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Dive into the research topics where Ryuichiro Sekiya is active.

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Featured researches published by Ryuichiro Sekiya.


Human Pathology | 2012

Expression of CXCR4 indicates poor prognosis in patients with clear cell carcinoma of the ovary

Ryuichiro Sekiya; Hiroaki Kajiyama; Kotaro Sakai; Tomokazu Umezu; Mika Mizuno; Kiyosumi Shibata; Eiko Yamamoto; Sawako Fujiwara; Tetsuro Nagasaka; Fumitaka Kikkawa

Recent reports have shown that CXCR4 is expressed in various solid tumors and is involved in tumor development and metastasis. We examined the distribution and expression of this molecule in clear cell carcinoma of the ovary to elucidate its clinical significance. Paraffin sections from clear cell carcinoma of the ovary tissues (n = 42) were immunostained with CXCR4 antibody, and the staining intensities were evaluated. The clinicopathologic factors examined were age, FIGO (International Federation of Gynecology and Obstetrics) staging, preoperative value of cancer antigen 125 test, and residual tumor after cytoreductive surgery. Overall survival and progression-free survival were evaluated using the Kaplan-Meier method, and multivariate analysis was completed using Cox proportional hazards analysis. Of the 42 carcinomas, lower level CXCR4 immunoexpression was observed in 21 cases (50.0%) (CXCR4(low) group); and higher level immunoexpression, in 21 cases (50.0%) (CXCR4(high) group). Five-year overall survival was significantly poorer in the CXCR4(high) group than in the CXCR4(low) group (overall survival, CXCR4(low) group [90.2%], CXCR4(high) group [50.3%]; P = .0002). In addition, CXCR4(high) immunoexpression significantly predicted a poorer progression-free survival when compared with lower expression (5-year progression-free survival, CXCR4(low) group [90.5%], CXCR4(high) group [36.2%]; P < .0001). Furthermore, multivariate analyses including the age, preoperative cancer antigen 125 test value, FIGO stage, and CXCR4 expressions revealed that CXCR4(high) expression was an independent prognostic factor for poorer overall survival and progression-free survival of patients with clear cell carcinoma of the ovary (overall survival, P = .0011; progression-free survival, P = .0008, respectively). Our current study suggested that the assessment of CXCR4 immunoreactivity may be a useful prognostic indicator and that CXCR4 may play a critical role in the progression of clear cell carcinoma of the ovary.


OncoImmunology | 2016

Efficacy of glypican-3-derived peptide vaccine therapy on the survival of patients with refractory ovarian clear cell carcinoma

Shiro Suzuki; Jun Sakata; Fumi Utsumi; Ryuichiro Sekiya; Hiroaki Kajiyama; Kiyosumi Shibata; Fumitaka Kikkawa; Tetsuya Nakatsura

ABSTRACT Compared with other epithelial ovarian carcinoma subtypes, ovarian clear cell carcinoma (OCCC) has been recognized to show chemoresistance. Therefore, new treatment modalities are required for patients with OCCC that is refractory to chemotherapy. The carcinoembryonic antigen glypican-3 (GPC3) is expressed by approximately half of OCCC and is a promising immunotherapeutic target. The purpose of this study was to evaluate the effect of GPC3 peptide vaccine against refractory OCCC patients. We conducted a phase II trial with a GPC3-derived peptide vaccine in OCCC patients. Immunological responses were analyzed by ex vivo IFNγ ELISPOT assay. We also evaluated control subjects, who received best supportive care without vaccinations during the same period. Thirty-two patients with refractory OCCC were enrolled between July 2010 and September 2015, and underwent GPC3 peptide vaccination. Fifteen patients were vaccinated less than six times because their general condition progressively deteriorated, and 17 patients were vaccinated at least six times. Three patients showed a partial response as the best overall response. The GPC3 peptide vaccine induced a GPC3-specific CTL response in 15 out of 24 patients who had PBMCs collected three times or more. The prognosis of palliative care patients without GPC3 peptide vaccinations was significantly poorer than that of those with GPC3 peptide vaccinations (post cancer-treatment survival: p = 0.002). Although the disease control rate was not high, our results suggest that GPC3 peptide vaccinations may hold a significant impact to prolong survival of patients with refractory OCCC, allowing them to maintain quality of life with no serious toxicities.


Journal of Obstetrics and Gynaecology Research | 2014

Possible association between stem-like hallmark and radioresistance in human cervical carcinoma cells

Shoko Kumazawa; Hiroaki Kajiyama; Tomokazu Umezu; Mika Mizuno; S. Suzuki; Eiko Yamamoto; Hiroko Mitsui; Ryuichiro Sekiya; Kiyosumi Shibata; Fumitaka Kikkawa

We aimed to investigate the possibility of an association between a stem‐like hallmark and radiotherapeutic sensitivity in human cervical carcinoma cells.


Journal of Gynecologic Oncology | 2014

Survival benefit of taxane plus platinum in recurrent ovarian cancer with non-clear cell, non-mucinous histology

Hiroaki Kajiyama; Kiyosumi Shibata; Mika Mizuno; Tomokazu Umezu; S. Suzuki; Ryuichiro Sekiya; Kaoru Niimi; Hiroko Mitsui; Eiko Yamamoto; Michiyasu Kawai; Tetsuro Nagasaka; Fumitaka Kikkawa

Objective This study was conducted to examine the effects of front-line chemotherapy on overall survival (OS) and postrecurrence survival (PRS) of patients with recurrent ovarian cancer, when stratifying the histologic type. Methods Five hundred and seventy-four patients with recurrent ovarian cancer with sufficient clinical information, including front-line chemotherapy, were analyzed. The pathologic slides were evaluated by central pathologic review. The patients were divided into two groups: group A (n=261), who underwent taxane plus platinum, and group B (n=313), who underwent conventional platinum-based chemotherapy without taxanes. Results The median age was 54 years (range, 14 to 89 years). Group A had significantly better median OS (45.0 months vs. 30.3 months, p<0.001) and PRS (23.0 months vs. 13.0 months, p<0.001) compared to group B. The OS and PRS were similar between the groups in patients with clear cell or mucinous histology. In contrast, among patients with non-clear cell, non-mucinous histologies, the OS and PRS of group A were significantly better than those of group B (OS, p<0.001; PRS, p<0.001). Multivariable analyses revealed that, among patients with non-clear cell, non-mucinous histologies, chemotherapy including taxane and platinum was an independent predictor of favorable survival outcomes. Conversely, in patients with clear cell or mucinous histology, taxane-including platinum-based combination chemotherapy did not improve the OS and PRS compared to a conventional platinum-based regimen which did not include taxanes. Conclusion Since the emergence of taxane plus platinum, the prognosis of patients with recurrent ovarian cancer has improved. However, we here demonstrate that this improvement is limited to patients with non-clear cell, non-mucinous histologies.


Carcinogenesis | 2014

PLAGL2 regulates actin cytoskeletal architecture and cell migration.

Ryuichiro Sekiya; Masao Maeda; Hong Yuan; Eri Asano; Toshinori Hyodo; Hitodki Hasegawa; Satoko Ito; Kiyosumi Shibata; Michinari Hamaguchi; Fumitaka Kikkawa; Hiroaki Kajiyama; Takeshi Senga

Pleomorphic adenoma gene like-2 (PLAGL2), a member of the PLAG gene family, is a C2H2 zinc finger transcriptional factor that is involved in cellular transformation and apoptosis. In this report, we show that PLAGL2 is associated with the organization of stress fibers and with small guanosine triphosphatase (GTPase) activity. Depletion of PLAGL2 in two different ovarian cancer cell lines, ES-2 and HEY, induced activation of RhoA, whereas activity of Rac1 was suppressed. Organization of actin stress fibers and focal adhesions was significantly promoted by PLAGL2 knockdown in a RhoA-dependent manner. Conversely, exogenous expression of PLAGL2 in MDA-MB-231 cells, a breast cancer cell line, resulted in the activation of Rac1 and the inactivation of RhoA. In addition, PLAGL2 expression induced lamellipodia formation and disruption of stress fiber formation. Finally, we show that CHN1 expression is essential for Rac1 inactivation in PLAGL2-depleted cells. Our results demonstrate a crucial role of PLAGL2 in actin dynamics and give further insight into the role of PLAGL2 in cellular transformation and apoptosis.


Tumori | 2016

Feasibility and benefit of concurrent chemoradiotherapy for elderly patients with uterine cervical cancer.

Kazuto Nosaka; Kiyosumi Shibata; Fumi Utsumi; Kosuke Yoshida; Kaoru Niimi; Ryuichiro Sekiya; S. Suzuki; Hiroaki Kajiyama; Fumitaka Kikkawa

Background Elderly patients with uterine cervical cancer reportedly have a poorer prognosis than younger patients. Until now, the benefit of concurrent chemoradiotherapy (CCRT) for elderly patients has been considered limited. Methods We retrospectively analyzed 49 women with cervical cancer aged >70 years primarily treated with radiotherapy (RT) or CCRT in our institute between 2003 and 2014. Treatment compliance, toxicity, and survival benefit were analyzed. Results A total of 49 patients were identified in this retrospective analysis. Twenty patients with a median age of 75.4 years (range 70–77) were treated with CCRT and 29 patients with a median age of 77.9 years (range 70–89) underwent RT. In the CCRT group, 14 patients (70%) completed CCRT consisting of radiotherapy and 5 courses of cisplatin plus 5-fluorouracil including patients requiring a dose reduction of chemotherapy. The median overall survival (OS) in the CCRT and RT groups was 66.9 and 60.1 months, respectively (p = 0.156). The most common grade 3/4 acute toxicity was hyponatremia (35.0%), followed by neutropenia (15.0%) and diarrhea (10.0%) in the CCRT group, while this was anemia (17.2%) followed by radiation enteritis (10.3%) in the RT group. Conclusions CCRT was well tolerated in elderly patients with cervical cancer. Careful attention should be paid to the different characteristics of treatment-related toxicities in this group compared with younger patients.


Oncology Reports | 2016

PRIMA-1MET induces apoptosis through accumulation of intracellular reactive oxygen species irrespective of p53 status and chemo-sensitivity in epithelial ovarian cancer cells

Nobuhisa Yoshikawa; Hiroaki Kajiyama; Kae Nakamura; Fumi Utsumi; Kaoru Niimi; Hiroko Mitsui; Ryuichiro Sekiya; S. Suzuki; Kiyosumi Shibata; David F. Callen; Fumitaka Kikkawa

There is an intensive need for the development of novel drugs for the treatment of epithelial ovarian cancer (EOC), the most lethal gynecologic malignancy due to the high recurrence rate. TP53 mutation is a common event in EOC, particularly in high-grade serous ovarian cancer, where it occurs in more than 90% of cases. Recently, PRIMA-1 and PRIMA-1MET (p53 reactivation and induction of massive apoptosis and its methylated form) were shown to have an antitumor effect on several types of cancer. Despite that PRIMA-1MET is the first compound evaluated in clinical trials, the antitumor effects of PRIMA-1MET on EOC remain unclear. In this study, we investigated the therapeutic potential of PRIMA-1MET for the treatment of EOC cells. PRIMA-1MET treatment of EOC cell lines (n=13) resulted in rapid apoptosis at various concentrations (24 h IC50 2.6–20.1 µM). The apoptotic response was independent of the p53 status and chemo-sensitivity. PRIMA-1MET treatment increased intracellular reactive oxygen species (ROS), and PRIMA-1MET-induced apoptosis was rescued by an ROS scavenger. Furthermore, RNA expression analysis revealed that the mechanism of action of PRIMA-1MET may be due to inhibition of antioxidant enzymes, such as Prx3 and GPx-1. In conclusion, our results suggest that PRIMA-1MET represents a novel therapeutic strategy for the treatment of ovarian cancer irrespective of p53 status and chemo-sensitivity.


European Journal of Obstetrics & Gynecology and Reproductive Biology | 2014

Oncologic outcome after recurrence in patients with stage I epithelial ovarian cancer: are clear-cell and mucinous histological types a different entities?

Hiroaki Kajiyama; Mika Mizuno; Kiyosumi Shibata; Tomokazu Umezu; S. Suzuki; Eiko Yamamoto; Hiroko Mitsui; Ryuichiro Sekiya; Kaoru Niimi; Michiyasu Kawai; Tetsuro Nagasaka; Fumitaka Kikkawa

OBJECTIVES This study was conducted to estimate the oncologic outcome of stage I epithelial ovarian carcinoma (EOC) patients after recurrence. STUDY DESIGN After central pathological review and searching of the medical records of multi-institutions, a total of 103 relapsed patients with stage I EOC were analyzed. The major endpoint was postrecurrence survival (PRS). RESULTS The median follow-up for surviving patients was 57.5 (5.7-242.0) months. The median age was 52 (14-89). Among the patients, 19 (18.4%) had FIGO IA disease, and 4 (3.9%) and 80 (77.7%) had IB and IC disease, respectively. Regarding the histological type, the clear-cell type was the most frequently observed (N=42: 40.8%). The 3/5-year overall and PRS rates of all patients were 63.7/47.9 and 38.2/24.0%, respectively. The 5-year PRS rates of patients with serous, endometrioid, clear-cell, and mucinous tumors were 44.9, 35.0, 19.8, and 0%, respectively. On stratifying by the histological type, the overall and postrecurrence survival rates of patients with the mucinous/clear-cell types were significantly poorer than in those with the non-mucinous/clear-cell types (OS: P=0.0253, PRS: P=0.0016). In multivariate analyses, the FIGO stage (IA/IB vs. IC) and histological type (clear-cell/mucinous vs. non- clear-cell/mucinous) retained their significance as prognostic factors of a poorer PRS {stage IC (vs. IA/B) HR 2.176 (95% CI: 1.059-4.470), P=0.0343: clear-cell/mucinous (vs. non- clear-cell/mucinous): HR: 2.486(95% CI: 1.416-4.364), P=0.0015). CONCLUSIONS Even if at stage I, once patients with a mucinous/clear-cell histology experience recurrence, subsequent survival is extremely poor.


Journal of Obstetrics and Gynaecology Research | 2017

Clinical significance and predicting indicators of post‐cancer‐treatment survival in terminally ill patients with ovarian cancer

Fumi Utsumi; Hiroaki Kajiyama; Kaoru Niimi; Ryuichiro Sekiya; Jun Sakata; S. Suzuki; Kiyosumi Shibata; Mika Mizuno; Fumitaka Kikkawa

Women with ovarian cancer (OC) often experience relapse and receive further repetitive chemotherapy. The objective of this study was to overview the remaining survival time after the final chemotherapy and to examine influential clinicopathologic indicators in those patients.


Oncotarget | 2018

Fertility-sparing surgery of malignant transformation arising from mature cystic teratoma of the ovary

Nobuhisa Yoshikawa; Toshiya Teshigawara; Yoshiki Ikeda; Kimihiro Nishino; Jun Sakata; Fumi Utsumi; Kaoru Niimi; Ryuichiro Sekiya; S. Suzuki; Michiyasu Kawai; Kiyosumi Shibata; Fumitaka Kikkawa; Hiroaki Kajiyama

Background The purpose of this study was to evaluate the long-term clinical outcome of young women with malignant transformation arising from mature cystic teratoma of the ovary (MT-MCT) by comparing radical surgery and fertility-sparing surgery (FSS). Patients and methods All patients treated with radical surgery or FSS for MT-MCT in multiple institutions were registered in this analysis. Univariate and multivariate analyses were performed to evaluate clinical outcome, including overall survival (OS) and disease-free survival (DFS). Results From 1986 to 2016, 62 patients with MT-MCT were treated in our group. The median follow-up period was 38.0 (2.0-227.9) months, and the median age was 54 (17-82) years old. Multivariate analysis revealed that only advanced stage was significantly correlated with poorer prognosis of patients [hazard ratio (HR) for death: 6.58, 95% confidence interval (CI): 1.82–24.78, P = 0.0048; HR for recurrence: 5.59, 95% CI: 1.52–21.83, P = 0.01]. Of a total of 13 women with stage I-II disease at less than 45 years old, 7 were treated with FSS, and there was no recurrence except for in one woman with stage II MT-MCT. There was no significant difference in long-term oncological outcome between radical surgery and FSS. Conclusion FSS may be indicated for patients with stage I MT-MCT, who hope to preserve fertility, as no relapse was found after FSS.

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