HUWE1介导的自噬调控多药耐药肝癌细胞耐药性的机制研究

Autophagy is closely related to the multidrug-resistance of tumor cells.It is of great significance for reversing drug-resistance of tumor cells on clinical by inhibiting autophagy in the multidrug-resistance tumor cells. Suppression of apoptosis mediated by HUWE1, a BH3-only E3 ubiquitin ligase, contributes to multidrug-resistance in tumor cells. Our recent advances showed that there are negative correlation between expression of HUWE1 and increasing autophagic activity or degree of multidrug resistance, and expression of HUWE1 decreases by inducing autophagy. The bottom line is that HUWE1 interacts with an important autophagic regulator ---Beclin-Vps34. Therefore, we propose that HUWE1 may be an negative factor to regulate autophagic process. And probably, some regulators down-regulated expression of HUWE1 is the reason that increase of autophagic activity induces multidrug resisitance. Present project will take the multidrug-resistant HCC cells as target cells and investigate the following : (1) the mechanism of autophagy modulated by HUWE1; (2) finding out the difference in regulators of HUWE1 between multidrug resistant cells and sensitive cells, and exploring the mechanism of multidrug resistance mediated by activation of autophagy. This project is to provide some new experimental evidences for deeply understanding the mechano-biological mechanism of multidrug resistance caused by autophagy, and some efficacious therapy for reversing multidrug resistance in tumor cells on clinical.

自噬激活导致肿瘤细胞多药耐药性的产生，抑制自噬已成为临床治疗耐药性肿瘤、增敏肿瘤细胞对抗肿瘤介质敏感性的有效手段。HUWE1是仅含有BH3结构域的E3泛素连接酶，它在耐药细胞中表达水平下调，引起细胞凋亡抑制导致肿瘤细胞耐药性的产生。申请者研究发现：HUWE1与耐药细胞高水平的自噬活性和耐药性呈负相关；激活自噬，HUWE1水平下调，并与自噬调节复合物Beclin1-Vps34相互作用。因此提出：HUWE1可能通过调控Beclin1-Vps34抑制自噬活性；影响HUWE1自身水平下调的因素可能是导致自噬活性升高、引起细胞耐药的分子机制。本项目拟以肝癌耐药细胞为靶细胞：研究HUWE1参与细胞自噬调节的机制；通过比较耐药细胞和敏感细胞中HUWE1上游调控分子的差异，寻找其激活自噬致使细胞耐药的分子机制。为深入了解自噬调控影响细胞耐药性提供理论基础，并为抑制自噬逆转肿瘤细胞耐药性提供有效治疗靶点。

自噬激活导致肿瘤细胞多药耐药性的产生，抑制自噬已成为临床治疗耐药性肿瘤、增敏肿瘤细胞对抗肿瘤介质敏感性的有效手段。HUWE1是仅含有BH3结构域的E3泛素连接酶，它在耐药细胞中表达水平下调，引起细胞凋亡抑制导致肿瘤细胞耐药性的产生。本课题研究发现：HUWE1与耐药细胞高水平的自噬活性和耐药性呈负相关；HUWE1靶向自噬关键蛋白Beclin1的泛素化降解；体内研究发现敲除HUWE1可通过激活自噬引起细胞对常规化疗药物的抵抗性。通过免疫共沉淀和质谱技术寻找出了HUWE1上游调控分子CUL4B，发现了HUWE1下调激活自噬致使细胞耐药的分子机制。为深入了解自噬调控影响细胞耐药性提供理论基础，并为抑制自噬逆转肿瘤细胞耐药性提供有效治疗靶点。