鼻咽上皮细胞癌变与DNA甲基化特征的相关性研究

Study on the correlation of nasopharyngeal epithelium canceration with DNA methylation features

目的探讨鼻咽上皮细胞癌变前后DNA甲基化特征。方法 6例鼻咽癌患者作为研究对象(包括鼻咽癌变前后自身对照标本3例),5例鼻咽炎患者作为对照,获取鼻咽组织标本,常规抽提DNA,染色质免疫共沉淀联合芯片技术检测全基因组DNA甲基化状况。结果鼻咽上皮细胞癌变后,CpG岛及启动子区基因发生明显甲基化。癌变组织CpG岛甲基化峰为3258±358个,鼻咽炎组织CpG岛甲基化峰为1974±710个,t=22.32,P<0.001;癌变组织启动子区甲基化基因为1307±484个,鼻咽炎组织启动子区甲基化基因为758±363个,t=6.6,P<0.01。这些甲基化基因涉及抑癌基因、细胞信号传导通路、细胞代谢活性等多个途径。结论 DNA甲基化参与了鼻咽上皮细胞癌变过程。

Objective To investigate the correlation of nasopharyngeal epithelium canceration with DNA methylation features based on an experimental study on clinical samples. Methods Included in this study were 6 patients with nasopharyngeal carcinoma （NPC）, including 3 cases with their nasopharyngeal samples taken before canceration and after NPC developed, and 5 cases with nasopharyngitis as controls. Their nasopharyngeal tissue samples taken were routinely prepared by the procedures of paraffin imbedding and DNA was extracted from thick sections of paraffin block. Then, extracted DNA was broken by ultrasound procedure into fragments with a longth about 200 to 500 bp, and DNA-chromatin immune coprecipiUtion joint chip technology was utilized to test the whole genome DNA methylation sUtus. Results Methylation level in CpG islands and promoter region gene was significantly higher in the tissue samples of nasopharyngeal carcinoma （3258±358 methylation peaks） than that of nasopharyngitis （1974±710 methylation peaks） （t=22.32, p〈0.001）;. It was also the same situation for methylation level in the region of promoter, with very higher methylation peaks in nasopharyngeal carcinoma tissues （1307±484） than that in the tissue samples of nasopharyngitis （758±363） （t=-6.6, p〈0.01）. These genes with much higher methylation level involved those of turnor suppressor gene, signal transduction path way, cellular metabolism and some other aspects. Conclusions DNA methylation may be involved in the carcinogenesis of nasopharyngeal epithela