长链非编码RNA LncHPADR调控肝癌干细胞自我更新作用及其分子机制研究

Long noncoding RNAs (lncRNAs) have been implicated in the regulation of cellular development and pathogenesis. Research of lncRNAs has become the frontiers of the biological research field. In recent years, lncRNAs exert critical roles in tumorigenesis, however, little is known about the function and mechanism of lncRNAs in the regulation of self-renewal of cancer stem cells (CSCs). Through analyses of the whole transcriptome microarray and bioinformatics of liver CSCs from clinical hepatocellular carcinoma (HCC) samples, we have identified a bunch of lncRNAs that are involved in the self-renewal of liver cancer stem cells and liver tumorigenesis. We found a novel lncRNA termed lncRNA for Hand2 promoter-associated divergent noncoding RNA (lncHPADR)is highly expressed in the liver CSCs and is required in the self-renewal of liver CSCs and tumor propagation. lncHPADR recruits the Ino80 remodeling complex, leading to regulation of Wnt and Notch signaling. Hepatocyte specific lncHPADR, Ino80 and Ruvbl2 knockout mice have been establisehed. Mouse liver cancer model induced by diethylnitrosamine (DEN) were prepared. Based on our previous study, this project will further elucidate its regulatory roles, network, and mechanisms on the self-renewal of liver CSCs and the pathogenesis of liver cancer. Taken together, this study will systematically provide new insights into the critical roles and molecular mechanisms of lncHPADR in the regulation of self-renewal of liver CSCs and the tumorigenesis of liver cancer. Furthermore, this study will define lncHPADR as a novel effective target of live cancer therapy, and help to provide theoretical foundations for the diagnostic biomarkers and drug development of liver cancer.

长链非编码RNA（lncRNA）参与细胞发育与疾病发展等多种生命活动过程。近来发现，lncRNA在肿瘤发生发展中亦发挥着重要作用，但对肿瘤干细胞自我更新调控作用鲜有报道。本课题前期利用转录组芯片分析，发现并鉴定了一批与肝癌干细胞自我更新调控相关的lncRNA。其中，确定了新lncRNA lncHPADR在肝癌干细胞中高表达，且在肝癌干细胞干性维持中具有重要作用。还发现lncHPADR与Ino80重塑复合物相互作用，调节Wnt和Notch信号途径。成功制备了lncHPADR及其作用蛋白Ino80、Ruvbl2等基因条件敲除小鼠。在此基础上，本课题将深入探究lncHPADR对肝癌干细胞自我更新的调控作用及分子网络，揭示lncHPADR调控肝癌干细胞自我更新及肝癌发生的分子机制，从而明确lncHPADR作为肝癌干预新靶点的临床价值，为肝癌的诊断标志物和抗癌药物研发提供理论依据。

通过本项目的实施，项目组鉴定了肝癌干细胞差异表达的lncRNA，遴选了数条重要的lncRNA，探究它们对肝癌干细胞自我更新调控的作用及其分子机制，揭示了lncRNA作为肝癌干预新靶点的临床意义。主要成果总结如下：1、阐明了lncHand2调控肝脏再生的分子机制；2、揭示了HAND2-AS1激活BMP信号维持肝癌干细胞自我更新的分子机制；3、揭示了HAND2-AS1作为潜在肝癌干预新靶点的临床意义；4、揭示了lncBRM调控肝癌干细胞自我更新的分子机制； 5、阐明了LncHDAC2活化Hedgehog信号维持肝癌干细胞的自我更新的分子机制；6、还鉴定了肠道干细胞中的lncRNA，揭示了LncGATA6调控肠道干细胞干性维持的分子机制，发现LncGATA6能够促进肠癌发生，将有望成为肠癌干预的潜在新靶标。项目负责人在研究中做出了卓越的贡献，以通讯作者发表了高水平的研究论文21篇，包括Cell、J Heptol（2篇)、Nat Cell Biol、Nat Immunol、Immunity、Cell Research 、J Exp Med（2篇)、Nat Commun（6篇)等，相关成果申请了2项发明专利。项目负责人获得2019年获得基金委创新群体资助，2018年北京市科技进步一等奖。项目组培养了一批优秀的肿瘤研究才俊，2人获得基金委优秀青年基金资助，4人晋升为教授。综上，本研究得到了全面而深入的探索，完全实现了预期的研究目标。