Background: Ubiquitination is an important post-transcriptional modification crucial for maintaining cell homeostasis. As a deubiquitination enzyme, ubiquitin-specific protease 1 (USP1) is associated with tumor progression; however, its role in bladder cancer is unknown. This study was aimed to analyze USP1 expression and study its roles in bladder cancer. Methods: The web server GEPIA was used to analyze the USP1 expression. To explore USP1 function in bladder cancer, we constructed USP1-knockout cell lines in UMUC3 cells. A FLAG-USP1 (WT USP1) plasmid and a plasmid FLAG-USP1 C90S (catalytic-inactive mutant) used to overexpress USP1 in T24 cells. CCK8, colony formation, and transwell assays were used to assess cell viability, proliferation and migration. RNA sequencing (RNA-seq) and dual-luciferase reporter assays were performed to screen the pathway. Coimmunoprecipitation and immunofluorescence were used to explore the interaction between USP1 and c-MYC. Xenograft mouse model was used to study the role of USP1 in bladder cancer. Results: USP1 expression is upregulated in human bladder cancer cells and correlated with poor patient prognosis. USP1 overexpression promoted cell proliferation, clone formation, and migration; this was attenuated by genetic ablation of USP1. Furthermore, we observed that USP1- deficiency inhibited tumor formation in vivo. Mechanistically, the c-MYC pathway was remarkably activated compared with the other pathways. Furthermore, USP1 could directly interact with c-MYC. and increase c-MYC stability depending on the catalytic activity of USP1. Conclusions: Our results suggest that high expression of USP1 promotes bladder cancer progression by stabilizing c-MYC; hence, USP1 it may serve as a novel therapeutic target for treating bladder cancer.

The effects of environmental media on the corrosion fatigue fracture behavior of 25CrMo steel were investigated. The media include air, and a 3.5 wt.% and a 5.0 wt.% NaCl solutions. Experimental results indicate that the media induces the initiation of corrosion fatigue cracks at multiple sites. The multi-cracking sites cause the changes in the crack growth directions, the crack growth rate during the coupling action of the media and the stress amplitude. The coupling effects are important for engineering applications and research. The probability and predictions of the corrosion fatigue characteristic life can be estimated using the 3-parameter Weibull distribution function.