Oxidative modification in nuclear and mitochondrial DNA and its removal in A549 human lung cancer cells exposed to cold atmospheric-pressure plasma

Abstract

Non-thermal atmospheric-pressure plasma has emerged as a useful tool in life science research and medicine. Plasma irradiation generates reactive oxygen and nitrogen species (RONS) that stimulate various cellular responses. In this study, we investigated oxidative damage to nuclear and mitochondrial DNA in A549 human lung cancer cells exposed to a helium atmospheric-pressure plasma jet (APPJ). APPJ irradiation decreased the viability of A549 cells and increased intracellular RONS levels. The formation of 8-oxoguanine (8-oxoG), a representative oxidized form of a DNA base, was observed in nuclear DNA. Pretreatment of A549 cells with an antioxidant reagent prior to APPJ irradiation suppressed the increase in 8-oxoG level. The 8-oxoG level gradually decreased during cell culture, suggesting that 8-oxoG was removed from nuclear DNA after APPJ irradiation. Formation of 8-oxoG was also observed in mitochondrial DNA, indicating the accumulation of RONS in mitochondria.