TRIM31调控NLRP3炎性体参与肝癌进程的作用与分子机制

NLRP3 inflammasome is the key molecule and research hot point in innate immunity; however its role in tumor has not yet been clarified. The applicant discovered and reported for the first time the deregulation of NLRP3 inflammasome in hepatocarcinoma cells, and its expression level was negatively correlated with the clinical TNM stages and Edmonson grades, which indicated that its deregulation was involved in HCC progression. However, the molecular mechanism of its deregulation is not known, and the mechanisms involved in its contribution to HCC progression is not clarified. These two key scientific question will be explored in this project. Firstly we screened for the molecules that could regulate NLRP3, and we found that TRIM31, an E3 ligase was significantly upregulated in HCC cells and it could bind with NLRP3 and inhibit its expression. Based on our previous data and the research progression, we proposed to explore the mechanism involved in the negative regulation of NLRP3 by TRIM31, and clarified the key functional structure domain responsible for this negative regulation. We are going to focus on the TRIM31-NLRP3-mTOR axis in the HCC progression and its involved mechanism. This study may provide foundation for the elucidation of the mechanism of HCC progression, and provide basis for its targeted reversion of HCC development.

NLRP3炎性体是固有免疫领域的重要分子和研究热点，其在肿瘤中的作用尚未阐明。申请者前期在国际上首次发现并报道了NLRP3炎性体在肝癌细胞中表达显著下调，并且其表达水平与肝癌的TNM分期和病理Edmonson分级负相关，提示其表达失调参与了肝癌进程。但是NLRP3炎性体在肝癌细胞中表达失调的机制及其如何参与肝癌进程的机制尚不清楚，本项目中拟对此进行深入探讨。我们首先对能够调控NLRP3炎性体的分子进行了筛选，发现E3连接酶TRIM31在肝癌中显著上调，并且能与NLRP3结合并抑制其表达。结合我们的研究基础和该领域的前沿进展，我们拟在该项目中深入探索TRIM31负向调控NLRP3参与肝癌进程的作用，明确TRIM31调控NLRP3分子的关键结构域，并重点研究TRIM31-NLRP3 -mTOR轴在肝癌中的作用效应和机制。该研究将为阐明肝癌进展的分子机制和对其进行分子水平的靶向逆转奠定基础。

TRIM31是TRIM 家族的一个新成员，TRIM 分子能够参与细胞的多种生理及病理过程。该项目率先开展了TRIM31在肝细胞肝癌中的作用效应与分子机制。我们首先在临床标本中证实TRIM31在肝癌组织中的表达显著上调，其表达水平与肿瘤大小、临床分期、病理分级呈正相关，提示TRIM31的过表达参与了肝癌的进程。细胞实验和动物实验证实，TRIM31能够促进肝癌的恶性行为。靶点分析显示，TRIM31能够直接靶向NLRP3、TSC1、TSC2、p53等分子进行K-48位的泛素化降解。进一步靶点验证和功能实验显示，TRIM31直接靶向NLRP3炎症小体进行降解，参与机体对于固有免疫的调控效应；TRIM31直接靶向降解TSC1-TSC2复合体，并进一步发挥对mTORC1的负向调控效应，进而促进肝癌的进程；而TRIM31直接靶向p53进行泛素化降解，能够诱导肝癌细胞对于失巢凋亡的抵抗，并进一步促进肝癌的转移。在肝癌中的研究显示，TRIM31通过靶向TSC1-TSC2复合体进行K-48位泛素化降解，进而激活mTORC1信号通路，并促进肝癌的增殖和进展。在肝癌细胞中过表达TSC1-TSC2复合体能够有效逆转TRIM31的促癌效应，提示TRIM31的确是通过负向调控TSC1-TSC2复合体而发挥抑癌效应的。进一步的体内动物实验和临床标本检测证实了TRIM31对于TSC1-TSC2的负向调控效应。而对于NLRP3在肝癌中的作用效应和调控机制研究发现，NLRP3炎症小体在肝癌中表达显著下调，并与疾病的进展负相关，进一步的机制探讨发现NLRP3能够受到雌激素并经由其受体ERβ的正向调控，这能够部分解释肝癌发生中男女比例失调的问题。该研究为肝癌发生发展机制的阐明和对其进行早期干预奠定了基础，并为临床对于肝癌的分子靶向治疗提供了新的靶点，具有广阔的临床应用前景和开发价值。该项目的研究成果以第一标注发表了SCI收录论文6篇，其中发表在ONCOGENE的研究论文入选2018年ESI数据库引用前1%的“高被引论文”。该项目申报国家发明专利三项，获得山东省教育厅科研成果一等奖一项，山东医学科技成果二等奖一项。项目组多次参加国内外学术会议进行交流，引起了国内外同行的热烈讨论。