Estrogen receptor-mediated miR-486-5p regulation of OLFM4 expression in ovarian cancer

Estrogen signaling influences the development and progression of ovarian tumors, but the underlying mechanisms are not well understood. In a previous study we demonstrated that impairment of estrogen receptor alpha (ERα)-mediated olfactomedin 4 (OLFM4) expression promotes the malignant progression of endometrioid adenocarcinoma, and we identified OLFM4 as a potential target of miR-486-5p. In this study we investigated the role of OLFM4 in ovarian serous adenocarcinoma. Ovarian serous adenocarcinoma tissues had reduced OLFM4 expression. Expression of OLFM4 was positively correlated with ERα expression, and estrogen (E2) treatment in ovarian cancer cells induced OLFM4 expression in an ERα-dependent manner. In contrast to ERα, miR-486-5p levels were inversely correlated with OLFM4 expression in ovarian serous adenocarcinoma. Ovarian cancer cells transfected with miR-486-5p mimics showed decreased OLFM4 mRNA expression, and ovarian cancer cells treated with E2 showed reduced cellular miR-486-5p levels. OLFM4 knockdown enhanced proliferation, migration, and invasion by ovarian cancer cells. Low expression of OLFM4 was also associated with high tumor FIGO stage and poor tumor differentiation. These results suggest OLFM4 is downregulated by miR-486-5p, which contributes to ovarian cancer tumorigenesis. Conversely, estrogen receptor signaling downregulates miR-486-5p and upregulates OLFM4 expression, slowing the development and progression of ovarian cancer.