细胞周期调控关键基因的肺癌易感位点鉴定及功能分析

Precise regulation of cell cycle is a highly-ordered process, which involves a series of checkpoints and multiple key regulators. The genetic alterations of the key process genes may lead to disruption of the normal cell cycle progress, following by genome instability and lung cancer pathogenesis. Moreover, the major cell cycle regulators are also used as the main targets for therapeutic intervention of lung cancer patients.In the previous studies, we have analyzed 4621 single nucleotide polymorphisms (SNPs) of 161 key process genes of cell cycle in 2331 Chinese lung cancer patients and 3077 controls, and found that 32 tag SNPs in 21 genes were associated with lung cancer risk. As a result, in the present study, we aim to investigate the associations between these genetic variations and lung cancer susceptibility and prognosis in two additional 2500 pairs of lung cancer cases and control in Wuhan and Beijing cohorts, respectively. We will further evaluate the effects of the gene-gene, gene-environment interactions in this large-scale population. The biological mechanisms of the identified positive SNPs, especially SNPs locate in the gene regulation region and the missense SNPs, will be further assessed by the functional studies, including the reporter assay, electrophoretic mobility shift assay, co-immunoprecipitation, and western blotting in the normal and tumor lung tissues. This study will make a deep description about the biological effects of the major cell cycle regulators on the development of lung cancer. The identified functional SNPs will provide new insight into high-risk population screening and prognosis prediction of lung cancer patients.

细胞周期的精确调控涉及到多个关键控制点的大量基因的参与，这些关键基因的遗传变异可能导致正常的细胞周期调节失控，继而引起基因组不稳定和肺癌的发生。细胞周期相关基因同时也是目前肺癌药物治疗的主要靶点。本课题前期在5408例肺癌病例-对照人群中研究发现21个细胞周期关键基因的32个标签性SNPs位点与中国汉族人群发病有关，本项目拟在这一结果的基础上采用多中心、两阶段肺癌病例-对照研究（各2500对）和单纯肺癌患者预后研究，全面系统地探讨细胞周期关键基因的遗传变异单独作用、基因-基因、基因-环境交互作用与中国汉族人群肺癌发生风险和预后的关系；同时对发现的阳性位点，尤其对具有潜在调控功能的和具有基因-基因交互作用的遗传变异，进行生物学机制的深入探讨。本研究将进一步加深细胞周期调控关键基因与肺癌发生和预后关系的认识，研究发现的阳性遗传变异可为筛检我国肺癌发病的高危人群和监测肺癌患者的预后提供科学依据。

本项目原计划书主要着眼于研究细胞周期调节相关基因的遗传位点与中国汉族人群肺癌发生风险的关联，实际工作中，除研究细胞周期调节通路基因外，我们还研究了细胞凋亡、氧化应激、炎性免疫和DNA修复通路关键基因遗传位点在影响中国汉族人群肺癌易感性的作用，对本项目的研究内容进行了扩大和延伸。在本项目的资助下主要取得了以下研究成果：（1）在肺癌GWAS研究的基础上，采用三阶段肺癌病例对照研究设计（共6464肺癌病例和7599正常对照人群）发现细胞周期调节基因CDK6 rs2282987与细胞凋亡基因SH3RF1 rs2706748是中国汉族人群肺癌的易感性位点，且此两个位点与吸烟在提高肺癌发生风险上具有交互作用(Carcinogenesis. 2013)；（2）发现细胞凋亡通路关键基因BCL2基因3’UTR rs1564483能降低中国汉族男性肺癌发生风险，提高晚期男性NSCLC的死亡危险度(PLoS One. 2013)；（3）发现DNA修复基因APEX1遗传变异与PAHs在提高染色体损伤上具有联合作用，并与吸烟在提高肺癌发生风险的交互作用(Mol Carcinog. 2015)；（4）发现DNA修复基因ERCC2 rs50872 和XRCC1 rs25487 遗传变异可以影响中国汉族人群晚期NSCLC的预后(Cancer Med. 2016)；（5）发现端粒逆转录酶TERT基因 rs2857669 和rs2736108可能通过调节端粒长度和TERT mRNA表达影响早期NSCLC患者生存结局(Cancer Gene Ther. 2016)；（6）发现同时暴露于高浓度的多环芳烃和重金属（如砷、镉、铬、镍和铅）在提高个体氧化应激水平上具有交互作用，高浓度的砷、铬、镍能提高个体的肺癌发生风险(Environ Res. 2015)；（7）发现超重和/或肥胖(BMI≥25)男性与正常体重(BMI=18.5~24.9)的男性相比，外周血染色体损伤水平及肺癌发生风险均显著降低(Sci Rep. 2015)；（8）发现长期夜间倒班史(>20年)、无午休习惯可能提高男性肿瘤的发生风险，而过多的夜间睡眠(>10小时)与男性肿瘤发病率和死亡风险增加有关(Ann Med. 2016)，上述研究结果为说明细胞重要信号通路关键基因、个体特征及环境因素在肺癌发生和预后中的作用提供了科学依据。