肝细胞癌相关长链非编码RNA的发现及其功能和分子机制研究

Long non-coding RNA (lncRNA) regulates gene expression in multiple levels, including transcriptional, post-transcriptional and epigenetic modification. LncRNA presents various biological functions and complicated mechanisms, and is found involved in the development of multiple diseases, such as hepatocellular carcinoma (HCC). To identify HCC- related lncRNAs, the mRNA and lncRNA expression profiles of paired tumoral and peritumoral tissues from 40 HCC patients were obtained. By “integrative omics” strategy, several novel HCC- related lncRNAs were identified. Among them, the ASLNC18598 was shown to suppress the HCC cells proliferation through P53 signal pathway. Meanwhile, the ASLNC18342 was shown to promote the migration of HCC cells. Further, by cluster analysis of gene expression profile, the ASLNC18342 was shown to regulate the histone methylation of migration-associated genes. In this project, we will focus on following objects: 1) Clarifying the roles of ASLNC18598 and ASLNC18342 in the development of HCC; 2) Clarifying the underlying mechanisms and molecular network of ASLNC18598 and ASLNC18342; 3) Analyzing the relationship between the abnormal expression of these two lncRNAs and tumor processes such as tumorigenesis, progression, metastasis and recurrence.

长链非编码RNA（lncRNA）在转录、转录后，以及表观遗传水平等多个层面调控基因的表达，具有多样化的生物学功能和作用机制，与肿瘤的发生发展密切相关。为鉴定与肝癌发生发展相关的lncRNAs，我们前期通过“整合组学”方法分析了40例肝癌患者的癌和配对癌旁组织的mRNA和lncRNA表达谱，发现了多个全新的肝癌相关的lncRNAs。其中lncRNA ASLNC18598可抑制肝癌细胞的增殖，并可能通过P53通路发挥作用；另一lncRNA ASLNC18342可促进肿瘤细胞的迁移，并可能通过影响组蛋白的甲基化修饰实现对靶基因的表观遗传调控。本项目拟在上述前期工作基础上，进一步系统研究这两个新型肝癌相关lncRNA的肿瘤生物学行为，确证其癌基因或抑癌基因作用；揭示其作用机制及其分子调控网络；揭示其在肝癌中异常表达的机制，及其与肝癌发生、分型、复发和转移等的临床相关性，为未来的应用研究奠定基础。

长链非编码RNA（lncRNA）在转录、转录后，以及表观遗传水平等多个层面调控基因的表达，具有多样化的生物学功能和作用机制，与肿瘤的发生发展密切相关。我们针对本课题组前期通过“整合组学”发现的3个lncRNA（ASLNC18598、ASLNC18342和LINC00294）和1个小核仁RNA（SNORA18L5）开展了系统的功能、机制及临床相关性研究。我们证实ASLNC18598通过调控其相互作用蛋白hnRNP K的SUMO化修饰进而增强p53的稳定性和活性，诱导细胞周期G0/G1期阻滞发挥抑癌基因功能；ASLNC18598在肝癌中异常低表达且其低表达与肝癌患者的不良预后显著相关。ASLNC18342通过与剪切因子PTBP1相互作用促进细胞增殖和转移从而发挥癌基因的作用；ASLNC18342在肝癌中异常高表达且其高表达与肝癌患者的不良预后显著相关。肝癌易感基因小核仁RNA SNORA18L5可显著促进核糖体RNA（rRNA）的成熟和核糖体的生物合成进程，缓解核糖体应激压力，阻滞核糖体蛋白RPL5和RPL11的核仁-核质易位，从而解除对MDM2的抑制作用，最终促进MDM2介导的p53泛素化降解，发挥癌基因功能；SNORA18L5在肝癌中异常高表达并且其高表达与肝癌患者的不良预后显著相关。LINC00294通过竞争性结合miR-361-3p而上调其靶基因ZFP36发挥抑癌基因的功能；LINC00294的低表达与肝癌患者的不良预后显著相关。上述研究结果进一步完善了现有的细胞癌变理论体系；同时，探索了它们作为肝癌干预新靶点的潜在临床意义，为肝癌的生物标志物和抗癌药物研发提供了理论依据，为探索肝癌防诊治的新途径奠定了基础。