HIF基因3'UTR区SNP参与胰腺癌HIF-1α表达调控的分子机制及功能研究

Pancreatic cancer is a highly aggressive disease with a grim prognosis. HIF-1α expression correlates with clinicopathological parameters of pancreatic cancer, such as tumor's grades, stages and lymph-node metastasis. HIF-1α protein was constitutively expressed in pancreatic cancer tissues and cell lines. The molecular events underlying this remain poorly defined. We have found that Polymorphisms in the hypoxia-inducible factor-1α gene confer susceptibility to pancreatic cancer. MicroRNAs (miRNAs) are evolutionarily conserved small non-coding RNAs that regulate gene expression. MiRNAs play key roles in regulating the translation and degradation of mRNAs through base pairing to partially complementary sites in the 3'UTR of the message. Polymorphisms in 3'UTR of several genes have been reported to affect gene expression, but the mechanism is not fully understood. In this study, we investigated the effect of SNPs, which locate in the 3'UTR of HIF-1α. We want to use the molecular biology experiments to test the regulation mechanisms of the SNP, and evaluation the SNP genotypes, which was a risk genotype for pancreatic cancer development and was also associated with pancreatic cancer clinicopathological parameters and poor survival. This study may provide a new tumor marker or potential target for pancreatic cancer treatment.

胰腺癌是严重危害人类健康的恶性肿瘤。HIF-1α表达水平与胰腺导管腺癌的病理分级、淋巴结转移和不良预后呈正相关，但其在胰腺癌中独特的组成型高表达的机制尚不明确。课题组前期研究发现多个 HIF-1α相关SNP参与胰腺癌HIF-1α表达调控，部分SNP被证明作为胰腺癌易感基因型。近年研究发现micro-RNA是参与细胞内转录后调控的重要分子，靶序列的单核苷酸多态性变异会破坏micro-RNA的结合与转录后调控，影响靶基因的表达。本项目选取胰腺癌乏氧微环境核心调控因子 HIF-1α 3'非编码区micro-RNA靶序列相关SNP，探讨不同等位基因型对胰腺癌细胞HIF-1αmRNA及蛋白表达水平的影响，进一步探索micro-RNA相关SNP对胰腺癌细胞恶性生物学行为的影响，并通过分子生物学和细胞学功能实验分析其作用模式和调控机制，这些研究将为探索胰腺癌分子标志物和寻找治疗靶标提供有益帮助。

胰腺癌是严重危害人类健康的恶性肿瘤。HIF-1α表达水平与胰腺导管腺癌的不良预后呈正相关，但其在胰腺癌中独特的组成型高表达的机制尚不明确。课题组前期研究发现多个HIF-1α相关SNP参与胰腺癌HIF-1α表达调控，部分SNP被证明作为胰腺癌易感基因型。近年研究发现micro-RNA是参与细胞内转录后调控的重要分子，靶序列的单核苷酸多态性变异会破坏micro-RNA的结合与转录后调控，影响靶基因的表达。本项目选取胰腺癌乏氧微环境核心调控因子HIF-1α3’非编码区micro-RNA靶序列相关SNP，探讨不同等位基因型对胰腺癌细胞HIF-1αmRNA及蛋白表达水平的影响，进一步探索micro-RNA相关SNP对胰腺癌细胞恶性生物学行为的影响，并通过分子生物学和细胞学功能实验分析其作用模式和调控机制，为探索胰腺癌分子标志物和寻找治疗靶标提供有益帮助。HIF-1α rs2057482单核苷酸多态性（SNP）在410个PDAC病例和490个健康对照中进行基因分型。与CT / TT等位基因组相比，CC基因型SNP HIF-1α与PDAC风险（OR = 1.719,95％CI：1.293-2.286）和较短的总体存活率（OS，P <0.0001）显着相关。 rs2057482的C / T变体（位于HIF-1α中的miR-199a结合位点附近的SNP）可以导致miR-199a对HIF-1α的差异调节。具体来说，rs2057482的C等位基因削弱了miR-199a诱导的HIF-1α表达对mRNA和蛋白质水平的抑制。在PDAC组织中，具有rs2057482-CC基因型的个体比具有rs2057482-CT / TT基因型的个体表达显着更高水平的HIF-1α蛋白（P <0.0001）。 SNP HIF-1α的CC基因型和增加的HIF-1α表达与PDAC患者的OS更短显着相关。通过TNM分期，分化等级和CA19-9水平调节后，SNP HIF-1α和HIF-1α表达均对OS具有高度显着性（P <0.0001）。总结起来讲，我们的研究表明宿主遗传变异可以扰乱miR-199a / HIF-1α调节环的调节，并改变PDAC风险和不良预后，rs2057482-CC基因型增加对PDAC的易感性并与癌症进展相关，这提示种系遗传变异对调节HIF-1α基因和PDAC风险中miRNA基因调控环节稳态的重要性。