Role of aromatase activation on sodium arsenite-induced proliferation, migration, and invasion of MDA-MB-231 and MDA-MB-453 breast cancer cell lines.

Arsenic is an endocrine disruptor that promotes breast cancer (BCa) development. Estrogen synthesis, through aromatase activation, is essential for BCa promotion and progression through activating the G-coupled estrogen receptor 1 (GPER1), regulating rapid nongenomic effects involved in cell proliferation and migration of BCa cells. Herein, was studied the role of aromatase activation and the GPER1 pathway on sodium arsenite-induced promotion and progression of MDA-MB-231 and MDA-MB-453 BCa cell lines. Our results demonstrated that 0.1 μM of sodium arsenite induces cell proliferation, migration, invasion, and stimulates aromatase activity of BCa cell lines MDA-MB-231, MDA-MB-453, MCF-7, but not in a nontumorigenic breast epithelial cell line (MCF-12A). Using letrozole (an aromatase inhibitor) and G-15 (a GPER1-selective antagonist), we demonstrated that sodium arsenite-induced proliferation and migration is mediated by induction of aromatase enzyme and, at least in part, by GPER1 activation in MDA-MB-231 and MDA-MB-453 cells. Sodium arsenite induced phosphorylation of Src that participated in sodium arsenite-induced aromatase activity, and -cell proliferation of MDA-MB-231 cell line. Overall, data suggests that sodium arsenite induces a positive-feedback loop, resulting in the promotion and progression of BCa cells, through induction of aromatase activity, E2 production, GPER1 stimulation, and Src activation.