Development of a screening system for DNA damage and repair of potential carcinogens based on dual luciferase assay in human HepG2 cell.

At present, different methods are used for the detection of early biological effects of DNA-damaging agents in environment. Some sensitive testing methods employing DNA damage-inducing genes RNR3, RAD51, RAD54 or growth-arrested and DNA damage-inducible gene 153 (Gadd 153) are used to detect the DNA damage. The host cell reactivation (HCR) assay is a functional assay that is based on the independent transfection of cells with either damaged or undamaged plasmid DNA and allows the identification of the genes responsible for DNA repair-deficient syndromes. In this study, we combined the gadd153-luc test system and HCR assay to measure the DNA damage and DNA repair by dual luciferase assay. We used 16 DNA-damaging agents all of which were detected by a positive dual luciferase reporter test system. The sensitivity of the dual luciferase assay system to detect DNA damage/repair was same as the gadd153-luc test system and/or the HCR assay. Since DNA repair is important to maintain genetic stability, DNA damage and repair have been good biomarkers of early biological effects of DNA-damaging agents. Accordingly, the measurement of DNA repair capacity should be a valued tool in molecular epidemiology studies. The dual luciferase assay described in this study is rapid, convenient, stable and standard.