Takahiro Koyanagi

Progesterone Enhances Sensitivity of Ovarian Cancer Cells to SN38 Through Inhibition of Topoisomerase I and Inducing Ferroptosis

ABSTRACTBackgroundProgesterone rapidly induces ovarian cancer cell death through non‐genomic actions mediated by the membrane progesterone receptor (mPR).AimsWe investigated the combined effects of progesterone and SN38, an active metabolite of irinotecan, on ovarian cancer cells.Methods and ResultsmPR‐positive and PR‐negative ovarian cancer cell lines were utilized in experiments. Tumor cells were exposed to SN38 or cisplatin for 48 h following exposure to progesterone for 30 min. The viable cell counts were measured using a colorimetric assay and the expression of topoisomerase I (TOPO‐I), the direct target of SN38, was observed with or without exposure to progesterone. Moreover, we investigated the relationship between several types of programmed cell death and the SN38 sensitivity enhancement effect of progesterone using specific cell death inhibitors. The chemosensitivity to SN38 was 8.7‐ to 26.0‐fold higher with the administration of progesterone than that without (p < 0.01), but not to cisplatin in ovarian cancer cells. Progesterone suppressed the expression of TOPO‐I mRNA by less than 50% (p < 0.01). Furthermore, among various programmed cell death inhibitors, only the ferroptosis inhibitor attenuated the progesterone‐induced SN38 chemosensitivity enhancement effect.ConclusionsProgesterone increased sensitivity to SN38 by suppressing TOPO‐I expression and inducing ferroptosis. The combination of progesterone and irinotecan could be a novel treatment modality for ovarian cancer.

Forced Vasohibin‐1 Expression Increases Paclitaxel Sensitivity of Ovarian Cancer by Inhibiting Microtubule Activity

ABSTRACTBackgroundVasohibin‐1 (VASH1), an angiogenic inhibitor, exhibits tubulin carboxypeptidase activity, which is involved in microtubule functions. Paclitaxel, the core chemotherapeutic agent for ovarian cancer chemotherapy, has a point of action on microtubules and may interact with VASH1.AimsTo examine the influence of VASH1 on intracellular tubulin detyrosination status, cyclin B1 expression, and paclitaxel chemosensitivity using VASH1‐overexpressing ovarian cancer cell lines.Methods and ResultsGene‐transfected human ovarian cancer cell lines were subjected to western blot analysis. Western blot analysis of VASH1‐overexpressing ovarian cancer cells revealed upregulated expression of detyrosinated tubulin and cyclin B1 compared with control cells. By WST‐1 assay, paclitaxel chemosensitivity of VASH1‐overexpressing ovarian cancer cells was markedly enhanced compared with that of control cells, whereas there was no significant difference in chemosensitivity to cisplatin. The forced expression of VASH1 enhanced tubulin carboxypeptidase activity and increased cyclin B1 expression, resulting in augmented paclitaxel chemosensitivity in ovarian cancer cells.ConclusionOvarian cancer treatment strategies targeting VASH1 can potentiate the effects of conventional chemotherapy by inhibiting angiogenesis and regulating microtubule activity.

The role of non‐genomic actions of progesterone and its membrane receptor agonist in ovarian cancer cell death

AbstractBackgroundProgesterone therapy is a relatively inexpensive treatment option for endometrial and breast cancers, with few side effects. Two signaling pathways usually mediate the physiological effects of progesterone, namely genomic and non‐genomic actions. Genomic action occurs slowly via the nuclear progesterone receptor (PR), whereas the membrane progesterone receptor (mPR) induces rapid non‐genomic action.AimsWe investigated the effects of progesterone and various PR agonists on ovarian cancer cells.Methods and ResultsPR expression of six serous ovarian cancer cell lines was examined by western blotting, and mPR expression was examined by reverse transcription‐quantitative polymerase chain reaction (RT‐qPCR). PR‐negative and mPR‐positive ovarian cancer cells were exposed to progesterone and seven types of PR agonists (medroxyprogesterone acetate [MPA], dehydroepiandrosterone, dienogest, levonorgestrel, drospirenone, pregnenolone, and allopregnanolone) at 10–400 μM, and viable cell counts after exposure for 30 min were measured using the water‐soluble tetrazolium (WST‐1) assay. Ovarian cancer cell lines were exposed to 100 μM progesterone, and the expression of BAX, a pro‐apoptotic protein, after 1–5 min was examined by western blotting.Western blotting detected no PR expression in the six serous ovarian cancer cell lines. In contrast, RT‐qPCR detected mPR expression in all six serous ovarian cancer cell lines. Progesterone and MPA‐induced cell death in all tested ovarian cancer cell lines in a concentration‐dependent manner, whereas no effect was observed for other PR agonists. Western blotting revealed that pro‐apoptotic protein BAX expression occurred 1 min after exposure to progesterone, suggesting that the cytocidal effects are mediated by rapid non‐genomic action.ConclusionProgesterone and MPA exhibited a rapid cytocidal effect on PR‐negative ovarian cancer cells through non‐genomic action. Progesterone and MPA could be novel adjuvant therapies for ovarian cancer.

Cervical cancer screening efficacy using SurePath , ThinPrep and conventional cytology: A large data set analysis from the Japan Cancer Society

Abstract Objective Over the past decade, liquid‐based cytology has replaced conventional cytology for cervical cancer screening in many countries, including Japan. We aimed to evaluate the efficacy of liquid‐based cytology using a large database and compare two major liquid‐based cytology platforms, SurePath and ThinPrep, to conventional cytology. Methods Cervical cancer screening data were collected from the Japan Cancer Society between 2015 and 2019. The efficacy of liquid‐based and conventional cytology in detecting cervical intraepithelial neoplasia (CIN) was evaluated. Detection rates and positive predictive values were compared using a Poisson regression model. Results We collected data of 3,918,149 participants, including 2,248,202 conventional cytology, 874,807 SurePath and 795,140 ThinPrep smears. The detection rate of CIN2 or more was 1.14 times higher using SurePath than that using conventional cytology (95% confidence interval [CI], 1.09–1.20; p  < 0.001). Contrastingly, the detection rate of CIN2 or more was 0.91 times lower using ThinPrep (95% CI, 0.86–0.96; p  < 0.001). The detection rates of CIN3 or more did not differ significantly between SurePath and conventional cytology (detection rate ratio, 1.04; 95% CI, 0.97–1.12; p  = 0.224). The positive predictive value ratios of CIN2 or more were 0.80 using SurePath (95% CI, 0.76–0.84; p  < 0.001) and 0.83 using ThinPrep (95% CI, 0.79–0.87; p  < 0.001) compared with conventional cytology. Conclusions Liquid‐based cytology, particularly SurePath, was useful for detecting CIN2 or higher in population‐based cervical cancer screening. Further widespread use of liquid‐based cytology methods would lead to efficient detection of cervical precancerous lesions.

Knockout of vasohibin‐2 reduces tubulin carboxypeptidase activity and increases paclitaxel sensitivity in ovarian cancer

AbstractVasohibin‐1 (VASH1) is a VEGF‐inducible endothelium‐derived angiogenesis inhibitor, and vasohibin‐2 (VASH2), its homolog, exhibits proangiogenic activity. VASH2 is expressed by various cancer cells and accelerates tumor angiogenesis and progression. VASH2 was recently shown to exhibit tubulin carboxypeptidase (TCP) activity related to microtubule functions. Paclitaxel (PTX), an effective chemotherapeutic agent that is widely used to treat ovarian cancer, inhibits microtubule depolymerization and may interact with VASH2. We herein established several VASH2 knockout ovarian cancer cell lines using the CRISPR/Cas9 genome editing system to examine the intracellular tubulin detyrosination status and PTX chemosensitivity. The knockout of VASH2 did not affect the proliferation or sphere‐forming activity of ovarian cancer cells in vitro. A Western blot analysis of VASH2 knockout cells revealed the weak expression of detyrosinated tubulin and upregulated expression of cyclin B1. The knockout of VASH2 significantly increased chemosensitivity to PTX, but not to cisplatin in ovarian cancer cell lines. The knockout of VASH2 reduced TCP activity and increased cyclin B1 expression, resulting in increased PTX chemosensitivity in ovarian cancer cells. The inhibition of angiogenesis and regulation of microtubule activity may be achieved in ovarian cancer treatment strategies targeting VASH2.