BCAT2去泛素化修饰调控在胰腺癌中的作用及其分子机制

胰腺癌是一种恶性程度极高的肿瘤，5年存活率不超过8%。我们前期报道了BCAT2在胰腺癌早期PanIN导管中显著上调，并且靶向BCAT2治疗能有效阻断PanIN进程；KRAS突变通过调控BCAT2与E3泛素连接酶，上调其蛋白水平。最近我们通过筛选去泛素化酶库，发现USP1能显著上调BCAT2的蛋白水平；同时USP1的抑制剂ML323以剂量依赖式下调BCAT2的蛋白水平；进一步地，ML323处理显著增强BCAT2的泛素化梯子；更重要的是，我们通过数据库的分析，发现并验证了BCAT2的泛素化位点。以上实验结果提示靶向USP1的治疗能有效阻断BCAT2介导的胰腺癌发生发展。接下来，我们将采用分子生物学、生物化学和蛋白质组学等相关技术方法，从分子水平、细胞水平、类器官水平和动物水平，详细阐明去泛素化酶USP1调控BCAT2的分子机制及其功能，为临床胰腺癌的早期治疗提供有效靶点。

Pancreatic cancer is a highly malignant tumor with a 5-year survival rate of no more than 8%. Our previous work reported that BCAT2 was significantly upregulated in the early PanIN ducts of PDAC, and targeted BCAT2 treatment could effectively block the PanIN process; KRAS mutation regulates BCAT2 by the E3 ligase TRIM21 to up-regulate BCAT2 protein levels. Recently, we screened the deubiquitination enzyme library and found that ubiquitin-specific peptidase (USP1) significantly increased the protein level of BCAT2; meanwhile, USP1 inhibitor ML323 down-regulated the protein level of BCAT2 in a dose-dependent manner; furthermore, ML323 treatment dramatically enhanced the ubiquitination level of BCAT2; more importantly, through analysis of the phosphosite database, we identified the ubiquitination sites of BCAT2. These data suggest that USP1 targeted therapy can effectively block BCAT2-mediated PDAC development. Next, we will employee molecular biology, biochemistry and proteomics and other related technical methods to elaborate the molecular mechanism of USP1 to regulate BCAT2 from the molecular level, cell level, organoid level and animal level, and its molecular mechanism function, which will definitely provides effective targets for early treatment of clinical PDAC.