Optimization of Estrogenic Activity Detection Method Using Human Breast Cancer MCF-7 Cells

We tried to optimize the assay system using human breast cancer MCF-7 cells for detection of estrogenic activity of environmental estrogens. Since fetal bovine serum (FBS) contains various growth factors including estrogen, 100ml of FBS was treated with 5g of activated charcoal to remove estrogen. MCF-7 cells were cultured with RPMI 1640 medium supplemented with FBS or charcoal treated FBS (cFBS), in the presence of 17β estradiol or flavonoids. Then, the cells were trypsinized and cell number was counted using a Coulter Counter. When the cells were cultured in the medium containing 0 to 0.5% FBS, proliferation-stimulating activity of daidzein and genistein was detected most strongly in the medium containing 1% FBS. In the case cFBS-supplemented medium, the effect of flavonoids was detectable, in all cFBS concentrations. The proliferation-stimulating effect of daidzein and genistein was delectable after a 72-hr lag period. In the presence of 1 % FBS or 1 % cFBS, 17 β-estradiol enhanced proliferation of the cells at the concentrations between 10 and 10^<-8> M, while daidzein and genistein enhanced it only at 10^<-8> M. On the other hand, quercetin and luteolin exerted a proliferation-inhibiting activity against MCF-7 cells at the concentrations over 10^<-11> M. These results indicate that estrogenic activity of fiavonoids against MCF-7 cells was detectable in the medium supplemented with 1% FBS or 1 to 5% cFBS. Proliferation-inhibitory activity of quercetin and luteolin suggests that these compounds exert anti-estrogenic and anti-cancer activities