Figure 3
Proposed mechanism by which bisphenol A (BPA) antagonizes cisplatin-induced apoptosis in breast cancer cells. Cisplatin (Pt)
diffuses into the cell and enters the nucleus, where it binds to DNA. The ensuing cell cycle arrest leads to the release of
mitochondrial cytochrome C (Cyt C), activation of caspases and apoptosis. BPA binds either to a membrane receptor or diffuses into the cell and binds to a
cytoplasmic/nuclear receptor. This results in increased expression of the antiapoptotic protein Bcl-2, which blocks Cyt C release and apoptosis. Estradiol (E2) also antagonizes cisplatin-induced apoptosis by activating similar or different mechanisms. Neither the identity of the
receptor(s), which mediate the anticytotoxic actions of BPA/E2, nor the pathway(s) underlying Bcl-2 activation is known.