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USP7 通过 RSK4/PI3K/AKT 轴介导 TRAF4 的去泛素化，促进卵巢癌细胞的恶性表型。

USP7 mediates TRAF4 deubiquitination to facilitate the malignant phenotype of ovarian cancer via the RSK4/PI3K/AKT axis.

机构信息

Department of the Central Laboratory; Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha 410013, Hunan Province, P.R. China.

Department of the Central Laboratory, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha 410013, Hunan Province, P.R. China.

出版信息

J Cancer Res Ther. 2023 Feb;19(1):97-107. doi: 10.4103/jcrt.jcrt_517_22.

DOI:10.4103/jcrt.jcrt_517_22

PMID:37006049

Abstract

BACKGROUND

Ubiquitin-specific peptidase 7 (USP7) is upregulated in multiple human cancers, including ovarian cancer; however, its functional role in the latter remains largely unknown.

METHODS

We conducted quantitative real-time PCR to detect the expression of USP7, TRAF4, and RSK4 in ovarian cancer cell lines. In addition, Western blotting served to determine USP7, TRAF4, RSK4, PI3K, and AKT (protein kinase B,PKB) protein levels and USP7 expression in the tissues was detected by immunohistochemical staining. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was used to evaluate cell viability, transwell assays to evaluate cell migration and invasion, and co-immunoprecipitation to evaluate TRAF4 ubiquitination.

RESULTS

The results showed USP7 and TRAF4 upregulation, and RSK4 downregulation in ovarian cancer cell lines. Knocking down USP7 suppressed viability, migration, and invasion of ovarian cancer cells; TRAF4 knockdown and RSK4 overexpression had similar effects in ovarian cancer cells. TRAF4 is deubiquitinated and stabilized by USP7, whereas RSK4 is negatively regulated by TRAF4. A mouse xenograft model confirmed that knocking down USP7 suppressed ovarian tumor growth by regulating the TRAF4/RSK4/PI3K/AKT axis.

CONCLUSION

Knocking down USP7 decreased the proliferation, migration, and invasion of ovarian cancer cells and suppressed ovarian tumor growth in mice. Mechanistically, USP7 increased TRAF4 ubiquitination, promoting its degradation and leading to RSK4 upregulation.

摘要

背景

泛素特异性肽酶 7（USP7）在多种人类癌症中上调，包括卵巢癌；然而，其在后者中的功能作用在很大程度上仍然未知。

方法

我们通过定量实时 PCR 检测了卵巢癌细胞系中 USP7、TRAF4 和 RSK4 的表达。此外，Western blot 用于确定 USP7、TRAF4、RSK4、PI3K 和 AKT（蛋白激酶 B，PKB）蛋白水平，免疫组织化学染色检测组织中 USP7 的表达。3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide，MTT）检测细胞活力，Transwell 检测细胞迁移和侵袭，免疫共沉淀检测 TRAF4 泛素化。

结果

结果显示，USP7 和 TRAF4 在卵巢癌细胞系中上调，RSK4 下调。敲低 USP7 抑制了卵巢癌细胞的活力、迁移和侵袭；TRAF4 敲低和 RSK4 过表达在卵巢癌细胞中也有类似的作用。USP7 使 TRAF4 去泛素化并稳定，而 RSK4 受 TRAF4 负调控。在小鼠异种移植模型中证实，通过调节 TRAF4/RSK4/PI3K/AKT 轴，敲低 USP7 抑制了卵巢肿瘤的生长。