5-杂氮胞苷和甲基硝基亚硝胍处理细胞DNA中5-甲基胞嘧啶含量的HPLC分析  

HPLC analysis of 5-methylcytosine contents in DNAs isolated from 5-azacytidine and MNNG treated cells

作　　者：施正政[1] 余应年[1] 陈星若[1] 

机构地区：[1]浙江医科大学病理生理教研室

出　　处：《中国病理生理杂志》1991年第6期612-615,共4页Chinese Journal of Pathophysiology

基　　金：国家自然科学基金

摘　　要：应用高效液相色谱技术对5-azaCR及MNNG处理的FL、Wish及Vero-E6细胞的DNA中5—甲基胞嘧啶(~mC)含量进行直接测量。结果表明5—aza CR(2×10^(-6)mol/L)处理细胞DNA的~mC含量较对照细胞为低(P<0.01),但在MNNG处理的FL细胞(5×10^(-6)及1×10^(-5)mol/LMNNG)及Wish和Vero-E6细胞(2及3.3×10^(-5)mol/L MNNG)中,DNA的~mC含量与对照并无差异(P>0.05)。这与用HpaⅡ限制性片段长度放射活性分析法检测新复制DNA甲基化状态的结果一致。认为文献中关于细胞DNA低甲基化是化学致癌启动过程普遍规律的结论是由于实验设计的内在缺陷所致。The 5-methylcytosine (~mC) in DNAs from 5-azacytidine and MNNG treated FL, Wish and Veto-E6 ceUs were analysed by HPLC. In 2×10^(-6)mol/L 5-azaCR treated cells, the percentages of ~mC in total cytosine were all lowered significantly (P <0.01), while in MNNG treated FL cells (treated with 5 and 10×10^(-6) mol/L MNNG), Wish and Veto-E6 cells (treated with 2 and 3.3×10^(-5) mol/L MNNG), no significant difference were found as compared with the corresponding controls (P>0.05). These results were in good agreement with those obtained by radioactivity analysis of newly replicated DNA fragments from Hpa Ⅱ digest. These results further validate the idea that DNA hypomethylation as a general pathway in the initiation process of chemical carcinogenesis is based on the results obtained by a defectively designed experiment.

关 键 词：脱氧核糖核酸 甲基胞嘧啶 致癌物 

分 类 号：R730.23[医药卫生—肿瘤]