采用染色质免疫沉淀联合芯片技术分析 胃癌全基因组蛋白H3K27三甲基化水平

Genome-wide analysis of histone H3 lysine 27 trimethylation by ChIP-chip in gastric cancer

目的：研究胃癌细胞全基因组蛋白H3K27的三甲基化水平。方法：收集我科2007年10月-2008年1月间8例胃癌患者的病灶组织和正常胃黏膜组织，采用染色质免疫沉淀联合芯片技术（ChIP-chip）在全基因组范围内对两种组织细胞的组蛋白H3K27进行高通量的检测。随后采用染色质免疫沉淀-实时定量聚合酶联反应（ChIP-qPCR）验证芯片结果，定量反转录聚合酶联反应（qRT-PCR）检测H3K27显著差异基因的mRNA表达水平。用统计软件进行基因筛选。结果：经两种组织细胞组蛋白H3K27三甲基化水平对比，筛选出234个基因存在H3K27显著差异，肿瘤细胞中有71个基因显示有H3K27三甲基化程度增高，161个基因H3K27甲基化程度降低；ChIP-qPCR验证结果与CpG岛芯片检测结果一致。结论：和正常胃黏膜组织细胞相比，胃癌细胞多个基因组蛋白H3K27三甲基化存在显著改变。ChIP-chip检测技术有利于进一步揭示胃癌发生的分子机制，发现新的基因治疗靶点。

To analyze histone H3 lysine 27 trimethylation of genome-wide by ChiP-chip in gastric cancer cell. Methods：Eight cases including tumor tissue and gastric mucosa tissue in gastric cancer patients were collected from Oct. 2007, to Jan. 2008. For the first time chromatin immunoprecipitation linked to microarrays （ChiP-chip）was adopted to profile the variations in H3K27me3 in CpG island regions in tumor tissue and gastric mucosa tissue. ChIP-qPCR was used to validate the microrray results. Expression analysis by qRT-PCR was performed to confirm correlations between H3K27me3 and gene expression. Results：Two hundred and thirty-four （71 increased and 161decreased） gene displayed significant H3 K27me3 differences were found in tumor cell compared with gastric mucosa tissue. The results of ChIP-qPCR were coincided well with microarray. Conclusion：There are significant differences in H3K27me3 profiling between tumor tissue and gastric mucosa tissue, these novel candidate genes may be become potential biomarkers or future therapeutic targets. The ChiP-chip technology will help further reveal gastric cancer molecular mechanisms and discover new therapeutic targets.