Abstract 4540: Follicle-stimulating hormone (FSH) enhances the proliferation of epithelial ovarian cancer cells by activating transient receptor potential channel C3 (TRPC3)

Abstract

Abstract At present, epithelial ovarian cancer is the leading killer among all gynecological malignancies. Despite much research, development of this neoplasm is still not fully understood. The five-year survival rate for this disease still remains about 30%. Recent studies suggest that follicle-stimulating hormone (FSH) may play a major role in ovarian epithelial carcinogenesis. Our group has demonstrated that FSH stimulates the proliferation and invasion of ovarian cancer cells, inhibits apoptosis, and facilitates neovascularization by increasing vascular endothelial growth factor (VEGF) expression. To understand the mechanisms by which FSH stimulates ovarian cancer growth, we have performed gene expression arrays and confirmed changes in protein expression by Western blots. Interestingly, we found that FSH stimulation enhances expression of transient receptor potential channel C3 (TRPC3) at both mRNA and protein levels. Silencing TRPC3 expression by siRNA inhibited the ability of FSH to stimulate proliferation of ovarian cancer cell lines and to block apoptosis. TRPC channels are nonselective cation channels with permeability to Ca2+. Increases in cytosolic free Ca2+ can promote different physiological changes including cell growth, differentiation and death. TRPC3 is one of 7 TRPC family members. Our previous work has shown that TRPC3 contributes to the progression of human ovarian cancer. TRPC3 protein levels in human ovarian cancer specimens were greatly increased relative to those in normal ovarian specimens. Downregulating TRPC3 expression led to reduced proliferation, suppression of epidermal growth factor-induced Ca2+ influx, and decreased growth of xenografts. In this study, we further explored the interaction of FSH-TRPC3. FSH stimulation was associated with upregulation of TRPC3 levels and translocation of TRPC3 from the cytoplasm to cell membrane, facilitating the influx of Ca2+ after treatment with a TRPC3 specific agonist. Knocking down TRPC3 abrogated Akt/PKB phosphorylation by FSH stimulation, leading to decreased expression of down-stream effectors including survivin, HIF1α and VEGF. Our findings indicate that TRPC3 plays a significant role in the tumor-stimulating activity of FSH and could be a potential therapeutic target of ovarian cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4540. doi:10.1158/1538-7445.AM2011-4540