Reporter cell lines to study the estrogenic effects of xenoestrogens

In order to characterize the estrogenic activity of chemicals, we established complementary in vitro recombinant receptor]reporter gene assays in stably transfected MCF-7 and HeLa cells. MCF-7 cells which express the endogenous estrogen receptor a ERa. were stably transfected with only an estrogen-regulated luciferase gene. These cells enable the detection of compounds which bind to ERa or interfere with the induction of ERa mediated gene expression. Furthermore, HeLa cells, which do not express endogenous ERs, were transfected with an ERa or an ERb construct together with an estrogen-regulated luciferase gene, or a chimeric GAL4-ERa receptor and the corresponding luciferase reporter gene. Finally, we tested these four cellular models as tools to check the estrogenic activities of several potential xenoestrogens and to detect estrogenic activity in wastewater sewage treatment effluents. In all of the models, nonylphenol mixture NPm., 4n-nonylphenol 4nNP., 2,49-DDE, 4,49-DDE and wastewater sewage treatment effluent were active, while PCB mixture Aroclor 1254., PCB 77, atrazine and lindane g hexachlorocyclohexane. were inactive. Dioxin partially activates the estrogen receptor in MCF-7 cells while in HeLa-derived cell lines, it decreased the estrogenic-induced expression of luciferase.