Electrochemical voltammetry assessment of cellular DNA damage caused by drugs with different mechanisms: A comparative analysis with the γH2AX focus and alkaline comet assays

As industrialization accelerates, there is an increasing need to find a quick, easy, and affordable method to assess the potential DNA damage caused by newly developed chemicals. Electrochemical voltammetry using intracellular purine bases as markers shows promise for detecting DNA damage. However, it is unclear whether drugs with different DNA damage mechanisms will impact purine metabolism in cells and consequently disturb the electrochemical indicators of DNA damage. In this paper, the electrochemical behaviors of HepG2 cells exposed to the direct DNA-damaging agent (MNNG), the indirect DNA-damaging agent (CPT11), and the non-DNA-damaging agent (KCl) were studied. The findings showed that the electrochemical signals of cells increased with the rising concentration of DNA-damaging drugs. A time-dependent effect was observed, with a lower threshold dose for 4 h compared to 1 h. However, the non-DNA-damaging agent did not induce an increase in the cellular electrochemical signal. Despite the higher cytotoxicity of CPT11, MNNG triggered DNA damage at a lower dose, as detected by electrochemical indicators. The results of the electrochemical indicators assessment of DNA damage correlated significantly with those of the γH2AX focus and alkaline comet assays, with r > 0.98 and P < 0.01. Particularly, there was a stronger correlation with the alkaline comet assay. Furthermore, electrochemical voltammetry detected DNA damage at a lower threshold compared to other assessment methods, demonstrating a higher sensitivity to DNA damage. These findings suggest that by using purine bases as markers, electrochemical voltammetry enables precise assessment of DNA damage caused by various mechanisms.