Comparative genotoxicity investigation using comet and gammaH2AX assays for screening of genotoxicants in HepG2 human hepatoma cells

As public interest in safety has increased the toxicity evaluation of chemicals become more important. In this study, the DNA-damaging effect of genotoxicants was examined in HepG2 cell line originated from human hepatocellular carcinoma by widely used genotoxicity assays: the comet assay and gammaH2AX immunostaining. Four different direct/indirect genotoxicants were tested in dose-/time-dependent manner. The comet assay and the gammaH2AX immunostaining enables detection of DNA damages in the form of DNA strand breaks with different sensitivity. Therefore, the combination of comet assay and gammaH2AX immunostaining will be complementary tool for evaluation of various forms and degree of DNA damage. Our result also suggested that HepG2 cells could be a suitable model for assessing the genotoxicity of various mutagens and for determining the lowest genotoxic concentration. Further analysis using a larger number of chemicals is warranted to determine the sensitivity and the specificity of HepG2 with in vitro genotoxicity test.