers are determined not only by cancer cells, but also by their microenvironment. Activated stromal fibroblasts promote tumor progression by secreting growth factors. In the present study, we focused on interrelations between cancer and fibroblasts, the main component of tumor stroma. We retrospectively analyzed the relations of mortality to clinical, pathological, and α-smooth muscle actin (α-SMA) characteristics in 97 consecutive patients with esophageal squamous cell carcinoma (ESCC). In vitro, we used TE-11, KYSE150 and KYSE220 ESCC cell lines and isolated esophageal stromal fibroblasts, some of which were immortalized. Migration assays were conducted to assess the effects of fibroblasts on cancer-cell migration and 3-dimensional organotypic cultures. In vivo, TE-11 and KYSE220 cells plus immortalized fibroblasts were co-transplanted subcutaneously in Nod/Scid mice to assess the effects of fibroblasts on tumorigenicity. Clinicopathologically, the α-SMA expression of cancer stroma was correlated with venous invasion (p<0.01), nodal involvement (p=0.02), recurrence (p=0.01), and was a predictor of survival in patients with stage I and II ESCC (p=0.04). In vitro, the presence of fibroblasts strongly promoted the migration of TE-11, KYSE150 and KYSE220 cells. On organotypic culture, stromal invasion was observed only in the presence of immortalized fibroblasts. In vivo, tumors developed or grew in a fibroblast‑dependent manner after implantation. Our findings provide evidence that stromal fibroblasts and tumor cells interact to promote tumor progression in ESCC. In patients with earlier stage ESCC, α-SMA may be a predictor of mortality. Inhibition of paracrine systems associated with tumor fibroblasts may slow or reverse tumor progression, potentially leading to the development of new targeted therapies.
    No preview · Article · May 2014 · Oncology Reports
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    ABSTRACT: Although protein arginine methyltransferase 5 (PRMT5) has been implicated in various cancers, its expression pattern in lung adenocarcinoma cell lines and tissues has not been elucidated enough. In this study, microarray analysis of 40 non-small cell lung carcinoma cell lines showed that PRMT5 was a candidate histone methyltransferase gene that correlated with epithelial-mesenchymal transition. Immunocytochemical analysis of these cell lines indicated that the expression of PRMT5 was localized to the cytoplasm of E-cadherin-low and vimentin-high cell lines, while it was predominant in the nucleus and faint in the cytoplasm of E-cadherin-high and vimentin-low cell lines. Immunohistochemical analysis of lung adenocarcinoma cases (n = 130) revealed that the expression of PRMT5 was high in the cytoplasm of 47 cases (36%) and the nuclei of 34 cases (26%). The marked cytoplasmic expression of PRMT5 was frequently observed in high-grade subtypes (1 of 17 low-grade, 21 of 81 intermediate-grade, 25 of 32 high-grade, p < 0.0001) such as solid adenocarcinoma with the low expression of thyroid transcription factor-1 (TTF-1, the master regulator of lung) and low expression of cytokeratin 7 and E-cadherin (two markers for bronchial epithelial differentiation), while the high nuclear expression of PRMT5 was frequently noted in adenocarcinoma in situ, a low-grade subtype (6 of 17 low-grade, 25 of 81 intermediate-grade, 3 of 32 high-grade, p = 0.0444). The cytoplasmic expression of PRMT5 correlated with a poor prognosis (p = 0.0089). We herein highlighted the importance of PRMT5 expression, especially its cytoplasmic expression, in the process of epithelial-mesenchymal transition and loss of the bronchial epithelial phenotype of lung adenocarcinoma.
    No preview · Article · Mar 2014 · Human pathology
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    ABSTRACT: We retrospectively compared preoperative docetaxel, cisplatin, and fluorouracil (DCF) with cisplatin and fluorouracil (CF) in patients with esophageal cancer. The study included patients with advanced thoracic esophageal carcinoma (excluding T4 tumors) receiving preoperative chemotherapy. In the DCF group, five patients received two courses of treatment every 4 weeks, and 33 patients received three courses every 3 weeks. In the CF group, 38 patients received two courses of treatment every 4 weeks. Patients underwent curative surgery 4-5 weeks after completing chemotherapy. Patient demographic characteristics did not differ between the two study groups. The incidence of a grade 3 or 4 hematologic toxicity was significantly higher in the DCF group (33 patients) than in the CF group (five patients; P < 0.001). Curative resection was accomplished in 79% of patients in the DCF group and 66% in the CF group (P = 0.305). There were no in-hospital deaths. The incidence of perioperative complications did not differ between the groups. A grade 2 or 3 histological response was attained in a significantly higher proportion of patients in the DCF group (63%) than in the CF group (5%; P < 0.001). Progression-free survival and overall survival were significantly higher in the DCF group (P = 0.013, hazard ratio 0.473; P = 0.001, hazard ratio 0.344). In conclusion, a grade 3 or 4 hematologic toxicity was common in the DCF group but was managed by supportive therapy. Histological response rate, progression-free survival, and overall survival were significantly higher in the DCF group compared with the CF group.
    No preview · Article · Feb 2014 · Diseases of the Esophagus
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    ABSTRACT: Although cisplatin (CDDP) is a key drug in the treatment of esophageal squamous cell carcinoma (ESCC), acquired chemoresistance remains a major problem. Combination therapy may represent one strategy to overcome this resistance. Heat shock protein 90 (HSP90) is known to be overexpressed in several types of cancer cells, and its inhibition by small molecules, either alone or in combination, has shown promise in the treatment of solid malignancies. In the present study, we evaluated the synergistic effects of combining CDDP with the HSP90 inhibitor 17-N-allylamino-17-demethoxy geldanamycin (17-AAG) on two CDDP-resistant human esophageal squamous cancer cell lines, KYSE30 and KYSE150. The results obtained demonstrated the synergistic inhibitory effects of CDDP and 17-AAG on the growth of KYSE30 and KYSE150 cells. Cell growth and cell number were more effectively reduced by the combined treatment with CDDP and 17-AAG than by the treatment with either CDDP or 17-AAG alone. Western blotting revealed that the combined action of CDDP and 17-AAG cleaved poly (ADP-ribose) polymerase (PARP) and caspase-3, which demonstrated that the reduction in both cell growth and cell number was mediated by apoptosis. Time-course experiments showed that reduction in X-linked inhibitor of apoptosis protein (XIAP) and phosphorylated Akt were concomitant with apoptosis. The results of the present study demonstrate that 17-AAG synergizes with CDDP and induces apoptosis in CDDP-resistant ESCC cell lines, and also that modulation of the Akt/XIAP pathway may underlie this synergistic effect. Combination therapy with CDDP and an HSP90 inhibitor may represent a promising strategy to overcome CDDP resistance in ESCC.
    No preview · Article · Dec 2013 · Oncology Reports
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    ABSTRACT: Lung cancers harboring epidermal growth factor receptor (EGFR) mutations depend on constitutive activation of the kinase for survival. Although most EGFR-mutant lung cancers are sensitive to EGFR tyrosine kinase inhibitors (TKIs) and shrink in response to treatment, acquired resistance to TKI therapy is common. We demonstrate here that two EGFR-mutated lung adenocarcinoma cell lines, HCC827 and HCC4006, contain a subpopulation of cells that have undergone epithelial-to-mesenchymal transition and survive independent of activated EGFR. These EGFR-independent cancer cells, herein termed gefitinib-resistant (GR) cells, demonstrate higher levels of basal autophagy than their parental cells and thrive under hypoxic, reduced-serum conditions in vitro; this somewhat simulates the hypoxic environment common to cancerous tissues. We show that depletion of the essential autophagy gene, ATG5, by small interfering RNA (siRNA) or chloroquine, an autophagy inhibitor, markedly reduces GR cell viability under hypoxic conditions. Moreover, we show a significant elevation in caspase activity in GR cells following knockdown of ATG5. These results suggest that GR cells can evade apoptosis and survive in hostile, hypoxic environments with constant autophagic flux. We also show the presence of autophagosomes in some cancer cells from patient samples, even in untreated EGFR-mutant lung cancer tissue samples. Together, our results indicate that autophagy inhibitors alone or in combination with EGFR TKIs may be an effective approach for the treatment of EGFR-mutant lung cancers, where basal autophagy of some cancer cells is upregulated.Laboratory Investigation advance online publication, 12 August 2013; doi:10.1038/labinvest.2013.102.
    No preview · Article · Aug 2013 · Laboratory Investigation
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    ABSTRACT: Rearranged during transfection (RET) fusions have been newly identified in approximately 1% of patients with primary lung tumors. However, patient-derived lung cancer cell lines harboring RET fusions have not yet been established or identified, and therefore, the effectiveness of an RET inhibitor on lung tumors with endogenous RET fusion has not yet been studied. In this study, we report identification of CCDC6-RET fusion in the human lung adenocarcinoma cell line LC-2/ad. LC-2/ad showed distinctive sensitivity to the RET inhibitor, vandetanib, among 39 non-small lung cancer cell lines. The xenograft tumor of LC-2/ad showed cribriform acinar structures, a morphologic feature of primary RET fusion-positive lung adenocarcinomas. LC-2/ad cells could provide useful resources to analyze molecular functions of RET-fusion protein and its response to RET inhibitors.
    Full-text · Article · Dec 2012 · Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer
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    ABSTRACT: BRG1 and BRM, two core catalytic subunits in SWI/SNF chromatin remodeling complexes, have been suggested as tumor suppressors, yet their roles in carcinogenesis are unclear. Here, we present evidence that loss of BRG1 and BRM is involved in the progression of lung adenocarcinomas. Analysis of 15 lung cancer cell lines indicated that BRG1 mutations correlated with loss of BRG1 expression and that loss of BRG1 and BRM expression was frequent in E-cadherin-low and vimentin-high cell lines. Immunohistochemical analysis of 93 primary lung adenocarcinomas showed loss of BRG1 and BRM in 11 (12%) and 16 (17%) cases, respectively. Loss of expressions of BRG1 and BRM was frequent in solid predominant adenocarcinomas and tumors with low thyroid transcription factor-1 (TTF-1, master regulator of lung) and low cytokeratin7 and E-cadherin (two markers for bronchial epithelial differentiation). Loss of BRG1 was correlated with the absence of lepidic growth patterns and was mutually exclusive of EGFR mutations. In contrast, loss of BRM was found concomitant with lepidic growth patterns and EGFR mutations. Finally, we analyzed the publicly available dataset of 442 cases and found that loss of BRG1 and BRM was frequent in E-cadherin-low, TTF-1-low, and vimentin-high cases and correlated with poor prognosis. We conclude that loss of either of or both BRG1 and BRM is involved in the progression of lung adenocarcinoma into solid predominant tumors with features of epithelial mesenchymal transition and loss of the bronchial epithelial phenotype. BRG1 loss was specifically involved in the progression of EGFR wild-type, but not EGFR-mutant tumors.
    Full-text · Article · Nov 2012 · Cancer Science
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    ABSTRACT: Background: The effectiveness of neoadjuvant chemotherapy is evaluated on the basis of pathological responses and survival outcome, because achievement of a pathological complete response (pCR) is a good predictor of long-term survival. However, few studies have assessed the survival of breast cancer patients who received neoadjuvant chemotherapy including trastuzumab. Methods: The records of 161 breast cancer patients who received neoadjuvant chemotherapy between January 2006 and December 2011 were retrospectively reviewed. The patients were categorized into 4 subgroups on the basis of the status of the estrogen receptor (ER), the progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). HER2-positive patients received trastuzumab-based regimens. Pathological responses and survival were analyzed on the basis of breast cancer subtypes. Results: The pCR results obtained were: luminal A and B (ER and/or PR-positive, HER2-negative), 6.3 % (5/79 cases); luminal-HER2 hybrid (ER and/or PR-positive, HER2-positive), 25.0 % (5/20 cases); HER2-enriched (ER and PR-negative, HER2-positive), 63.0 % (17/27 cases); and triple-negative (ER and PR-negative, HER2-negative), 25.7 % (9/35 cases). Achievement of pCR was a good predictor of disease-free survival in the HER2-enriched group. Overall survival of patients with pCR was slightly, but not significantly, better in the HER2-enriched and triple-negative subgroups. Conclusion: Responses and survival after neoadjuvant chemotherapy including trastuzumab of patients with HER2-positive tumors differed among disease subtypes. Our findings suggest that disease subtype is an important determinant of the efficacy of neoadjuvant chemotherapy.
    No preview · Article · Oct 2012 · Breast Cancer
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    ABSTRACT: Adenosquamous carcinoma originating in the stomach is an unusual neoplasm with few existing histological studies. This study was aimed to gain insight into the histogenetic and clinicopathological characteristics of gastric cancer with squamous cell carcinoma (SCC) components. From January 2001 to June 2010 a total of 1735 patients underwent a resection of gastric cancer. Histopathologically, eight patients had adenocarcinoma containing SCC components, in which the proportion of SCC components was above 25% of the total tumor mass in four patients. The immunohistochemical and clinicopathological characteristics of these eight patients were analyzed. The median survival duration was 22 months. Adenocarcinoma was present at the superficial layer of all tumors and SCC was primarily present at sites with deep invasion. Immunohistochemically, adenocarcinoma components were positive for cytokeratin (CK) 8/18/19 and CK7 in all cases. SCC components were positive for carcinoembryonic antigen and CK7 in more than 60% of patients. Expression patterns of p53 product were identical in both components. SCC components were positive for 34βE12 and adenocarcinoma components were negative for 34βE12 in all patients. SCC components are derived from squamous metaplasia in a pre-existing adenocarcinoma. A gastric adenocarcinoma with SCC components is associated with various patterns of metastasis and both SCC and adenocarcinoma components have the potential for metastasis. Gastric cancer with SCC components is a clinically aggressive tumor.
    No preview · Article · Aug 2012 · Journal of Digestive Diseases

  • No preview · Article · Jun 2012 · Cancer Research

  • No preview · Article · Jun 2012 · Cancer Research

  • No preview · Article · Jun 2012 · Cancer Research
  • Daisuke Matsubara · Toshiro Niki

    No preview · Article · Apr 2012 · Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer
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    ABSTRACT: The role of human papillomavirus (HPV) in the development of lung and esophageal cancer remains inconclusive, which is in contrast to the established role HPV plays in the development of uterine cervical cancer. One of the reasons for this is the difference among reported HPV infection rates in these cancers. An analysis of 485 lung and esophageal cancers (176 lung squamous cell carcinoma, 128 lung adenocarcinoma, 181 esophageal carcinoma) in eight institutions in Asia (Tokyo, Kochi, Kagoshima, and Okinawa, Japan; Seoul and Daegu, Korea; Changhua, Republic of China (Taiwan); Singapore, Singapore) was carried out in order to clarify infection rates with HPV. Samples were examined in one laboratory of the Department of Pathology, the University of Tokyo, Japan in order to avoid inter-laboratory variation using a combination of polymerase chain reaction and in situ hybridization (ISH). HPV was found in 6.3%, 7%, and 9.4% of patients with lung squamous cell carcinoma, lung adenocarcinoma, and esophageal cancer, respectively. Among the geographic areas surveyed, Kagoshima exhibited a significantly higher prevalence of HPV infection in cases of esophageal carcinoma (24.1%). There was no geographical difference in the infection rates of HPV in lung carcinomas. Subtype-specific ISH was also performed, which identified the high-risk HPV types 16/18 in the majority (75.7%) of the patients with lung and esophageal cancer positive for HPV.
    No preview · Article · Aug 2011 · Journal of Medical Virology

  • No preview · Article · Jul 2011 · Cancer Research

Publication Stats

4k Citations
349.00 Total Impact Points


  • 2006-2015
    • Jichi Medical University
      • • Division of Integrative Pathology
      • • Department of Pathology
      • • Division of Pulmonary Medicine
      Totigi, Tochigi, Japan
  • 2004-2008
    • The University of Tokyo
      • Department of Pathology
      Edo, Tōkyō, Japan
    • Kyorin University
      • School of Medicine
      Edo, Tōkyō, Japan
  • 1998-2002
    • National Cancer Center, Japan
      • Center for Cancer Control and Information Services
      Edo, Tōkyō, Japan
  • 2001
    • National Hospital Organization Kyushu Cancer Center
      Hukuoka, Fukuoka, Japan