竹井 裕二

BACKGROUND: Progesterone rapidly induces ovarian cancer cell death through non-genomic actions mediated by the membrane progesterone receptor (mPR). AIMS: We investigated the combined effects of progesterone and SN38, an active metabolite of irinotecan, on ovarian cancer cells. METHODS AND RESULTS: mPR-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. CONCLUSIONS: Progesterone 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.

BACKGROUND: Vasohibin-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. AIMS: To 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 RESULTS: Gene-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. CONCLUSION: Ovarian cancer treatment strategies targeting VASH1 can potentiate the effects of conventional chemotherapy by inhibiting angiogenesis and regulating microtubule activity.

Co-infections with human papillomavirus (HPV) of multiple genotypes mainly occur due to increased sexual activity. To address the prevalence and trend of HPV co-infections in Japan, HPV-type-specific data from Japanese women (n = 8128) aged < 40 years and newly diagnosed with cervical abnormalities at 24 hospitals between 2012 and 2023 were analyzed. These included cervical intraepithelial neoplasia grade 1/2 (CIN1/2, n = 2745), CIN3/adenocarcinoma in situ (AIS) (n = 3953), and invasive cervical cancer (ICC, n = 1430). For women enrolled in this study since 2019, information on sexual behaviors was collected via a self-administered questionnaire. Time-trend analyses by disease category showed significant declines in the prevalence of multiple HPV infections in CIN1/2 (49.1%-38.3%, ptrend = 0.0004), CIN3/AIS (44.7%-31.5%, ptrend = 0.0002), and ICC (26.7%-10.5%, ptrend < 0.0001) during the last decade. When these data were analyzed separately for women aged 20-29 and 30-39 years, similar declining trends were observed in each disease category. Using data from 2111 women for whom information on sexual history was available, the number of sexual partners was strongly associated with increased multiple HPV infections (p < 0.0001). In conclusion, the declining prevalence of HPV co-infections in cervical cancer and its precursors may reflect a decrease in sexual activity among Japanese women of reproductive age.