Published papers

Differentiation of placental trophoblast stem (TS) cells to trophoblast giant (TG) cells is accompanied by transition from a mitotic cell cycle to an endocycle. Here, we report that Cdh1, a regulator of the anaphase-promoting complex/cyclosome (APC/C), negatively regulates mitotic entry upon the mitotic/endocycle transition. TS cells derived from homozygous Cdh1 gene-trapped (Cdh1GT/GT) murine embryos accumulated mitotic cyclins and precociously entered mitosis after induction of TS cell differentiation, indicating that Cdh1 is required for the switch from mitosis to the endocycle. Furthermore, the Cdh1GT/GT TS cells and placenta showed aberrant expression of placental differentiation markers. These data highlight an important role of Cdh1 in the G2/M transition during placental differentiation.

Purpose: In this study, we compared second-line chemotherapy effects of nodal metastases with other metastases sites. Methods: The medical records of 44 women with recurrent ovarian cancer who received second-line chemotherapy were retrospectively reviewed. Results: Median age at the time of second-line chemotherapy was 55 years (range: 31-74). Recurrent sites were as follows: 29 patients had a solitary site (abdominal cavity: 8; lymph node: 3; pelvic cavity: 10; liver: 4; lung: 4) and 15 patients had multiple sites In total, the response rate was 30% (CR: 8, PR: 5). The response rate in sensitive cases was higher than in refractory/resistant cases (50% vs 5% p = 0.002). However, age, chemotherapy regimen, histologic type and number of diseases were not related with chemotherapy effect. In all diseases, response rate tended to be higher in lymph node disease than in the others (44% vs 27%). In both sensitive and refractory/resistant cases, response rate tended to be higher in lymph node disease. Conclusion: The response rate for lymph node diseases tended to be relatively high. Further study analyzing survival will be required to conclude the chemotherapy effect.

Epithelioid sarcoma of the vulva is an extremely rare and aggressive tumor. This tumor most commonly occurs on the labia majora in women of reproductive age. The molecular pathogenesis remains largely unknown. Only 20 cases of vulvar epithelioid sarcoma have been reported to date and more than half have had poor outcomes. We report a successfully treated case of vulvar epithelioid sarcoma in a 33-year-old woman. We performed a radical vulvectomy with flap reconstruction. Three years after surgery, the patient remains well, showing no evidence of recurrence. Early tissue diagnosis of vulvar epithelioid sarcoma is essential because this tumor can be clinically misdiagnosed as a benign lesion. Gynecologists should be aware of this rare tumor variant and carefully plan the treatment.

Various key cell cycle components, especially G0/G1 regulators, have effects not only on cell proliferation but also on cell differentiation. Cdh1, one of the co-activators that maintain anaphase-promoting complex/cyclosome activity, plays a crucial role in the mitotic phase, but has recently been identified as a G0/G1 regulator, suggesting that the role of Cdh1 in cell differentiation. Here, we generated Cdh1 conditional gene-trap mice to examine Cdh1 functions in adult tissues by overcoming the embryonic lethality of Cdh1 homozygous gene-trap mice. We focused on the hematopoietic system and found that Cdh1-deficient mice exhibited a general decrease in mature lineage progenitor cells and a significant increase in short-term hematopoietic stem cells. This phenomenon became conspicuous by irradiation shortly after Cdh1 downregulation, suggesting that Cdh1 regulates the pool sizes of the hematopoietic stem cells and mature lineage progenitor cells by protecting cells from genotoxic stress. We also found that the irradiation-induced G2/M checkpoint was defective in Cdh1-deficient BM cells, causing the loss of stem/progenitor cells. This is the first report revealing Cdh1 function in adult hematopoiesis and showing a role of Cdh1 in a G2/M checkpoint regulation in vivo.

Cdh1 is an activator of the anaphase-promoting complex/cyclosome and contributes to mitotic exit and G1 maintenance by targeting cell cycle proteins for degradation. However, Cdh1 is expressed and active in postmitotic or quiescent cells, suggesting that it has functions other than cell cycle control. Here, we found that homozygous Cdh1 gene-trapped (Cdh1 GT/GT) mouse embryonic fibroblasts (MEFs) and Cdh1-depleted HeLa cells reduced stress fiber formation significantly. The GTP-bound active Rho protein was apparently decreased in the Cdh1-depleted cells. The p190 protein, a major GTPase-activating protein for Rho, accumulated both in Cdh1 GT/GT MEFs and in Cdh1-knockdown HeLa cells. Cdh1 formed a physical complex with p190 and stimulated the efficient ubiquitination of p190, both in in vitro and in vivo. The motility of Cdh1-depleted HeLa cells was impaired; however, codepletion of p190 rescued the migration activity of these cells. Moreover, Cdh1GT/GT embryos exhibited phenotypes similar to those observed for Rho-associated kinase I and II knockout mice: eyelid closure delay and disruptive architecture with frequent thrombus formation in the placental labyrinth layer, respectively. Furthermore, the p190 protein accumulated in the Cdh1GT/GT embryonic tissues. Our data revealed a novel function for Cdh1 as a regulator of Rho and provided insights into the role of Cdh1 in cell cytoskeleton organization and cell motility.

Objectives: Endometrioid type adenocarcinoma sometimes occupies both endometrium and ovary and in some cases the origin cannot be determined. Study design: In this study, we established a formula to distinguish ovarian endometrioid cancer (EOC) from endometrioid type endometrial cancer (EEC), based on our previous report of cyclin and KI67 expression pattern by immunohistochemistry of 36 EECc and 37 OECc by the logistic regression. We calculated the diagnostic accuracy using 92 test samples retrospectively and finally could diagnose the origin of 16 cases in whom endometrioid type adenocarcinoma arose in both ovary and endometrium and could be determined by Scully's criteria, and 15 cases in whom endometrioid type adenocarcinoma arose in both ovary and endometrium and Scully's criteria were not usuful retrospectively. Results: The estimated formula is as follows: Logit(Prob(EOC)) = -1.1437 - 0.0853 CNA + 0.0423 CNB + 0.173 CND1 + 0.0129 CNE + 0.0224 CNF + 0.0508 KI67, where Prob(EOC) is the probability that a clinical sample is EOC. If Prob(EOC) is larger than 0.5, the diagnosis is ovarian cancer; if less than 0.5 it is endometrial cancer. Finally, using the formula, 37 of 48 EECs (77.1%) and 33 of 44 EOCs (75.0%) were correctly classified, with an accuracy of 76.1% (p < 0.0001), retrospectively. In 12 of the 16 cases (75%) who could be determined by Scully's criteria, the origin determined by Scully's criteria was concordant with the origin determined by the formula retrospectively. In the other 15 cases, 12 cases were judged as ovary/ovary, 2 cases were judged as uterus/uterus and 1 case was judged as uterus/ovary. Conclusion: The formula we established was thought to be useful to distinguish the origin of the cases in whom endometrioid type adenocarcinoma arises in both ovary and endometrium.

© 2019 American Association for Cancer Research Inc. All rights reserved. The role of phospholipid signaling in ovarian cancer is poorly understood. Sphingosine-1-phosphate (S1P) is a bioactive metabolite of sphingosine that has been associated with tumor progression through enhanced cell proliferation and motility. Similarly, sphingosine kinases (SPHK), which catalyze the formation of S1P and thus regulate the sphingolipid rheostat, have been reported to promote tumor growth in a variety of cancers. The findings reported here show that exogenous S1P or overexpression of SPHK1 increased proliferation, migration, invasion, and stem-like phenotypes in ovarian cancer cell lines. Likewise, overexpression of SPHK1 markedly enhanced tumor growth in a xenograft model of ovarian cancer, which was associated with elevation of key markers of proliferation and stemness. The diabetes drug, metformin, has been shown to have anticancer effects. Here, we found that ovarian cancer patients taking metformin had significantly reduced serum S1P levels, a finding that was recapitulated when ovarian cancer cells were treated with metformin and analyzed by lipidomics. These findings suggested that in c

Cellular differentiation is regulated through activation and repression of defined transcription factors. A hallmark of differentiation is a pronounced change in cell shape, which is determined by dynamics of the actin cytoskeleton. Here we show that regulation of the transcriptional coactivator MKL1 (megakaryoblastic leukemia 1) by actin cytoskeleton dynamics drives adipocyte differentiation mediated by peroxisome proliferator-activated receptor γ (PPARγ), a master transcriptional regulator of adipogenesis. Induction of adipocyte differentiation results in disruption of actin stress fibres through downregulation of RhoA-ROCK signalling. The consequent rapid increase in monomeric G-actin leads to the interaction of G-actin with MKL1, which prevents nuclear translocation of MKL1 and allows expression of PPARγ followed by adipogenic differentiation. Moreover, we found that MKL1 and PPARγ act in a mutually antagonistic manner in the adipocytic differentiation programme. Our findings thus provide new mechanistic insight into the relation between the dynamics of cell shape and transcriptional regulation during cellular differentiation.

Purpose: The standard regimen for platinum-resistant/refractory recurrent epithelial ovarian cancer (EOC) remains to be determined. In this study, we retrospectively compared the effect of irinotecan (CPT-11) and pegylated liposomal doxorubicin (PLD) in the treatment of platinum-resistant recurrent EOC. Methods: Thirty patients who received salvage chemotherapy with CPT-11 or PLD were included in the study. CPT-11 (100 mg/m 2) was administered intravenously on days 1, 8 and 15 every four weeks. PLD (50 mg/m 2) was administered on day 1 every four weeks. Treatment was repeated, provided that no disease progression or intolerable toxicity occurred. Results: Response rate in the CPT-11 group and PLD group showed no difference at 26.7% (p = 0.66) in both, while non-PD rate was 73.3% vs 33.3% (p < 0.05), respectively. Progression-free survival after CPT-11 treatment and PLD treatment was 28.4 weeks and 16.8 weeks (p = 0.07), respectively. Hand-foot syndrome and mucositis were more common in the PLD group than in the CPT-11 group (p < 0.05). Conclusions: The results indicate that CPT-11 is a promising drug for the treatment of platinum-resistant recurrent EOC.

Background: Endometrial cancer (EC) is the most common cancer of the female genital tract. However, no screening method for EC has been established yet. In this study, we evaluated the cell-free DNA in EC. Methods: Fifteen healthy individuals, 9 with benign gynecologic diseases, and 53 with ECs were included in this study. Alu sequences in free DNA fragments were used as surrogate markers, and cell-free DNA density was measured by quantitative real-time polymerase chain reaction. Results: The cell-free DNA levels in ECs tended to be higher than in benign condition (healthy individuals + benign gynecologic diseases, n = 24; P = 0.095). There was no significant difference in cell-free DNA among stage or histological grade of EC, and no significant change in cell-free DNA before and after operation (P = 0.25): Moreover, in 19 ECs, cell-free DNA decreased after operation, however, in 6 ECs, cell-free DNA did not decrease. Three ECs recurred, and cell-free DNA did not decrease in these cases. Conclusions: Measurement of cell-free DNA is not useful for EC screening; however, the change of cell-free DNA in a patient may be a prognostic biomarker of EC.

The aim of this study was to examine the relation between cofilin 1 expression and progression-free survival in advanced epithelial ovarian cancer. We performed quantitative reverse transcriptase polymerase chain reaction and immunohistochemical analysis in 78 patients with advanced epithelial ovarian cancer (excluding those with mucinous and clear-cell types). All patients received the standard therapy, including staging laparotomy and adjuvant chemotherapy consisting of carboplatin and paclitaxel. Of 78 samples, RNA from 62 samples was available for reverse transcriptase polymerase chain reaction analysis. We defined cofilin 1 high expression as relative gene expression equal to or higher than the median and low expression as gene expression lower than median. The progression-free survival was longer in cofilin 1 low-expression cases than in high-expression cases (P = .039). Multivariate analysis demonstrated that stage and cofilin 1 expression were significant predictors of progression-free survival. Of the 78 samples, 54 were appropriate for immunohistochemical study. In 35 of those 54 cases, cofilin 1 protein expression was detected. The progression-free survival was longer in cofilin 1 protein-negative cases than in protein-positive cases (P = .042). Expression of cofilin 1 may predict the progression-free survival of patients with advanced epithelial ovarian cancer receiving standard therapy.

Objectives: Incidence of lymph node metastasis is relatively high even in early-stage epithelial ovarian cancers (EOC). Lymphadenectomy is important in the surgical treatment of EOC; however, the exact role of lymphadenectomy in the management of EOC remains unclear. In this study, we evaluated lymph node metastasis in stages I and II EOC patients. Patients and Methods: Seventy-nine patients with stage I/II EOC underwent initial surgery, and 68 patients received adjuvant platinum and taxane chemotherapy after surgery at Keio University Hospital. The patients were evaluated with respect to age at diagnosis, clinical stage, histology, histological grade, and tumor laterality. Results: Of the 79 patients, 10 (12.7%) had lymph node metastasis. Of these, 4 (5.1%) had lymph node metastasis in paraaortic lymph node (PAN) only, 1 (1.3%) in pelvic lymph node (PLN) only, and 5 (6.3%) in both PAN and PLN. The incidence of serous-type lymph node metastasis in PAN, PAN + PLN, and total was higher than nonserous type (25% vs 1.5%, P < 0.0001;25% vs 3.0%, P = 0.001; 50% vs 5.9%, P < 0.0001). However, there was no significant difference between lymph node status and T factor or histological grade. In 78% of patients (7/9), metastases in contralateral lymph nodes were present (contralateral, 2; bilateral, 5). There was no significant difference in progression-free survival between node-positive and node-negative groups (P = 0.47). Conclusions: Based on diagnostic value, the result suggests that the role of lymphadenectomy might differ by histological type, as its therapeutic effect might be unclear. A multicenter analysis is essential for confirmation.

AIM: There is poor evidence regarding effective treatment for recurrent endometrial cancer. We treated patients with recurrent endometrial cancer with docetaxel-cisplatin (DP) therapy as second-line or third-line chemotherapy. We aimed to evaluate the feasibility and efficacy of DP therapy for patients with recurrent endometrial cancer.PATIENT AND METHODS: We included 26 patients diagnosed with recurrent endometrial cancer, who underwent DP chemotherapy at our Institution. Docetaxel at 70 mg/m(2)and cisplatin at 60 mg/m(2)were administered by intravenous injection every 3 weeks. We retrospectively analyzed the clinicopathological factors associated with the response rate (RR) and prognosis. We also analyzed the adverse effects of DP therapy.RESULTS: Median follow-up was 33.8 months and the median number of therapy cycles was six. Grade 3 or 4 adverse effects included leukopenia (66%), neutropenia (81%), anemia (9%), diarrhea (12%), general fatigue (12%), liver dysfunction (4%), peripheral neuropathy (4%), and hyponatremia (4%). RR was 58% and the median progression-free survival (PFS) was 7.5 months. The group with a treatment-free interval of 6 months or more tended to have better PFS than that with less than 6 months (p=0.01). The group with a platinum-free interval of 6 months or more had significantly better PFS than that with less than 6 months (p=0.09). Although the history of taxane usage was not relevant to prognosis, a taxane-free interval of 12 months or more was associated with a tendency for better PFS (p=0.06).CONCLUSION: DP therapy was fully feasible and demonstrated efficacy for patients with recurrent endometrial cancer.

© 2020. Asian Society of Gynecologic Oncology, Korean Society of Gynecologic Oncology. Objective: To assess the effectiveness of lymphadenectomy at primary debulking surgery (PDS) on the survival of patients with epithelial ovarian cancer (EOC). Methods: We searched PubMed, Ichushi, and the Cochrane Library. Randomized controlled trials (RCTs) and retrospective cohort studies comparing survival of women with EOC undergoing lymphadenectomy at PDS with that of women without lymphadenectomy were included. We performed a meta-analysis of overall survival (OS), progression-free survival (PFS), and adverse events. Results: For advanced-stage EOC, 2 RCTs including 1,074 women and 7 cohort studies comprising 3,161 women were evaluated. Meta-analysis revealed that lymphadenectomy was associated with improved OS (hazard ratio [HR]=0.80; 95% confidence interval [CI]=0.70– 0.90). However, meta-analysis of 2 RCTs revealed no significant difference in OS between the lymphadenectomy and no-lymphadenectomy groups (OS: HR=1.02; 95% CI=0.85–1.22). For early-stage EOC, 1 RCT comprising 268 women and 4 cohort studies comprising 14,228 women were evaluated. Meta-analysis showed that lymphadenectomy was associated with improved OS (HR=0.75; 95% CI=0.68–0.82). A RCT of early-stage EOC reported that lymphadenectomy was not associated with improved OS (HR=0.85; 95% CI=0.49–1.47). Surgery-related deaths were similar in both groups (risk ratio [RR]=1.00; 95% CI=0.99–1.01); however, blood transfusion was required less frequently in the no-lymphadenectomy group (RR=0.74; 95% CI=0.63–0.86). Conclusions: Meta-analysis of RCTs and observational studies suggest that lymphadenectomy was associated with improved OS in advanced-and early-stage EOC. However, results from RCTs demonstrate that lymphadenectomy was not associated with improved OS in advanced-and early-stage EOC.

The use of primary patient-derived organoids for drug sensitivity and resistance testing could play an important role in precision cancer medicine. We developed expandable ovarian cancer organoids in<3 weeks; these organoids captured the characteristics of histological cancer subtypes and replicated the mutational landscape of the primary tumours. Seven pairs of organoids (3 high-grade serous, 1 clear cell, 3 endometrioid) and original tumours shared 59.5% (36.1-73.1%) of the variants identified. Copy number variations were also similar among organoids and primary tumours. The organoid that harboured the BRCA1 pathogenic variant (p.L63*) showed a higher sensitivity to PARP inhibitor, olaparib, as well as to platinum drugs compared to the other organoids, whereas an organoid derived from clear cell ovarian cancer was resistant to conventional drugs for ovarian cancer, namely platinum drugs, paclitaxel, and olaparib. The overall success rate of primary organoid culture, including those of various histological subtypes, was 80% (28/35). Our data show that patient-derived organoids are suitable physiological ex vivo cancer models that can be used to screen effective personalised ovarian cancer drugs.

© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com. BACKGROUND: Risk-reducing salpingo-oophorectomy is performed for the primary prevention of ovarian cancer in patients with hereditary breast-ovarian cancer syndrome. We performed risk-reducing salpingo-oophorectomy for the first time in Japan in 2008, and we experienced 20 cases of risk-reducing salpingo-oophorectomy through 2019. In the past, the use of risk-reducing salpingo-oophorectomy in Japan was restricted because it was not covered by a Japanese National Health Insurance. Since April 2020, risk-reducing salpingo-oophorectomy has been covered by insurance for patients with breast-ovarian cancer syndrome and pre-existing breast cancer, and this surgery is expected to become more widely implemented in Japan. METHODS: To contribute to the widespread use of risk-reducing salpingo-oophorectomy in the future, we retrospectively reviewed 20 cases of risk-reducing salpingo-oophorectomy at our hospital cohort study to clarify the issues in its implementation. RESULTS: The variant genes for which risk-reducing salpingo-oophorectomy was indicated were BRCA1 and BRCA2 in 13 (65%) and 7 patients (35%), respectively. The median age at which risk-reducing salpingo-oophorectomy was performed was 49 years (range, 38-58), 13 patients (65%) had gone through menopause, and 16 patients (80%) had a history of breast cancer. Of the five patients (25%) with vasomotor symptoms, four received Chinese medicine, and only one received hormone replacement therapy. Occult cancer was detected in the removed ovaries in two patients (10%), although no postoperative peritoneal carcinogenesis has been observed to date. CONCLUSIONS: Women who paid for risk-reducing salpingo-oophorectomy out of pocket were older than the recommended age at which the procedure should be performed, and this may explain the higher rate of occult cancers than previously reported. We need to perform risk-reducing salpingo-oophorectomy at the recommended age to ensure that the procedure is effective for primary prevention.

BACKGROUND: This study aimed to investigate the clinical benefit of dose-dense paclitaxel plus carboplatin (TC) with bevacizumab therapy for advanced ovarian, fallopian tube, and primary peritoneal cancer patients in the neoadjuvant setting. METHODS: Ovarian, fallopian tube or primary peritoneal cancer patients with stage III-IV disease received neoadjuvant chemotherapy (NAC) every 3 weeks consisting of paclitaxel (80 mg/m2) on days 1, 8, and 15; carboplatin (AUC 6.0 mg/mL × min.) on day 1; and bevacizumab (15 mg/kg) on day 1. Interval debulking surgery (IDS) was performed after 3 cycles of dose-dense TC-bevacizumab therapy. The primary endpoint was the rate of complete resection by IDS. Secondary endpoints were treatment completion rate, treatment exposure, response rate to NAC, adverse events, and perioperative complications. RESULTS: Twenty-four patients were included in this study. The median age was 55.5 years (37-80 years), and most patients had high-grade serous carcinoma accounted (n = 18). IDS was performed in all patients with complete resection achieved in 75% (95% confidence interval: 57.7-92.3%). The lower limit exceeded the preset threshold rate of 55%. The response rate to NAC was 79%, and serum CA125 levels were in the normal range after NAC in 57% of patients. Grade 4 hematological toxicities and grade 3/4 non-hematological toxicities occurred in 29% and 17% of patients during NAC, respectively. Grade 3/4 perioperative complications were seen in 29% of patients, but no gastrointestinal perforations or treatment-related deaths occurred. CONCLUSIONS: Neoadjuvant dose-dense TC-bevacizumab therapy was well tolerated, and a satisfactory rate of complete resection by IDS was achieved.

Osteosarcoma is a malignant bone tumor in children and adolescents characterized by intrinsic therapeutic resistance. The IGF2 is expressed at elevated levels in osteosarcoma after treatment with chemotherapy, prompting an examination of its functional contributions to resistance. We found that continuous exposure to IGF2 or insulin in the absence of serum created a dormant growth state in osteosarcoma cells that conferred resistance to various chemotherapeutic drugs in vitro. Mechanistic investigations revealed that this dormant state correlated with downregulation of downstream signaling by the IGF1 receptor, heightened cell survival, enhanced autophagy, and the presence of extracellular glutamine. Notably, inhibiting autophagy or depleting glutamine was sufficient to increase chemotherapeutic sensitivity in osteosarcoma xenografts in mice. Clinically, we confirmed that IGF expression levels were elevated in human osteosarcoma specimens from patients who received chemotherapy. Together, our results suggest that activation of IGF or insulin signaling preserves the survival of osteosarcoma cells under chemotherapeutic stress, providing a drug-resistant population that may engender minimal residual disease. Attenuating this survival mechanism may help overcome therapeutic resistance in osteosarcoma.