Estrogenicity of bisphenol A in a human endometrial carcinoma cell line

The ability of bisphenol A (BPA) to affect human estrogen receptor (ER) bin ding, expression of progesterone receptor (PR) mRNA and protein, and cell p roliferation has been measured in the human endometrial cell line,ECC-1. Al though less potent than 17 beta-estradiol, BPA was able to bind to the huma n uterine ER. BPA also induced both mRNA and protein to levels similar to E 2. BPA-mediated PR mRNA induction was antagonized by ICI, suggesting an ER- mediated pathway. Finally, E2 produced a 2-fold increase in cell number, wh ile BPA showed no difference compared with vehicle control. The increase by E2 was inhibited by treatment with the either ICI 182,780 (ICI) or BPA, su ggesting similar binding sites. Although ER binding is similar, E2 affected both proliferation and PR expression, while BPA only affected PR gene expr ession. The results of this study provide evidence that two ER agonists can act differentially in vitro to affect the expression of genes involved in regulating cellular growth and development, though the human risk potential remains to be determined. (C) 1999 Elsevier Science Ireland Ltd. Ail right s reserved.