Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma and is associated with a poor prognosis. Data from the Gene Expression Profiling Interactive Analysis (GEPIA) database revealed dysregulated expression of several ubiquitin-specific proteases (USPs) in DLBCL tissues (DLBCL vs. non-DLBCL = 47 vs. 337), including USP19 (log 2 fold change = 1.17, P < 0.05). USP19 is closely linked to tumorigenesis, but its role in DLBCL progression remains largely unknown. Here, we investigated the role of USP19 in DLBCL development. Genetic manipulation of USP19 using adenovirus-based vectors was performed in two DLBCL cell lines, SUDHL4 and DB cells. The results showed that USP19 knockdown suppressed the proliferation, anchorage-independent growth and xenograft tumor formation of DLBCL cells and arrested the cell cycle at the G1 stage. In parallel, DLBCL cells overexpressing USP19 acquired a more malignant phenotype. Next, to explore USP19 interactors, we performed co-immunoprecipitation/liquid chromatography–mass spectrometry and identified potential interacting proteins. Among them, Parkinson disease protein 7 (PARK7), a member of the peptidase C56 family known to be involved in carcinogenesis, was further validated to bind with and be stabilized by USP19. Additionally, we found that USP19 induced PARK7 deubiquitylation in both DLBCL cell lines, and PARK7 acted as a downstream effector of USP19 in regulating the growth of DLBCL cells. Collectively, USP19 exerts a tumor-promoting role in DLBCL through interacting with and stabilizing PARK7.
Xiaojing Xing,Meichen Liu,Xuguang Wang,Qianxue Guo,Hongyue Wang,Wenxue Wang
Diffuse large B-cell lymphoma (DLBCL) is difficult to treat due to the high recurrence rate and therapy intolerance, so finding potential therapeutic targets for DLBCL is critical. FK506-binding protein 3 (FKBP3) contributes to the progression of various cancers and is highly expressed in DLBCL, but the role of FKBP3 in DLBCL and its mechanism are not clear. Our study demonstrated that FKBP3 aggravated the proliferation and stemness of DLBCL cells, and tumour growth in a xenograft mouse model. The interaction between FKBP3 and parkinsonism associated deglycase (PARK7) in DB cells was found using co-immunoprecipitation assay. Knockdown of FKBP3 enhanced the degradation of PARK7 through increasing its ubiquitination modification. Forkhead Box O3 (FOXO3) belongs to the forkhead family of transcription factors and inhibits DLBCL, but the underlying mechanism has not been reported. We found that FOXO3 bound the promoter of FKBP3 and then suppressed its transcription, eventually weakening DLBCL. Mechanically, FKBP3 activated Wnt/β-catenin signalling pathway mediated by PARK7. Together, FKBP3 increased PARK7 and then facilitated the malignant phenotype of DLBCL through activating Wnt/β-catenin pathway. These results indicated that FKBP3 might be a potential therapeutic target for the treatment of DLBCL.
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