Effects of sex hormones on folic acid-inhibited proliferation and migration of endothelial cells

Abstract

Background: Pregnant women have been recommended to take folic acid daily for preventing birth defects. However, we previously demonstrated that folic acid can inhibit angiogenesis. We propose that there should have some mechanisms allowing the fetus and the pregnant mother to escape from the folic acid-induced anti-angiogenesis. The present study was designed to study the effect of sex hormones on the folic acid-inhibited proliferation and migration of vascular endothelial cells. Methods: The protein levels and protein-protein interaction were examined by Western blot analysis and immunoprecipitation assay, respectively. The cell number was evaluated using MTT assay and cell migration was examined using wound healing assay. Results: Treatment with folic acid (0.1-10 micromolar) concentration-dependently inhibited endothelial cell proliferation and migration. Co-treatment with folic acid and sex hormones (estradiol, progesterone or androgen receptor agonist) together abolished the folic acid-induced proliferation and migration inhibition in vascular endothelial cells. However, the inhibitory effects caused by sex hormones on folic acid-induced anti-proliferation and anti-migration in endothelial cells were prevented by pre-treatment with their individual receptor antagonists (an estrogen receptor beta (ER beta) antagonist, PHTPP, a progesterone receptor antagonist, Org 31710, or an androgen receptor antagonist, hydroxyflutamide), respectively. Using immunoprecipitation technique, we demonstrated that cSrc, the key molecule involved in folic acid-and sex hormones-regulated endothelial cell proliferation and migration, forms a complex with estrogen receptor, progesterone receptor and androgen receptor in endothelial cells. Conclusions: These data suggest that sex hormones can interfere with the folic acid's action on vascular endothelial cell behaviors.