Testosterone and 5α-dihydrotestosterone inhibit in vitro growth of human breast cancer cell lines

Androgens are of biological and clinical importance for the growth and development of breast cancer in women, and the androgen receptor (AR) has been shown to be a predictor of tumor differentiation. In the present study, we investigated the relationship between AR status and testosterone and 5α-dihydrotestosterone (DHT)-dependent proliferation of the human breast carcinoma cell lines MCF-7, T47-D, MDA-MB 435S and BT-20. AR status was studied by means of immunocytochemistry and Western blot analysis. All four cell lines stained positively for AR. Western blot analysis revealed a strong expression of AR in MCF-7, in contrast to BT-20 cells. According to proliferation kinetics, we observed a significant (p ≤ 0.05) dose-dependent inhibition of cell growth by testosterone and DHT treatment in all four cell lines. In the estrogen receptor (ER)-negative cell lines BT-20 and MDA-MB 435S, testosterone was a more potent inhibitor of cell proliferation than DHT (p ≤ 0.05), in contrast to the ER-positive cells lines...