Bisphenol A Induces Leptin Receptor Expression, Creating More Binding Sites for Leptin, and Activates the JAK/Stat, MAPK/ERK and PI3K/Akt Signalling Pathways in Human Ovarian Cancer Cell

We previously demonstrated that bisphenol A (BPA) promotes proliferation in OVCAR-3 human ovarian cancer cells. This study was designed to investigate the effects of BPA on leptin expression and activity in ovarian cancer. Real-time PCR, Western blot analysis and ELISA assays were used to quantify leptin receptor expression and leptin gene and protein expression after treatment with BPA at doses of 0.2, 2, 8 and 20ng/ml. Our data reveal leptin receptor expression but an absence of leptin gene and protein expression in OVCAR-3 cells. At doses of 8 and 20ng/ml, BPA had stimulatory effects on leptin receptor gene and protein expression. Leptin and BPA alone stimulated cell proliferation but BPA did not potentiate leptin activity. Similarly to leptin, but with different kinetics and duration, BPA induced phosphorylation of Stat3, ERK1/2 and Akt. In co-treatment experiments, the timing of protein phosphorylation represented an additive effect of BPA and leptin treatment. In conclusion, taking into consideration limitation of in vitro study, whether BPA by creating more binding sites for leptin and extending the time of leptin-induced Stat3, ERK1/2 and Akt phosphorylation, can potentiated leptin action in cancer cells, require confirmation by in vivo study.