Effect of 17-beta-estradiol on doxorubicin cytotoxicity in human breast cancer cell culture.

Pre-treatment with 17-beta-estradiol appeared to improve the cytotoxic efficacy of doxorubicin on MCF-7 but not on ZR-75-1 and EVSA-T human breast cancer cell lines. MCF-7 and ZR-75-1 are both estrogen receptor-positive cell lines: however, only ZR-75-1 showed improved proliferation in the presence of estradiol. On the other hand MCF-7 appeared basically more resistant to doxorubicin compared to the other cell lines. The results indicate that estrogenic pre-treatment is a potential tool for partially overcoming human breast cell resistance to doxorubicin; moreover, they suggest that the mechanism of interaction could be not exclusively related to actual cytokinetics modulation.