长链非编码RNA-HCAL调控肝细胞肝癌恶性表型的分子机制研究

Long noncoding RNAs (lncRNA) are closely related to tumor proliferation, recurrence and metastasis. However, the exact mechanisms involving abnormally expressed lncRNA in hepatocellular carcinoma (HCC) remains unclear. We found that lncRNA HCAL identified by microarray from HCC patients were significantly upregulated and promoted cell proliferation and metastasis in HCC. Multiple epigenetic mechanisms may take part in HCAL-regulated HCC malignant phenotypes. We demonstrated the role of HCAL in growth and metastasis of HCC through integrating lncRNA, mRNA profiles with bioinformatics prediction, cell models, animal models and clinical samples data analyses. Combining with clinical information, we analyze the correlation between HCAL expression and HCC prognosis. By performing RIP, ChIP and RNA pull-down assays, we analyze the interaction of HCAL and other molecules including mRNA, miRNA and proteins, and illuminate the HCAL-regulated molecular network. All of these will help us reveal the key function of lncRNA in HCC, which may be of great importance for early diagnosis, treatment and prognosis prediction of HCC by using HCAL as a biological marker.

长链非编码RNA(lncRNA)与多种恶性肿瘤的增殖、复发及转移密切相关，但目前尚缺乏对肝细胞肝癌（HCC）中异常表达的lncRNA的完整认识。我们研究发现，通过芯片筛选出HCC中异常高表达的lncRNA HCAL能促进肝癌细胞的增殖和转移，多种表观遗传学机制可能共同参与HCAL调控的HCC恶性表型。本研究从已获得的lncRNA及mRNA表达谱等组学数据的整合性分析入手，结合生物信息学预测、细胞模型、动物模型及临床标本分析，阐明HCAL在HCC发生发展和转移中的作用；结合临床资料分析HCAL表达与预后的相关性；利用RIP、ChIP、RNA pull-down等关键技术分析HCAL对mRNA、miRNA、蛋白等其它分子的调控机制及规律，最终揭示HCC中HCAL的调控网络。这将有助于深入了解lncRNA在HCC中的作用机理，对以HCAL为靶点的HCC早期诊断、治疗及预后判断提供重要理论依据。

肝癌是全球最常见的恶性肿瘤之一。先前的研究证实LncRNAs在肝癌的发生和发展中起重要作用。在本项目中，我们鉴定了一条新的功能性的lncRNA，命名为HCAL。发现肝癌组织HCAL的表达水平显著高于癌旁组织，HCAL的表达与性别、肿瘤分化程度和血管癌栓相关。同时，HCAL的高表达预示肝癌病人的不良预后。体内外的功能实验结果显示，干扰HCAL表达，可以抑制肝癌细胞的增殖和转移能力。利用RNA测序的方法检测HCAL的下游基因，结果表明HCAL调控的基因主要富集在P53、肿瘤、MAPK、TGF-β等肿瘤相关通路。LAPTM4B是HCAL的下游靶基因，沉默HCAL能显著下调LAPTM4B表达。HCAL作为LAPTM4B的ceRNA，竞争结合miR-15a、miR-196a、miR-196b等microRNA，减少这些microRNA对LAPTM4B的结合，从而上调LAPTM4B的表达。因此，HCAL-LAPTM4B可能可以作为肝癌诊断和治疗的新型生物学靶标。