Mass spectrometry investigation of DNA adduct formation from bisphenol A quinone metabolite and MCF-7 cell DNA

Bisphenol A (BPA) is a widely used additive in the plastic industry and has been reported to have genotoxicity. A hypothesis that BPA may enhance breast cancer risk through the formation of its metabolic intermediate or DNA adduct has been proposed. In this study, breast cancer cell MCF-7 was cultured and the cellular DNA was extracted from the cells. The adducts of bisphenol A 3,4-quinone (BPAQ) with 2′-deoxyguanosine (dG), calf thymus DNA and MCF-7 cell DNA were investigated. DNA adducts were characterized by using electrospray ionization Orbitrap high-resolution mass spectrometry and tandem mass spectrometry. The BPA-DNA adducts of BPAQ with dG, calf thymus and MCF-7 cell DNA were identified as 3-hydroxy-bisphenol A-N7-guanine (3-OH-BPA-N7Gua). The MS/MS fragmentation pathway of 3-OH-BPA-N7Gua was proposed based on obtained accurate mass data. BPA quinone metabolites can react with MCF-7 cell DNA in vitro. The findings provide evidence that BPA might covalently bind to DNA in MCF-7 cells mediated by quinone metabolites, which may increase our understanding of health risk associated with BPA exposure.