Effects of Estrogens and Phyto-estrogens on EGF Receptor Expression

摘要

17beta-estradiol treatment up-regulates EGFR mRNA and protein through the action of estrogen receptor (ER)(alpha) on the promoter. We evaluated the activity of natural and synthetic selective ER modulators (SERMs) mediated by ER isoforms (a and beta), through the analysis of the transient expression of the luciferase reporter gene directed by the EGFR gene promoter, in human uterine cervical cancer HeLa cells. E -activated ERbeta presented a lower transcriptional activity compared with ER(alpha). The phytoestrogens, genistein and daidzein, acted as weak agonists via the ERa, but as full agonists when bound to ER(beta). 4OH-tamoxifen exerted a full agonist and antagonist action through ERcc and ERfJ, respectively. In postmenopausal women, local application of soy extract seemed induce maturation of human vaginal squamous epithelium. Our results show that estrogens and SERMs can exert proliferative/differentiative responses depending on the receptor isoform involved and on microenvironmental signalling.