杂色曲霉素对人胚胃粘膜细胞p53基因致突变研究

Mutation of p53 Gene in Human Fetal Gastric Mucosal Cells by Sterigmatocystin in Vitro

为探讨杂色曲霉素（ＳＴ）的致癌作用，运用细胞培养、流式细胞术（ｆｌｏｗｃｙｔｏｍｅｔｒｙ，ＦＣＭ）和银染ＰＣＲ－ＳＳＣＰ等方法研究了不同浓度的ＳＴ（１ｍｇ／Ｌ和３ｍｇ／Ｌ）诱发体外培养的人胚胃粘膜细胞恶性转化情况以及此过程中抑癌基因ｐ５３在蛋白及基因水平上的变化。结果表明，ＳＴ处理４周后处理细胞增殖旺盛，并出现恶性转化灶；ＳＴ处理２４周后处理细胞可在软琼脂上形成细胞集落（ＳＴ１ｍｇ／Ｌ和３ｍｇ／Ｌ组每皿细胞集落数平均分别为１５和１７个）；ＦＣＭ检测结果表明，ＳＴ处理的细胞细胞增殖指数增高，ＤＮＡ含量增高，出现ＤＮＡ异倍体，突变型抑癌基因ｐ５３蛋白表达明显增强。ＰＣＲ－ＳＳＣＰ分析结果显示，ＳＴ处理２２周后，处理细胞ｐ５３第８外显子出现异常泳动带型。

Cell culture, flow cytometry and silver staining PCR SSCP methods were used to explore the effects of sterigmatocystin(ST) (1mg/L and 3mg/L) on carcinogenesis and mutation of tumor suppressor gene p53 in human fetal gastric mucosal cells in vitro. Four weeks after treated with ST, the cells showed vigorous growth and malignant transformation foci. Twenty four weeks after ST treatment, the cells could form cellular colonies in soft agar(the mean colony number was 15 and 17 perdish for ST 1mg/L and 3mg/L groups respectively).Flow cytometric analysis showed that both proliferation indexes (PI) and the cellular DNA contents of ST treated cells were much higher than those of normal control. The DNA contents of ST treated cells were in DNA aneuploid range. Mutant p53 protein expression was also significantly higher in ST treated cells. Silver staining PCR SSCP analysis showed that abnormal electrophoretic migration bands could be seen at exon 8 of p53 gene in ST treated groups 22 weeks after ST treatment, while no abnormal bands were found in control group. Thus, the results further confirmed the carcinogenic effects of ST on human fetal gastricmucosal cells.