Effects of estradiol plus testosterone on the proliferation and apoptosis of breast cancer cell line MCF-7

Objective: To study the effects of estradiol plus testosterone on the proliferation and apoptosis of breast cancer cell line MCF-7, and to elucidate the possible mechanism. Methods: The growth of MCF-7 cells treated with  estradiol (10-10 mol/L) or testosterone (10-5, 10-7, 10-9 and 10-11 mol/L) alone or in combination for 24, 48 and 72 h was detected by MTT assay. The cell cycle distribution and the apoptosis rate of MCF-7 cells were determined by flow cytometry (FCM). The expression levels of cyclinD1 and androgen receptor (AR) proteins were examined by FCM. Results: The proliferation ability of MCF-7 cells was elevated after treatment with estradiol, and this effect could be inhibited by a higher concentration of testosterone (10-5 mol/L) while improved by a lower concentration of testosterone (10-9 mol/L). After treatment with estradiol plus testosterone (10-5 mol/L) for 48 h, the G1/S phase transition of MCF-7 cells was accelerated, and the apoptosis rate was increased; the expression level of cyclinD1 protein was increased while no change of AR protein expression was observed. Conclusion: Estradiol combined with testosterone of high concentration can inhibit the proliferation of MCF-7 cells and improve the apoptosis. This effect may be associated with the up-regulation of cyclinD1 expression. DOI:10.3781/j.issn.1000-7431.2011.03.002