Proteomic analysis of cellular responses to different concentrations of anti-benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide in human amniotic epithelial FL cells.

Benzo(a)pyrene is an ubiquitous environmental carcinogen produced during incomplete combustion of organic substances, and anti-benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), is the most carcinogenic form of its ultimate metabolites. The goal of this study was to examine the response of human amniotic epithelial FL cells to increasing concentrations of BPDE and to find potential biomarkers involved in this cellular response. Human amniotic epithelial FL cells were incubated with 0.005, 0.05, and 0.5 microM BPDE to obtain protein extracts which were resolved by two-dimensional electrophoresis (2-DE) and visualized by silver staining. More than 60 protein spots significantly changed after BPDE exposure. Among these, 2 spots were detected only in the exposed group, and 36 spots were up-regulated, while 27 spots were down-regulated. These altered spots were excised from the gels and analyzed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS). The analysis led to the identification of 46 proteins affected by BPDE. These proteins were involved in regulation of transcription, cell cycle, cell proliferation, transport, signal transduction, metabolism, and so forth. However, no single protein changed in a dose-dependent manner in all three concentrations. Therefore, the changes of proteomic profiles cannot be considered as only an amplification of low-dose response in the case of high-dose exposure and the cellular responses to different doses of DNA damaging agent may be quite different. These results will aid our understanding of the mechanism of BPDE-induced cell response and provide the possibility of the establishment of potential biomarkers.