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The electrochemical detection method of cytotoxicity using intracellular purines as biomarkers has shown great potential for in vitro drug toxicity evaluation. However, no electrochemical detection system based on an in vitro drug metabolism mechanism has been devised. In this paper, electrochemical voltammetry was used to investigate the effect of the S9 system on the electrochemical behavior of HepG2 cells, and benzo[a]pyrene, fluoranthene, and pyrene were employed to investigate the sensitivity of electrochemical signals of cells to the cytotoxicity of drugs metabolized by the S9 system. The results showed that, within 8 h of exposure to the S9 system, the electrochemical signal of HepG2 cells at 0.7 V did not alter noticeably. The levels of xanthine, guanine, hypoxanthine, and adenine in the cells were not significantly altered. Compared with the absence of S9 system metabolism, benzo[a]pyrene and fluoranthene processed by the S9 system decreased the electrochemical signal of the cells in a dose-dependent manner, while pyrene did not change it appreciably. HPLC also revealed that benzo[a]pyrene and fluoranthene metabolized by the S9 system decreased the intracellular purine levels, whereas pyrene had no effect on them before and after S9 system metabolism. The cytotoxicity results of the three drugs examined by electrochemical voltammetry and MTT assay showed a strong correlation and good agreement. The S9 system had no effect on the intracellular purine levels or the electrochemical signal of cells. When the drug was metabolized by the S9 system, variations in cytotoxicity could be precisely detected by electrochemical voltammetry. [ABSTRACT FROM AUTHOR]

[Display omitted] • GA 3 and ICI182,780 reversely regulated the electrochemical signals of cells. • GA 3 and ICI182,780 reversely regulated intracellular purines. • GA 3 induced purine de novo synthesis by regulating PRPP amidotransferase and IMPDH. • GA 3 induced purine catabolism, mainly regulated ADA. The estrogenic effect of plant growth regulators has been received little attention, which leads to the lack of relevant toxicity data. In this study, the estrogenic effect induced by gibberellin with ERα-dependent manner was found by E-screen and western blot methods, and the electrochemical signals of MCF-7 cells regulated by gibberellin and fulvestrant were investigated. The results showed that the electrochemical signals of MCF-7 cells were increased by gibberellin, while reduced by fulvestrant significantly, and displayed an extremely sensitive response to the effects of estrogenic effect induced by ERα agonist and antagonist. Western blot results showed that the expressions of phosphoribosyl pyrophosphate amidotransferase and hypoxanthine nucleotide dehydrogenase in de novo purine synthesis and adenine deaminase in catabolism were more effective regulated by gibberellin and fulvestrant, resulting in significant changes of the levels of guanine, hypoxanthine and xanthine in cells, and then electrochemical signals. The results provide a theoretical basis for the establishment of new electrochemical detection method of the estrogenic effect of plant regulators. [ABSTRACT FROM AUTHOR]

The existing DNA damage detection technology cannot meet the current detection requirements. It is critical to build new methods and discover novel biomarkers. In this study, alkaline comet and 8-OHDG ELISA assays were used to identify DNA damage in HT-1080 cells exposed to K 2 Cr 2 O 7 , and electrochemical behaviors of HT-1080 cells with DNA damage was studied. With an increase in K 2 Cr 2 O 7 exposure time, two electrochemical signals from HT-1080 cells at 0.69 and 1.01 V steadily grew before decreasing after reaching their highest values. The electrochemical signal's initial response time and peak time decreased as the concentration of K 2 Cr 2 O 7 increased. The duration of the high dose group was 0.5 and 1 h, while the low dose group was 1.5 and 6 h. Western blotting analysis revealed that DNA damage increased the expression of proteins involved in catabolism and de novo purine synthesis, particularly de novo purine synthesis. Expressions of PRPP amidotransferase, IMPDH, and ADA were all higher than those of ADSS, XOD, and GDA, which resulted in larger concentrations of hypoxanthine, guanine, and xanthine, and in turn improved electrochemical signaling. These findings suggest that intracellular purine identified by linear scan voltammetry is predicted to evolve as a marker of early DNA damage. [Display omitted] • DNA damage promoted de novo purine synthesis and catabolism, especially the former. • DNA damage upregulated the expression of PRPP amidotransferase, IMP and ADA more. • Intracellular purines can reflect early DNA damage caused by K 2 Cr 2 O 7. • Cellular electrochemical signals may respond to changes in purine concentrations. [ABSTRACT FROM AUTHOR]

It is difficult to screen the increasing numerous chemicals in the environment for DNA damage by traditional methods. Therefore, it is urgent to find new markers and establish simple, rapid and low-cost new DNA damage detection methods. In this paper, the electrochemical behavior of Ethyl methanesulfonate (EMS)-induced DNA damage in HT-1080 cells was investigated, and the two electrochemical signals of HT-1080 cells at 0.69 and 1.03 V, respectively, coming from mixture of guanine (G) and xanthine (X) and hypoxanthine (HX) displayed parabolic changes, showing a time- and dose-dependent increase within 4 h and 5 mM, which was completely different from the trend of cell proliferation. The time- and dose-dependent DNA damage of cells exposed to EMS was detected by both alkaline comet and micronucleus assay. The HPLC found that the levels of HX, G and X in HT-1080 cells quickly rose to the peak values within 4 h, and felt back. The changes of intracellular purine levels were reliable biomarkers of DNA damage, and monitoring the content changes of intracellular purines by electrochemical method could simply and quickly evaluate the DNA damage toxicity of chemicals. This study provided a new perspective for the evaluation of DNA damage. [Display omitted] • EMS-induced DNA damage led to the increase of intracellular purine level. • The changes of intracellular purine bases could be used as markers of DNA damage. • Electrochemistry could track the level change of purine in cells when DNA was damaged. • The electrochemical signal of cells could reflect the early DNA damage. [ABSTRACT FROM AUTHOR]