NER系统基因miRNA-SNPs与肺癌遗传易感的关联及机制研究

Lung cancer is a complex process involved in genes and other factors, and its occurrence and development resulted from genetic and environmental interaction. Nucleotide excision repair (NER) is an important defense mechanism of the body to exogenous carcinogens and mutagens, such as benzo[a]pyrene (B[a]P). Research shows that DNA repair ability is the important factor to cancer susceptibility and DNA repair ability is closely related with single nucleotide polymorphisms (SNPs) and MicroRNAs (miRNAs). SNPs are the most abundant form of DNA variation in the human genome. A miRNA can bind to the 3’ untranslated region (UTR) of its target mRNA to post-transcriptionally regulate genes. Studies have shown that miRNAs play a role in several biological processes, including embryonic development, cell proliferation and differentiation, apoptosis, fat metabolism, atherosclerosis and oncogenesis. SNPs within the binding site of miRNA can affect miRNA-induced genetic repression. If an SNP can influence the binding of a miRNA to its target gene, this SNP is called a miRNA-SNP. Therefore, miRNA-SNPs can affect gene expression levels to influence susceptibility to disease. In the present study, we found that XPB and XPG are associated with the risk of lung cancer in Hainan. In addition, we will consider the genetic susceptibility of lung cancer in Li population. Therefore, we aim to identify miRNA-SNPs in the genes of NER pathways that may influence risk of lung cancer in Hainan. The combination of population investigations and functional studies related to miRNA-SNPs will provide powerful approaches for molecular epidemiological association studies in predicting lung cancer risk.

肺癌是严重威胁人类健康的公共卫生问题。NER系统基因的单核苷酸多态性 (SNP) 以及非编码RNA (miRNAs) 表观遗传调控和肿瘤遗传易感的关联研究颇受关注。前期研究发现，海南汉族人群中，NER系统基因多态及单体型可增加肺癌的发病风险。XPB、XPD、XPG基因3′UTR的SNP可能干扰miRNAs功能而异常调控靶基因表达水平，从而影响肺癌的遗传易感性，值得进一步探讨。另外，我们还需关注海南地区少数民族黎族人群。因此，本项目拟选择海南地区肺癌人群为研究对象，采用病例对照研究方法，检测XPD rs3916843 (A>G)，XPG rs873601 (G>A) 基因多态，分析其与肺癌患者发病风险的关联。采用microRNA芯片技术检测五个miRNA表达水平。构建候选miRNA-SNP转染细胞模型，与人群研究结果相结合，得到肺癌遗传易感关联的NER系统基因miRNA-SNPs。

肺癌是严重威胁人类健康的公共卫生问题。NER系统基因的单核苷酸多态性 (SNP) 以及非编码RNA (miRNAs) 表观遗传调控和肿瘤遗传易感的关联研究颇受关注。本项目在海南地区汉族人群中，纳入300例肺癌患者和300例非肺癌患者，检测XPG rs873601、ERCC1 C8092A位点SNP；检测XPB、XPD、XPG基因mRNA表达水平和miRNA-4715-3p、miRNA-466、miRNA-486-3p、miRNA-10b-5p、miRNA-200a-3p表达水平。调查120例以铂类药物为基础进行化疗治疗的肺癌患者的化疗及生存期情况。同时，体外构建Has-miR-486-3p过表达转染细胞系，以不同浓度苯并芘分别处理各转染细胞6h, 12h, 24h, 48h（染毒24h，洗后继续培养24h）。qPCR法检测各组细胞Has-miR-486-3p表达水平；MTT实验、Rad51免疫荧光实验检测细胞损伤修复水平。人群结果发现miRNA-4715-3p、miRNA-466、miRNA-10b-5p低表达，miRNA-486-3p高表达的人群具有较高的肺癌易感性。miRNA-4715-3p和XPG mRNA之间存在调控关系，年龄和XPG rs873601位点多态可影响肺癌患者XPG mRNA表达水平。XPG rs873601位点AA基因型肺癌患者的化疗有效率显著高于其他基因型，可用于预测铂类药物的化疗疗效。但双荧光素酶报告实验并未发现hsa-miR-4715-3p与h-XPG基因3’UTR的相互作用。体外实验结果发现5µM苯并芘处理Has-miR-486-3p过表达转染细胞24h，Has-miR-486-3p表达量最高；10µM苯并芘处理Has-miR-486-3p过表达转染细胞48h，Has-miR-486-3p表达量最高。