EFFECTS OF XENOESTROGENIC ENVIRONMENTAL-POLLUTANTS ON THE PROLIFERATION OF A HUMAN BREAST-CANCER CELL-LINE (MCF-7)

A human breast cancer cell line (MCF-7) was used to develop an in vitr o screening assay for the detection of xenoestrogenic environmental po llutants. MCF-7 cells were cultured in DMEM containing 5% fetal bovine serum (FBS). An estrogenic response was defined as an increase in the frequency of proliferating MCF-7 cells, and was measured using a thym idine analog, bromodeoxyuridine, and flow cytometry. Di-2-ethylhexyl p hthalate (DEHP) and 4-n-nonylphenol (4-n-NP) were used as model chemic als. The proliferation rate of S-phase cells after 24 h of exposure to various concentrations of 17 beta-estradiol and to model compounds wa s compared with a positive and a negative control, containing 1 nM 17 beta-estradiol and 0.1% ethanol, respectively. DEHP and 4-n-NP increas ed the frequency of proliferating MCF-7 cells in a dose-dependent mann er. The lowest concentration that significantly increased the prolifer ation of MCF-7 cells was 10 mu M for DEHP and 1 mu M for 4-n-NP. The r esults showed that the assay is accurate and quick to perform. It may prove a valuable tool for screening potential estrogen-mimicking envir onmental pollutants.