Zinc finger proteins and other transcription regulators as response proteins in benzo[a]pyrene exposed cells

Proteomic analysis, which combines two-dimensional electrophoresis (2-DE) and mass spectrometry (MS), is an important approach to screen proteins responsive to specific stimuli. Benzo[a]pyrene (B[a]P), a prototype of polycyclic hydrocarbons (PAHs), is a potent procarcinogen generated from the combustion of fossil fuel and cigarette smoke. To further probe the molecular mechanism of mutagenesis and carcinogenesis, and to find potential molecular markers involved in cellular responses to B[a]P exposure, we performed proteomic analysis of whole cellular proteins in human amnion epithelial cells after B[a]P-treatment. Image visualization and statistical analysis indicated that more than 40 proteins showed significant changes following B[a]P-treatment (P < 0.05). Among them, 20 proteins existed only in the control groups, while six were only present in B[a]P-treated cells. In addition, the expression of 10 proteins increased whereas 11 decreased after B[a]P-treatment. These proteins were subjected to in-gel tryptic digestion followed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) analysis. Using peptide mass fingerprinting (PMF) to search the nrNCBI database, we identified 22 proteins. Most of these proteins have unknown functions and have not been previously connected to a response to B[a]P exposure. To further annotate the characteristics of these proteins, GOblet analysis was carried out and results indicated that they were involved in multiple biological processes including regulation of transcription, cell proliferation, cell aging and other processes. However, expression changes were noted in a number of transcription regulators, including eight zinc finger proteins as well as SNF2L1 (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a, member 1), which is closely linked to the chromatin remodeling process. These data may provide new clues to further understand the implication of these proteins in cellular responses to carcinogen exposure as well as the molecular mechanisms of B[a]P-induced mutagenesis and carcinogenesis.