长链非编码RNA MDC1-AS遗传变异与膀胱癌发病风险的机制研究

Long non-coding RNAs (lncRNAs) is functional non-coding RNAs longer than 200 nucleotides without protein-coding capability, and involved in the development and progression of cancer. The mechanism of genetic variation of lncRNAs promoting pathogenesis of bladder cancer is not clear.Our previous studies have found that expression of lncRNA MDC1-AS was significantly lower in bladder cancer tissues than that in normal tissues, and implicated in development of bladder cancer by modulating the function of the complementary gene MDC1. Different genetic variants(single nucleotide polymorphisms,SNPs) located on lncRNA MDC1-AS was also found.So we raise a hypothesis: the genetic variants located on lncRNA MDC1-AS was related with susceptibility of bladder cancer,and effect its function by regulating the expression of genes encoded its complementary strand, and consequently participated in the development of bladder cancer. We plan to investigate the relationship between SNPs at lncRNA MDC1-AS and risk for bladder cancer in a case-control study. Furthermore, we will explore the molecular mechanism between the functional SNPs and modulation of MDC1-AS. This study is hopefully to discover the the relationship between SNPs at lncRNA MDC1-AS and susceptibility of bladder cancer,and to provide a novel target and important theoretical support for early screening and etiology of bladder cancer.

长链非编码 RNA（lncRNA）已证实与肿瘤发生密切相关，但其序列相关的遗传变异对膀胱癌发生的意义和机制尚不清楚。我们前期发现lncRNA MDC1-AS参与膀胱癌发生过程，其机制为通过其互补区反义结合MDC1 mRNA，增加其稳定性和表达。并发现MDC1-AS存在多个单核苷酸多态性（SNP）位点。由此我们提出假说：lncRNA MDC1-AS基因遗传变异与膀胱癌易感性显著关联，关联SNPs位点可通过影响MDC1基因参与膀胱癌的发生发展。本项目在前期研究基础上，拟通过病例-对照研究方法探讨lncRNA MDC1-AS基因的遗传变异与膀胱癌发病风险的关系；在此基础上，采用分子生物学方法，研究遗传变异对MDC1-AS及其靶基因MDC1的功能学影响和潜在的分子机制。希望通过本研究阐明MDC1-AS遗传变异与膀胱癌易感性的关系，为膀胱癌早期筛检及病因学研究提供新的靶点和理论依据。

长链非编码 RNA（lncRNA）已证实与肿瘤发生密切相关，但其序列相关的遗传变异对膀胱癌发生的意义和机制到目前仍不清楚。我们前期的工作已经证实lncRNA MDC1-AS参与膀胱癌发生过程，并发现MDC1-AS存在多个单核苷酸多态性（SNP）位点。我们提出了如下假说：lncRNA MDC1-AS基因遗传变异与膀胱癌易感性显著关联，关联SNPs位点可通过影响MDC1基因参与膀胱癌的发生发展。前期实验结果证实在肿瘤细胞中过表达MDC1-AS 后，相对于转染NC 的细胞，其能明显抑制膀胱癌细胞的增殖、转移、侵袭以及平板克隆能力，表明MDC1-AS能够显著抑制膀胱癌细胞恶性表型，MDC1-AS中单核苷酸多态性的影响可能与膀胱癌的易感性相关。我们通过生物信息学方法筛选tagSNPs位点，并最终确定rs116665440位点为研究对象。我们成功构建了不同基因型的MDC1-AS1过表达稳定株，通过细胞增殖实验、平板克隆形成实验、肿瘤细胞迁移和侵袭实验以及裸鼠荷瘤实验等实验技术，从多角度、多层面较为系统地阐述了不同基因型MDC1-AS对膀胱癌细胞恶性表型的影响具有明显的差异。实验结果显示SNP rs116665440的野生型（CC）过表达能够抑制膀胱癌肿瘤细胞增殖及迁移、侵袭能力；SNP rs116665440的突变型（TT）过表达能够进一步抑制肿瘤细胞增殖及迁移、侵袭能力。该结果提示lncRNA MDC1-AS基因SNP rs116665440位点与膀胱癌易感性存在显著关联，SNP rs116665440的T等位基因突变可能会降低膀胱癌的发生风险。该研究能够为膀胱癌早期筛检及病因学研究提供新的靶点和理论依据，并为个体化治疗及预测患者的预后提供重要的基础研究证据。