甲状腺素受体在肝细胞肝癌转移过程中的作用及机制研究

The depth of tumor invasion, metastasis, and postoperative relapse are universal and continues to be the main cause of late deaths in patients with hepatocellular carcinoma (HCC). Epithelial-mesenchymal transition (EMT) is closely associated with frequent postoperative recurrence and poor survival in patients with HCC.Thyroid hormone (TH) combined with thyroid hormone receptor (TR) play a important role in the process of cell growth, proliferation and differentiation. Studies showed that over activated of TR promoted tumorigenesis and metastasis in various cancer. Signaling pathways have been implicated in EMT regulating important processes during the development of HCC including Wnt/β-catenin and TH/TR signaling pathway. Our previous work suggested that G-protein coupled receptor 5 (LGR5) playing an important role in metabolic regulation and signal transduction processes within cells, which could promote EMT and enhance HCC recurrence. At the same time, we found that there was some correlation among TR, LGR5 and EMT-related genes by using TR knock out animal models. Here, we will.explore the possible mechanisms underlying the regulation of LGR5 expression by TH/TR, and the function of TR in hepatocarcinogenesis and metastasis from molecular level, cellular level and organization level. In a word, we try to clarify the function and molecular mechanism of TR in hepatocarcinogenesis and metastasis and provide a new target site for the treatment and prevention of HCC.

肝细胞肝癌（HCC）的术后复发和转移是患者死亡的重要原因，上皮间质转化（EMT）与其密切相关。甲状腺激素（TH）具有多种调控功能，通过与甲状腺素受体（TR）结合，调控细胞的生长、增殖、分化等过程。有研究表明，TR的过度激活与多种肿瘤的发生和侵袭有关。肿瘤细胞的EMT过程由多个信号通路共同参与介导，其中Wnt/β-catenin通路和TH/TR通路尤为引人关注。我们前期研究发现，在HCC中G-蛋白偶联受体5(LGR5)在细胞信号转导和代谢调节等方面有着重要作用，LGR5的高表达通过激活Wnt/β-catenin通路促进肝癌细胞的EMT过程。与此同时，利用TR基因敲除动物模型，我们发现TR与LGR5和EMT相关基因存在相关性。进一步我们拟通过分子生物学手段和小鼠荷瘤模型阐明TH/TR通路在调控LGR5及HCC发生和转移过程中的作用机制，为治疗和预防HCC术后复发提供新的靶点和理论依据。

背景：肝细胞癌（HCC）是世界上导致癌症相关死亡的主要原因之一。最近的研究表明，环状RNA（circRNA）在组织发育、基因转录、信号调控和肿瘤发生等方面发挥着重要作用。然而circRNA是否参与HCC的进展和编码功能蛋白仍然是未知的。.方法：选取3对肝癌组织和对应的癌旁组织进行circRNA基因芯片检测。应用细胞迁移实验，划痕实验和流式细胞术检测细胞circRNA过度表达后对肝癌细胞侵袭，迁移，周期和细胞凋亡的影响。将带有标志标记的circEPS15的全长、突变和截断序列插入到循环表达式载体中。Western blotting用于确认circEPS15的表达和circRNA内部核糖体进入位点（IRES）元素的位置。通过分析从肿瘤基因组图谱（TCGA）数据库检索到的数据，获得miRNA和mRNA的表达谱。然后我们构建了一个由circeps15、miRNAs和mRNAs组成的ceRNA网络。.结果：肝癌组织中circEPS15表达水平下降，且与较短的生存期相关。过度表达circEPS15通过抑制TJP1/CDH2/VIM信号通路抑制肿瘤侵袭和迁移，延缓细胞周期进程，但对细胞凋亡无影响。ceRNA分析和qRT-PCR结果提示HCC可能存在circRNA（circEPS15）-miRNA（miR-24-3p）-mRNA（CIDEA）网络。IRES驱动的跨越结开放阅读框编码了一种新的蛋白质。.结论：内源性circEPS15通过ceRNA网络和编码一种功能蛋白在抑制HCC中发挥了新的作用。