Cytotoxicity of acrylamide and its epoxide glycidamide in CHO cells expressing human cytochrome P450 2E1

Objective: To investigate whether CYP2E1 is responsible for the acrylamide metabolic activation in Flp-In CHO cell system. Methods: CYP2E1 cDNA was subcloned from the human liver full-length cDNA library and subsequently transfected into the Flp-In CHO cells to generate the stable transfectant of CYP2E1. The CYP2E1 mRNA expression was determined by RT-PCR. Acrylamide and its epoxide glycidamide induced cytotoxicity and cell cycle arrest in G2/M were conducted using MTS assay and flow cytometry, respectively. Results: In the CHO cell stably expressing CYP2E1 (CHO-2E1), a ~1.5 kb size of band was detected from the mRNA in the cells while no corresponding band in the CHO-vector cells, which indicated that CYP2E1 was successfully transfected in the CHO cells. Compared with the CHO-vector cells, acrylamide showed a concentration-dependent loss of viability in the CHO-2E1 cells but no significant change of G2/M arrest was found. As expected, glycidamide induced similar profile of cytotoxicity in both of the cells, and G2/M arrest presented a concentration-dependent increased in the CHO-2E1 cells. Conclusion: The result suggested that CYP2E1 might be responsible for the acrylamide metabolism, and its metabolite glycidamide was a direct cytotoxic and genotoxic agent. It should be further considered whether acrylamide-induced toxicity is through its epoxide glycidamide in the presence of CYP2E1.