The Effects of 1‐Nitropyrene on Oxidative DNA Damage and Expression of DNA Repair Enzymes

The Effects of 1‐Nitropyrene on Oxidative DNA Damage and Expression of DNA Repair Enzymes: Yong‐Dae Kim, et al. Department of Preventive Medicine & Medical Research Center, College of Medicine, Chungbuk National University, South Korea —Nitropyrenes (NPs) present in diesel and gasoline emissions are mutagenic and carcinogenic in experimental animals. Nitro‐reduction of 1‐NP causes oxidative stress. It is unclear whether 8‐hydroxydeoxyguanosine (8‐OH‐dG) is produced from 1‐NP and whether it contributes to the carcinogenic activity of 1‐NP. In this study, we measured the level of reactive oxygen species (ROS) in cultured human lung epithelial cells after exposure to 1‐NP and the intracellular level of 8‐OH‐dG and expression level of the 8‐OH‐dG repair enzymes. As results, 1‐NP induced the generation of 8‐OH‐dG via ROS, but 8‐OH‐dG repair enzymes prevented an increase of 8‐OH‐dG formation in cellular DNA of the A549 cell line below 250 µM of 1‐NP. These data suggest that 1‐NP can induce oxidative DNA damage by generation of ROS, which may play a role in the carcinogenesis induced by 1‐NP. These data also suggest that individuals with impaired DNA repair enzymes might be more susceptible to lung cancer induced by 1‐NP.