课题组前期研究证实小分子A33可直接结合磷酸酶SHP2促进其降解，对结肠癌有很好的抑制作用。本项目拟针对A33诱导SHP2降解这一新作用方式展开研究，采用计算机模拟、表面等离子共振、肽段截短及点突变、圆二色谱等探讨A33结合并诱导SHP2蛋白降解的结构基础；采用免疫共沉淀及质谱鉴定A33作用下介导SHP2降解的E3泛素化连接酶及其可能的泛素化位点，并考察A33-SHP2-E3泛素化连接酶的相互作用过程；结合RNA测序等手段从细胞和动物水平探讨A33治疗结肠癌的药效并验证机制。在此基础上，比较结肠癌与癌旁组织中SHP2及介导其降解的E3泛素化连接酶的表达水平，进行二者与肿瘤患者的分期及PFS的相关性分析，确证结肠癌中SHP2高表达与其降解机制缺失的关系，进一步确证靶向降解SHP2在结肠癌治疗中的意义。本项目的实施预期阐明SHP2降解的新调控机制，为结肠癌等肿瘤的治疗提供新的策略和候选化合物。

Our previous research has proved that the small molecule A33 can directly bind to phosphatase SHP2 to promote its degradation, and has a good inhibitory effect on colon cancer. This project intends to investigate the new regulatory mechanism for SHP2 degradation, including : explore the structural basis for degradation of SHP2 by A33; identify the E3 ubiquitin ligase which mediate the SHP2 degradation under the action of A33 and its possible ubiquitination sites, further to examine the interaction process of A33-SHP2-E3 ubiquitination ligase ; explore the efficacy of A33 in the treatment of colon cancer and verify the related mechanisms in vitro and vivo by using RNA- seq and other techniques. On this basis, comparing expression of SHP2 and E3 ubiquitin ligase in the colorectal cancer clinical samples and tumor adjacent tissues, and analyzing their correlation with tumor stage and PFS, to confirm whether SHP2 is highly expressed in colon cancer and its relationship with the degradation mechanism, and further confirm the meanings of targeted degradation of SHP2 in the treatment of colon cancer. This project is expected to clarify the new regulatory mechanism of SHP2 degradation and provide new strategies and candidate compounds for the treatment of colon cancer.