【摘要】 目的　对结晶型硫化镍诱导转化及成瘤的人支气管上皮细胞 ( 16HBE)基因组DNA甲基化状况进行研究 ,以寻找DNA甲基化异常的基因片段 ,并探讨镍的外遗传致癌机制。方法　抽提基因组DNA后 ,采用限制性内切酶MseI单独酶切或限制性内切酶MseI与BstuI双重酶切后 ,其酶切产物采用甲基化敏感的限制性指纹识别技术 (MSRF)进行分析 ,显示的异常甲基化基因片断 ,采用TA克隆技术构建测序载体 ,对测序结果进行同源性分析比较。结果　发现结晶型NiS诱导转化及成瘤的 16HBE细胞基因组DNA存在高甲基化的DNA片段。其中一基因片段与位于 16q2 4.3编码鼻咽癌易感性蛋白基因ANKRD11同源 ( 99% ) ,另一基因片段与HOXA3基因序列同源 ( 99% )。HOXA3在脊椎动物中编码转录因子 ,编码调控基因表达 ,形态发生和变异的DNA结合转录因子。结论　结晶型NiS诱导转化及成瘤的 16HBE细胞基因组DNA的高度甲基化可能导致基因表达抑制 ,这可能是结晶型NiS诱导 16HBE细胞转化和成瘤的一种外遗传机制。更多还原

【Abstract】 Objective To study aberrant DNA methylation potentially resulting in the changes of the NiS-transformed 16 HBE cells as a possible epigenetic methanism for nickel sulfide(NiS) carcinogenesis. Methods Genomic DNA isolated from NiS-transformed 16HBE cells was analyzed with MseI (methylation non-sensitive) or with MseI and BstuI(methylation sensitive) for aberrant methylation. The product DNA was analyzed for aberrant methylation using PCR based technique—Methylation-sensitive restriction fingerpringting(MSRF). Several DNA fragments differentially methylated in the transformed cells found by MSRF were ligated to pMD-T Vector and transformed into bacteria. The plasmid DNA were sequenced and compared with data in GenBank by BLASTN. Results DNA hypermethylation was indentified in the NiS-transformed 16 HBE cells,and it was found that one of the DNA fragments homologized (99%) with ANKRD11 which encoded the susceptibility protein of nasopharyngeal carcinoma and another homologized (99%)with homeo box A3, which encoded a DNA-binding transcription factor which might regulate gene expression, morphogenesis, and differentiation. Conclusion DNA hyper-methylation is known to result in gene silencing, it appears that hypermethylation of gene may represent a possible epigenetic mechanism for NiS-induced cells transformation and carcinogenesis.更多还原