MicroRNA-3131及其遗传多态在肝细胞肝癌发生发展中的作用机制研究

Multiple evidences had indicated that genetic polymorphisms within miRNAs were associated with a variety of malignancies. Most of the studies were focused on the associations of cancer susceptibility and prognosis, however, the molecular mechanisms underling these associations were still not fully elucidated. Our preliminary study discovered that the expression level of miR-3131 in hepatocellular carcinoma (HCC) tissues was significantly higher than that of adjacent non-HCC tissues. Meanwhile, the “CTT” insertion/deletion polymorphism (rs57408770) within pre-miR-3131 was associated with HCC risk and prognosis. Further studies demonstrated that there was a significant correlation between rs57408770 genotype and miR-3131 expression in vivo and in vitro. Using bioinformatics prediction, we found that rs57408770 may influence miR-3131 or iso-miR-3131 expression by interrupting its interaction with splicing factor SRp-20, which in turn regulating miR-3131 maturation and iso-miR-3131 expression, thereby involving in the development of HCC. On the basis of above results, our present proposal plans to clarify the roles of miR-3131/ iso-miR-3131 mediated by rs57408770 in HCC progression with multiple methods, such as two-center large sample analysis, mechanisms exploring and phenotype-function investigations, to provide scientific basis and effective means for screening, prevention, treatment, and prognosis of high-risk HCC populations.

研究表明miRNAs当中蕴藏的遗传多态与多种恶性肿瘤存在密切联系，但多数研究仅停留在多态与肿瘤发生及预后的关联分析，其中的具体分子机制鲜见报道。前期预实验中我们发现肝细胞肝癌（HCC）组织中miR-3131表达量显著高于癌旁组织，位于miR-3131前体内的三碱基插入缺失多态（rs57408770）与HCC的发生及预后存在显著关联，而且该多态的基因型与miR-3131表达量相关，但其中的具体机制尚不明确。初步实验提示该多态可能通过影响SRp20剪切因子与靶序列的结合，从而影响miR-3131成熟体表达量或异构体的形成，进而参与HCC的发生及发展。本项目拟在此基础上，通过双中心大样本分析、机制研究及功能表型实验等方法系统阐明该多态通过调控miR-3131及其异构体的表达进而参与HCC发生发展的具体分子机制，为HCC高危人群的筛查、预防、治疗及预后评估提供可靠的理论依据和手段。

本项目首次证实miR-3131前体内的遗传多态（rs57408770）与肝细胞肝癌（HCC）的发生存在显著关联，通过双中心、大样本量的病例对照分析完成遗传多态与肿瘤易感性的关联分析，通过分子生物学方法及功能分析继续深入研究了遗传多态在HCC发生发展过程中的分子机制，获得了遗传多态rs57408770参与HCC发生发展的可靠证据。本课题组继续对相关领域进行研究，完成了对一个位于核仁小RNA-SNORD105上的遗传多态与HCC关联性的研究，完善了非编码RNA参与肿瘤发展的相关研究，为最终阐明Indels影响肿瘤易感性的分子机理和设计特异性的肿瘤诊疗途径奠定了一定基础。而后综合考虑法医分子遗传学领域热点问题及本单位、课题组可利用的样本资源，选择对猝死的分子遗传学机制展开探索，并完成了一系列创新性研究，将为猝死高危人群的干预和预防提供有价值的理论依据和评估指标，对实现法医学分子解剖提供重要帮助。