PNMA5 knockdown suppresses the proliferation, invasion, and metastasis of epithelial ovarian cancer cells.

BACKGROUND: Ovarian cancer is a severe gynecological malignancy. Paraneoplastic Ma antigen 5 (PNMA5) is a confirmed tumor onconeural antigen, which has been screened as a female fertility factor. PNMA5 overexpression might serve as a marker of poor prognosis in colon cancer. Our earlier study showed that PNMA5 was essential for meiosis in mouse oocytes. In this study, we investigate the role and probable mechanism of PNMA5 in the occurrence and development of epithelial ovarian cancer (EOC). METHODS: Immunochemistry and western blot analyses were used to verify PNMA5 overexpression in clinical EOC tissues and EOC cell line HO8910. A specific siRNA was used to reduce PNMA5 levels, and several proliferation and migration-related indexes were assessed. We also examined mitochondria, microfilaments, and several essential kinases. RESULTS: We found that the expression of PNMA5 in EOC tissues was significantly higher than that in benign ovarian tumors and healthy normal ovarian tissues and that this was strictly related to the FIGO stage and histological grade. PNMA5 expression in ovarian cancer cell line HO8910 was higher than that in the normal healthy ovarian cell line Moody. PNMA5 knockdown in HO8910 cells not only inhibited the proliferation, migration, invasion, cell cycle, and F-actin polymerization of HO8910 cells but also promoted early apoptosis and led to abnormal distribution and accumulation of mitochondria. PNMA5 phosphorylation was found to be positively regulated by Src activity, and PNMA5 phosphorylation promoted the downstream glycogen synthase kinase-3ß (GSK-3ß) signaling pathway. CONCLUSIONS: PNMA5 plays a pivotal role in the occurrence and development of EOC and is a potential marker of this disease.