孤儿核受体LRH-1在肝癌中的功能及分子机制研究

Aim..The aim of this project is to identify the functions of the nuclear receptor LRH-1（liver receptor homolog-1）in hepatocellular carcinoma (HCC). ..Project Background..Nuclear receptors are a large superfamily transcriptional factors that function as ligand dependent or independent sensor molecules which not only regulate a broad range of physiological processes such as metabolism, development, reproduction, but also play various and significant roles in diseases, such as cancers. LRH-1 (liver receptor homolog-1), belongs to the fifth subfamily of nuclear receptor, is recently found to be involved in the development and progression of several cancers including colon cancer, breast cancer and pancreatic cancer. ..Brief Project Description..Existed gene-chip results indicate that LRH-1 shows higher expression level in HCC than that in normal tissue. Therefore, we speculate that LRH-1 may play a role in HCC. Base on this hypothesis, four HepG2LRH-1/- cell models with low LRH-1 expression are generated by genome editing mediated by Transcription Activator-Like Effector Nucleases (TALENs). According to sequencing results, at least five different mutations are detected in one HepG2LRH-1/- model which is from single cell clone. In addition, HepG2LRH-1/- cells grow significantly slower than HepG2. In this project, we will investigate the molecular mechanisms of LRH-1 in carcinogenesis of HCC. ..Significance of Project..Considering current treatment options for HCC are still limited and also mostly ineffective, the novel therapeutic targets and drugs are urgently needed. The present proposal will investigate the molecular mechanisms of LRH-1 in HCC. Given that LRH-1 specific antagonist is already developed, the outcomes from this project will provide new insights into the pathogenesis of HCC and explore a potential therapeutic target for HCC treatment.

最近研究表明孤儿核受体LRH-1参与多种癌症的发生。 但LRH-1是否同样影响肝癌的发生国内外未见报道。已有基因芯片数据证明LRH-1在肝癌组织中呈高表达，我们用Transcription Activator-Like Effector Nucleases (TALENs)介导的基因组编辑构建了下调LRH-1表达的HepG2细胞模型(HepG2LRH-1/-)并鉴定成功，测序结果显示在单一细胞来源的HepG2LRH-1/-细胞克隆中，至少检测到了5种不同的突变修复情况，提示LRH-1在肝癌细胞中可能存在基因组上拷贝数的扩增。另外HepG2LRH-1/-细胞的增殖速度明显低于正常HepG2细胞。我们推测LRH-1可能在肝癌组织中通过在基因组拷贝数的增加上调其表达水平并促进肝癌发生。本研究将利用HepG2LRH-1/-细胞模型为探索LRH-1作为肝癌治疗中潜在的药物靶点提供前期的科学依据。

背景：在肝癌的基础研究和临床治疗中，探索新型的治疗靶点一直以来都是最重要的研究领域。在以往的研究中，核受体LRH-1被证明在多种肿瘤的发生和发展过程中起着重要作用，包括乳腺癌，胰腺癌，结直肠癌症等等，但LRH-1在肝癌发生和发展过程中的分子机制至今仍不清楚。.方法：我们通过免疫组化的方法分析了LRH-1在肝癌临床标本中的表达情况；另外我们通过基因组编辑的方法构建了下调LRH-1表达的肝癌细胞模型，也构建了过表达LRH-1的肝癌细胞模型，然后通过体外和体内实验全面研究了LRH-1在肝癌中的分子机制。.结果：我们的结果证实LRH-1在肝癌临床组织中呈现高表达，通过体外和体内实验证实在肝癌细胞株HepG2中降低LRH-1的表达后能抑制其生长速率和成瘤能力。基因芯片结果表明LRH-1在肝癌细胞中主要调控细胞周期相关基因。另外，我们发现在肝癌细胞中过表达LRH-1可以促进c-myc, cyclin E1的表达，同时抑制p21的表达。.结论：我们的研究成果提示LRH-1可以作为肝癌治疗中的潜在靶点。