长链非编码RNA作为ceRNA与膀胱癌易感性的机制研究

Long non-coding RNA (lncRNA) can interact with the miRNA as a competing endogenous RNA (ceRNA), contributing to the occurrence and development of cancer. Our previous study has identified a series of differently expressed lncRNAs and genetic variant of lncRNA in bladder cancer. However, the function of ceRNA for lncRNA could be regulated by the SNPs in miRNA response elements (MREs). Hence, based on our previous results, we will identify the MREs for differently expressed lncRNA as well as SNPs in MREs using the lncRNA expression array and bioinformatics. We will perform a case-control study to investigate the association between SNPs in MREs and bladder cancer risk as well as the interactions on gene-gene, gene-environment, and genotypes and clinical phenotypes. Further using a series of molecular biology methods, we will explore the effect of SNPs involving in lncRNA acting as ceRNA, and elucidate the regulator mechanism of lncRNA-miRNA-target genes. The present study will reveal the biological mechanism of lncRNA acting as ceRNA associated with the risk of bladder cancer.

长链非编码RNA（lncRNA）可作为竞争内源性RNA（ceRNA）与miRNA之间互相调控，从而参与肿瘤发生发展。课题组前期已发现膀胱癌中存在大量差异表达lncRNA及其遗传变异，而lncRNA发挥ceRNA作用时可能受到miRNA反应元件（MREs）结合区域单核苷酸多态性（SNPs）的影响。因此，本项目在前期的研究基础上，拟通过表达谱芯片和生物信息学确定膀胱癌差异lncRNA发挥ceRNA作用的MREs结合区域SNPs，利用病例-对照研究方法分析该区域SNPs与膀胱癌发病风险的关系；并分析基因-基因、基因-环境交互作用以及基因型与临床表型的关联性；同时运用一系列分子生物学方法，进一步探讨SNPs对lncRNA作为ceRNA竞争抑制miRNA调控靶基因的影响，阐明lncRNA-miRNA-靶基因的生物学调控机制，最终揭示lncRNA作为ceRNA在膀胱癌易感性的作用及其生物学机制。

长链非编码RNA（lncRNA）作为竞争内源性RNA（ceRNA）与miRNA相互作用，共同调控下游靶基因参与肿瘤发生发展的研究备受关注。本研究基于膀胱癌细胞不同细胞亚定位RNA-Seq和TCGA公共数据库，筛选出22条膀胱癌差异性lncRNAs；结合生物信息学分析，发现1,268个位于差异性lncRNAs的miRNA反应元件（MREs）结合区域的SNPs。采用两阶段病例-对照研究，发现位于lncRNA BCCE4 MREs结合区域的rs62483508 G>A遗传变异能够显著降低膀胱癌的发病风险（第一阶段：OR = 0.62，95%CI = 0.44-0.83，P = 2.00×10-3；第二阶段：OR = 0.77，95%CI = 0.61-0.97，P = 2.45×10-2）。进一步发现携带rs62483508 AA/AG基因型的个体其lncRNA BCCE4表达水平显著下调，同时抑制膀胱癌细胞增殖、侵袭与转移等相关恶性表型。通过生物信息学分析、荧光素酶报告基因等实验发现，rs62483508 G>A遗传变异可阻遏lncRNA BCCE4作为ceRNA与miRNA-328的结合能力，进而降低下游靶基因NRBP1表达水平。综上所述，lncRNA BCCE4 MREs结合区域的rs62483508遗传变异可降低膀胱癌的发病风险，rs62483508可能通过调控lncRNA BCCE4与miRNA-328结合能力，影响靶基因NRBP1表达水平，进而引起膀胱癌细胞恶性表型改变，最终参与膀胱癌病理进程。该研究发现有助于从lncRNA作为ceRNA的角度系统性阐释其作用与具体生物学机制，为膀胱癌早期筛查、诊断、防治措施提供重要的科学依据。