关键词: 遗传毒性, Bhas 42细胞转化, 促癌活性, 非遗传毒性致癌物, 染料木黄酮

Abstract: OBJECTIVE: To establish a high-throughput screening method of cell transformation assay for carcinogens detection using Bhas 42 cell line,and evaluate the potential carcinogenic risk of genistein. METHODS: We established Bhas 42 cell transformation assay and compared the effects of traditional foci formation as well as H₂O₂ treatment methods on data analysis. In the traditional foci formation method,cells were fixed and dyed on day 21 after plating,whereas in the H₂O₂ treatment method,cells were treated with H₂O₂ for 24 h before dyeing and the transformation ratio measured at D(450) on day 20. Then the transformation potential of genistein on Bhas 42 cells was determined by the H₂O₂ treatment method,after a dose range-finding assay was performed to estimate the concentrations of genistein to be used based on the growth rates of cells. RESULTS: Apparent increase in the number of wells with transformed foci were noted in the positive control (3-MCA) in the initiation assay and the positive control (TPA) in the promotion assay,compared with the negative control in the traditional foci formation method(P<0.01). Meanwhile,apparent increase in the number of wells with transformed foci and D(450) values were noted in the positive control (3-MCA) in the initiation assay and the positive control (TPA) in the promotion assay,compared with the negative control in the H₂O₂ treatment method(P<0.01). The effects of genistein on Bhas 42 cell line was also examined. Although the D(450) values showed no difference between negative control and groups treated with genistein (0.03,0.1,0.3,1,3 μg/mL) in the initiation assay,a significant difference was noted in the promotion assay with the concentrations of genistein ranging from 0.03 to 3 μg/mL(P<0.01). CONCLUSION: This study has clearly demonstrated the H₂O₂ treatment method as a reliable improvement for Bhas 42 cell transformation assay. This cell transformation assay combined with initiation and promotion models is an effective and practical screening platform for non-genotoxiccarcinogens.,and it will be extremely helpful in the early stage of new drug development. Genistein could be a potential non-genotoxic carcinogen,however,this result needs to be further confirmed.

Key words: genetic toxicity, Bhas 42 cell transformation, promotive activity, non-genotoxic carcinogens, genistein