多功能Tudor-SN蛋白泛素化在肝细胞癌化疗敏感性中的作用机制

Reduction of hepatocellular carcinoma (HCC) chemosensitivity is a major cause of chemotherapy failure, which turns out to be a tough problem in clinical treatment of hepatocarcinoma. Stress Granules (SGs) are a type of cellular anti-apoptotic foci structure, which aggregate in response to environmental stress stimuli and are associated with the reduction of chemosensitivity. Previously, we found that Tudor-SN protein is ubiquitinated and modulates the SGs assembly, and knockdown of Tudor-SN enhances the sensitivity of HCC cells to chemotherapy drugs. Based on the above, this program aims at further investigating the role of stress protein Tudor-SN ubiquitination in the HCC chemosensitivity. We speculate that: After the stimulation of chemotherapy drugs, the K388, K389, K758 sites of Tudor-SN protein are ubiquitinated by E3 ubiquitin-protein ligase UHRF1; Then ubiquitinated Tudor-SN regulates the chemosensitivity via the SGs dependent or independent ways. Based on "drug-resistant HCC cell model" and "drug-resistant HCC in situ model", the crispr, FPLC, co-IP, MTS, Q-PCR, and other technologies will be used to verify our hypothesis, providing the theoretical basis for the reversal of HCC chemoresistance.

肝细胞癌（HCC）对化疗药物敏感性的降低是导致化疗失败的主要原因，为临床肝癌治疗的一大难题。应激颗粒（SGs）是细胞在受到外界刺激时形成的具有抗凋亡作用的颗粒结构，与化疗药物敏感性的降低相关。本课题组前期发现Tudor-SN蛋白可发生泛素化修饰，参与并调控SGs形成；沉默HCC细胞中的Tudor-SN能够增强其对化疗药物的敏感性。基于此，本项目旨在深入探讨应激颗粒蛋白Tudor-SN的泛素化在HCC化疗敏感性中的作用机制。推测：当HCC细胞受到化疗药物刺激时，E3酶UHRF1介导Tudor-SN蛋白K388、K389、K758位点发生泛素化修饰；泛素化的Tudor-SN通过SGs依赖或非依赖性途径降低对化疗药物的敏感性。本项目拟以“HCC细胞耐药模型”和“原位肝癌化疗耐药模型”为基础，利用crispr、FPLC、co-IP、MTS、Q-PCR等技术验证假设，为逆转肝癌治疗耐药提供理论依据。