ABSTRACT
BACKGROUND:
Bladder cancer is the second most common genitourinary
malignancy worldwide. The
death rate of
bladder cancer has increased every year. However, the molecular mechanism of
bladder cancer is not sufficiently studied.
Deubiquitinating enzymes (DUBs)
play an important
role in
carcinogenesis. Several studies have demonstrated that USP5 associated with
malignancy and pathological progression in
hepatocellular carcinoma, colorectal and
non-small cell lung cancer. However, the
role of USP5 in
bladder cancer need to be explored.
METHODS:
The USP5 expression was analysed using the web server GEPIA. To explore USP5 function in
bladder cancer, we constructed USP5-knockout
cell lines in T24
cells. A FLAG-USP5 (WT USP5)
plasmid and a
plasmid FLAG-USP5 C335A (catalytic-inactive mutant) used to overexpress USP5 in EJ
cells. CCK8, colony formation, transwell and scratch 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 USP5 and c-Jun.
Cycloheximide (CHX) chase assays were performed to establish the effect of USP5 on c-Jun stability.
Xenograft mouse model was used to study the
role of USP5 in
bladder cancer.
RESULTS:
USP5 expression is increased in
bladder cancer patients. Genetic ablation of USP5 markedly inhibited
bladder cancer cell proliferation, viability, and migration both
in vitro and in vivo.
RNA-seq and
luciferase pathway
screening showed that USP5 activated JNK signalling, and we identified the interaction between USP5 and c-Jun. USP5 was found to activate c-Jun by inhibiting its
ubiquitination.
CONCLUSIONS:
Our results show that high USP5 expression promotes
bladder cancer progression by stabilizing c-Jun and that USP5 is a potential
therapeutic target in
bladder cancer.