sCLU调控Wnt/β-catenin通路促进肝癌干细胞样特性的机制研究

Secretory clusterin (sCLU) is reported to be involved in the recurrence and chemoresistance of hepatocellular carcinoma (HCC). However, the underlying molecular mechanism remains largely elusive. In preliminary work, we found that sCLU was overexpressed in cancer stem cells (CSCs)-like HCC cells. Moreover, repression of sCLU could inhibit CSCs-like properties mediated by β-catenin and alter phosphorylation levels of GSK-3β and β-catenin in HCC. Accordingly, we hypothesize that sCLU may activate Wnt/β-catenin pathway via regulation phosphorylation of GSK-3β, which promotes CSCs-like properties of HCC cells. We aim to conduct the project as follows. First, clinical samples are adopted to analyze the expressions of sCLU, pGSK-3β, β-catenin and CSCs-related genes in HCC tissues, and to verify the correlation of them with recurrence and chemoresistance. Then we will explore the regulation mechanisms of sCLU in Wnt/β-catenin pathway and its impact on CSCs-like properties of HCC. Finally, we investigate the correlations among sCLU, Wnt/β-catenin pathway and CSCs-like properties in the xenografted model. Our study may help clarify the molecular mechanism of sCLU in CSCs-like properties mediated by Wnt/β-catenin pathway in HCC, and provide a new theoretical basis for the therapy of HCC.

分泌型丛生蛋白(sCLU)在肝癌复发和耐药中发挥了重要作用。课题组前期研究发现sCLU在肿瘤干细胞(CSCs)样肝癌细胞中高表达，敲降sCLU能抑制β-catenin介导的肝癌干细胞样特性，并影响β-catenin及GSK-3β磷酸化水平。基于此，我们提出sCLU通过调节GSK-3β磷酸化水平，激活Wnt/β-catenin通路，从而促进肝癌干细胞样特性的假说。本项目拟完成：临床标本分析肝癌组织中sCLU、pGSK-3β、β-catenin及CSCs标志物的表达相关性及与复发和耐药的关系；细胞水平探究sCLU调控Wnt/β-catenin通路的具体机制及对肝癌干细胞样特性的影响；移植瘤模型验证sCLU与Wnt/β-catenin通路及肝癌干细胞样特性的关系。本研究将阐明sCLU调控Wnt/β-catenin通路促进肝癌干细胞样特性的分子机制，为肝癌的治疗提供新的理论依据。

肝癌是一种多中心多阶段的难治性恶性肿瘤，常伴有多药耐药和转移复发。肿瘤干细胞(CSCs)已被认为是肿瘤细胞恶性表型的关键因素，寻找特异分子靶向肿瘤干细胞对于肝癌治疗具有重要意义。前期研究显示，分泌型丛生蛋白(sCLU)可促进肝癌复发和耐药，在肿瘤干细胞样肝癌细胞中高表达，并和肿瘤干性特征相关。本研究从多个层面揭示了sCLU对Wnt/β-catenin通路介导的肝癌干细胞样特性的调控作用及机制。在细胞层面，肝癌细胞株中敲低或过表达sCLU可明显抑制或促进肝癌细胞恶性生物学行为及肿瘤干细胞样特性；进一步功能挽救和机制挽救实验发现，sCLU通过上调GSK-3β磷酸化水平抑制GSK-3β活性，提高β-catenin累积，从而激活AKT/GSK-3β/β-catenin信号轴强化肝癌细胞肿瘤干细胞样特性。动物层面，通过构建裸鼠移植瘤模型，发现sCLU可明显促进肝癌细胞体内成瘤，并和β-catenin表达呈正相关。类器官层面，sCLU反义药物OGX-011可明显促进肝癌类器官对索拉菲尼的敏感性，并可显著下调CSCs标志物表达水平。临床样本层面，免疫组化显示肝癌组织中sCLU与β-catenin表达水平呈正相关，二者共表达是一个独立的肝癌预后因素。本研究从体内、体外多个维度探讨sCLU通过Wnt/β-catenin相关信号调控肝癌干细胞样特性的机制，为肝癌治疗提供了潜在的分子靶点。