[Effects of environmental estrogens on apoptosis induced by estrogen depletion in T47D cells].

OBJECTIVE: To explore the effects of environmental estrogens (n-4-noniphenol, NP; bisphenol, BisA; and dibutylphthalate, DBP) on apoptosis induced by estrogen depletion in breast cancer T47D cells. METHODS: Human T47D breast cancer cells were grown in DMEM medium containing 10% bovine serum. Four days before adding the test compounds, the cells were washed in phosphate-buffered saline, and the medium was substituted with a phenol red-free DMEM medium containing 5% dextral charcoal-stripped FBS. Respective test compound was added in fresh medium and the control cell received only the vehicle (ethanol). Apoptotic features in T47D cell were analyzed by light microscope that was commonly used to define apoptosis. DNA integrity of T47D cells was examined by agarose gel electrophoresis. Hypodiploid population was detected by flow cytometry. RESULTS: The typical characters of apoptosis in T47D cells were observed after estrogen deletion and then disappeared following exposure to T47D cells at 32 x 10(-7) mol/L Np and 32 x 10(-7) mol/L BisA respectively. Inhibition of apoptosis at 32 x 10(-6) mol/L DBP was not shown in our study. CONCLUSION: N-4-noniphenol and Bisphenol A could inhibit apoptosis induced by estrogen deletion in breast cancer T47D cells. This result suggests that these environmental estrogens might involve in signal transduction connected with apoptosis.