Oncogene database

23326

USP22

ubiquitin specific peptidase 22;USP22;ubiquitin specific peptidase 22

deubiquitinating enzyme 22|ubiquitin carboxyl-terminal hydrolase 22|ubiquitin specific protease 22|ubiquitin thioesterase 22|ubiquitin thiolesterase 22|ubiquitin-specific processing protease 22|ubiquitin-specific-processing protease 22

17p11.2

protein-coding

Recent studies provided strong support for the view that ubiquitin-specific protease 22 (USP22) plays a central role in cell-cycle progression and also in pathological processes such as oncogenesis. We have recently shown that USP22 levels are elevated in colorectal carcinoma with associated increase in the expression of several cell-cycle-related genes. However, the precise mechanism for these functions of USP22 at molecular level has not been fully elucidated. Currently, we investigated the role of USP22 in human colorectal cancer (CRC). We observed that USP22 expression was statistically significantly correlated positively with that of BMI-1, c-Myc and both, pAkt (Ser473), and pAkt (Thr308), in primary tumor tissues from 43 CRC patients. Down-regulation of USP22 expression in HCT116 colorectal cancer cells by siRNA resulted in the accumulation of cells in the G1 phase of the cell cycle. RNAi-knockdown of USP22 in HCT16 cells also led to the repression of BMI-1 and was accompanied by the up-regulation of p16INK4a and p14ARF, with a consequent decrease in E2F1 and p53 levels. In addition, down-regulation of c-Myc-targeted cyclin D2 was also noticed in cells treated with USP22-siRNA. Furthermore, our results showed that USP22 deletion also caused down-regulation of Akt/GSK3beta activity, which can also contribute to the reduction of cyclin D2. Collectively, our current results suggest that USP22 may act as an oncogene in CRC as it positively regulates cell cycle via both BMI-1-mediated INK4a/ARF pathway and Akt signaling pathway.

Ubiquitin-specific protease 22 (USP22), a novel deubiquitinating enzyme, has been associated with metastasis, therapy resistance, and cell cycle progression. The purpose of this study was to investigate the expression level of USP22 in papillary thyroid carcinoma (PTC) samples and to evaluate its clinical significance in PTC patients. USP22 expression was examined in 30 fresh PTC tissues and paired adjacent noncancerous tissues by real-time quantitative RT-PCR. Immunohistochemistry for USP22 was performed on additional 156 PTC tissues. The clinical significance of USP22 expression was analyzed. We found that the expression levels of USP22 mRNA and protein in PTC tissues were both significantly higher than those in noncancerous tissues. Clinicopathological analysis showed that USP22 expression was significantly correlated with tumor size (p=0.036), extracapsular invasion (p=0.012), multifocality (p=0.014), lymph node metastasis (p=0.022), distant metastasis (p=0.005), and TNM stage (p=0.002). The Kaplan-Meier survival curves revealed that USP22 expression was associated with poor prognosis in PTC patients. USP22 expression was an independent prognostic marker of overall patient survival in a multivariate analysis. Our findings suggest that USP22 is an independent predictor of poor prognosis of PTC patients.

Increasing evidence links deregulation of the ubiquitin-specific proteases 22 (USP22) deubitiquitylase to cancer development and progression in a select group of tumor types, but its specificity and underlying mechanisms of action are not well defined. Here we show that USP22 is a critical promoter of lethal tumor phenotypes that acts by modulating nuclear receptor and oncogenic signaling. In multiple xenograft models of human cancer, modeling of tumor-associated USP22 deregulation demonstrated that USP22 controls androgen receptor accumulation and signaling, and that it enhances expression of critical target genes coregulated by androgen receptor and MYC. USP22 not only reprogrammed androgen receptor function, but was sufficient to induce the transition to therapeutic resistance. Notably, in vivo depletion experiments revealed that USP22 is critical to maintain phenotypes associated with end-stage disease. This was a significant finding given clinical evidence that USP22 is highly deregulated in tumors, which have achieved therapeutic resistance. Taken together, our findings define USP22 as a critical effector of tumor progression, which drives lethal phenotypes, rationalizing this enzyme as an appealing therapeutic target to treat advanced disease.

The histone ubiquitin hydrolase ubiquitin-specific protease 22 (USP22) is an epigenetic modifier and an oncogene that is upregulated in many types of cancer. In non-small cell lung cancer (NSCLC), aberrant expression of USP22 is a predictor of poor survival, as is high expression of cyclooxygenase-2 (COX-2). Despite its oncogenic role, few substrates of USP22 have been identified and its mechanism of action in cancer remains unclear. Here, we identified COX-2 as a direct substrate of USP22 and showed that its levels are modulated by USP22 mediated deubiquitination. Silencing of USP22 downregulated COX-2, decreased its half-life, and inhibited lung carcinoma cell proliferation by directly interacting with and modulating the stability and activity of COX-2 through the regulation of its ubiquitination status. The findings of the present study suggest a potential mechanism underlying the oncogenic role of USP22 mediated by the modulation of the stability and activity of COX-2.