Wu Qingsong, Qiu Yuanyuan, Guo Jinhui, Yuan Zibo, Yang Yingnan, Zhu Qingwei, Zhang Zhe, Guo Junwei, Wu Yanfang, Zhang Junyu, Huang Dongsheng, Tu Kangsheng, Hu Xiaoge
The Second Clinical Medical College of Zhejiang Chinese Medical University, Hangzhou, 310053, China.
The Key Laboratory of Tumor Molecular Diagnosis and Individualized Medicine of Zhejiang Province, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, 310014, China.
Biol Direct. 2024 Feb 2;19(1):13. doi: 10.1186/s13062-024-00456-3.
Hepatocellular carcinoma (HCC) is a prevalent malignant tumor that poses a major threat to people's lives and health. Previous studies have found that multiple deubiquitinating enzymes are involved in the pathogenesis of HCC. The purpose of this work was to elucidate the function and mechanism of the deubiquitinating enzyme USP40 in HCC progression.
The expression of USP40 in human HCC tissues and HCC cell lines was investigated using RT-qPCR, western blotting and immunohistochemistry (IHC). Both in vitro and in vivo experiments were conducted to determine the crucial role of USP40 in HCC progression. The interaction between USP40 and Claudin1 was identified by immunofluorescence, co-immunoprecipitation and ubiquitination assays.
We discovered that USP40 is elevated in HCC tissues and predicts poor prognosis in HCC patients. USP40 knockdown inhibits HCC cell proliferation, migration and stemness, whereas USP40 overexpression shows the opposite impact. Furthermore, we confirmed that Claudin1 is a downstream gene of USP40. Mechanistically, USP40 interacts with Claudin1 and inhibits its polyubiquitination to stabilize Claudin1 protein.
Our study reveals that USP40 enhances HCC malignant development by deubiquitinating and stabilizing Claudin1, suggesting that targeting USP40 may be a novel approach for HCC therapy.
肝细胞癌（HCC）是一种常见的恶性肿瘤，对人们的生命和健康构成重大威胁。先前的研究发现，多种去泛素化酶参与了HCC的发病机制。这项工作的目的是阐明去泛素化酶USP40在HCC进展中的功能和机制。
使用RT-qPCR、蛋白质印迹法和免疫组织化学（IHC）研究USP40在人HCC组织和HCC细胞系中的表达。进行了体外和体内实验，以确定USP40在HCC进展中的关键作用。通过免疫荧光、免疫共沉淀和泛素化测定法鉴定USP40与Claudin1之间的相互作用。
我们发现USP40在HCC组织中升高，并预示着HCC患者的预后不良。USP40敲低抑制HCC细胞增殖、迁移和干性，而USP40过表达则显示相反的影响。此外，我们证实Claudin1是USP40的下游基因。机制上，USP40与Claudin1相互作用并抑制其多聚泛素化以稳定Claudin1蛋白。
我们的研究表明，USP40通过去泛素化和稳定Claudin1增强HCC的恶性发展，这表明靶向USP40可能是一种新的HCC治疗方法。
