HPVE6-USP46 Mediated Cdt2 Stabilization Reduces Set8 Mediated H4K20-Methylation to Induce Gene Expression Changes

Structure, Inhibitors, and Biological Function in Nervous System and Cancer of Ubiquitin-Specific Protease 46

Deubiquitinating enzymes (DUBs) prevent ubiquitination by eliminating ubiquitin from their substrates. Deubiquitinating enzymes have important roles in a number of cell biology subfields that are highly relevant to diseases like neurodegeneration, cancer, autoimmune disorders, and long-term inflammation. Deubiquitinating enzymes feature a well-defined active site and, for the most part, catalytic cysteine, which makes them appealing targets for small-molecule drug development. Ubiquitin-specific protease 46 (USP46) is a member of the ubiquitin-specific protease family, the largest subfamily of DUBs. Over the past 10 years, some studies have steadily demonstrated the significance of USP46 in several biological processes, although it was identified later and early research progress was modest. Specifically, in the last few years, the carcinogenic properties of USP46 have become more apparent. In the current review, we provide a comprehensive overview of the current knowledge about USP46 including its characteristics, structure, inhibitors, function in diseases, especially in the nervous system, and the correlation of USP46 with cancers.

Robotic-Assisted Surgery for Rectal Cancer: An Expedited Summary of the Clinical Evidence

Background

Rectal cancer is a disease in which cancer cells form in the rectum, which has the primary function of temporarily storing feces, controlling defecation, and maintaining continence. Surgery is the most common treatment for rectal cancer; surgical approaches include open, laparoscopic, and robotic assisted. We conducted an expedited summary of the clinical evidence for robotic-assisted surgery for rectal cancer, which included an evaluation of effectiveness and safety.

Methods

We performed a systematic literature search of the clinical evidence to retrieve systematic reviews and randomized controlled trials (RCTs). We assessed the risk of bias in the included systematic reviews using AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews, version 2), and we assessed the risk of bias in the included RCT using the Cochrane Risk-of-Bias Tool for Randomized Trials, version 1. We reported the quality of the body of evidence as evaluated in the included systematic reviews according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) Working Group criteria if it was evaluated.

Results

We included 14 studies in the clinical evidence review (12 systematic reviews and 1 RCT on robotic-assisted vs. laparoscopic rectal cancer surgery and 1 systematic review on robotic-assisted vs. open rectal cancer surgery). Compared with laparoscopic rectal cancer surgery, robotic-assisted rectal cancer surgery may result in similar overall survival; similar rates of conversion, blood transfusion, and readmission,· reduced blood loss; shorter length of stay; and improved quality of life. Compared with open rectal cancer surgery, robotic-assisted rectal cancer surgery may result in similar overall survival, reduced blood loss, and shorter length of stay.

Conclusions

Robotic-assisted rectal cancer surgery may result in similar or improved clinical outcomes compared with laparoscopic and open rectal cancer surgery.

USP46 enhances tamoxifen resistance in breast cancer cells by stabilizing PTBP1 to facilitate glycolysis

Tamoxifen (TAM) is the primary drug for treating estrogen receptor alpha-positive (ER+) breast cancer (BC). However, resistance to TAM can develop in some patients, limiting its therapeutic efficacy. The ubiquitin-specific protease (USP) family has been associated with the development, progression, and drug resistance of various cancers. To explore the role of USPs in TAM resistance in BC, we used qRT-PCR to compare USP expression between TAM-sensitive (MCF-7 and T47D) and TAM-resistant cells (MCF-7R and T47DR). We then modulated USP46 expression and examined its impact on cell proliferation, drug resistance (via CCK-8 and EdU experiments), glycolysis levels (using a glycolysis detection assay), protein interactions (confirmed by co-IP), and protein changes (analyzed through Western blotting). Our findings revealed that USP46 was significantly overexpressed in TAM-resistant BC cells, leading to the inhibition of the ubiquitin degradation of polypyrimidine tract-binding protein 1 (PTBP1). Overexpression of PTBP1 increased the PKM2/PKM1 ratio, promoted glycolysis, and intensified TAM resistance in BC cells. Knockdown of USP46 induced downregulation of PTBP1 protein by promoting its K48-linked ubiquitination, resulting in a decreased PKM2/PKM1 ratio, reduced glycolysis, and heightened TAM sensitivity in BC cells. In conclusion, this study highlights the critical role of the USP46/PTBP1/PKM2 axis in TAM resistance in BC. Targeted therapy against USP46 may represent a promising strategy to improve the prognosis of TAM-resistant patients.

Friend or foe? Reciprocal regulation between E3 ubiquitin ligases and deubiquitinases

Protein ubiquitination is a post-translational modification that entails the covalent attachment of the small protein ubiquitin (Ub), which acts as a signal to direct protein stability, localization, or interactions. The Ub code is written by a family of enzymes called E3 Ub ligases (∼600 members in humans), which can catalyze the transfer of either a single ubiquitin or the formation of a diverse array of polyubiquitin chains. This code can be edited or erased by a different set of enzymes termed deubiquitinases (DUBs; ∼100 members in humans). While enzymes from these distinct families have seemingly opposing activities, certain E3-DUB pairings can also synergize to regulate vital cellular processes like gene expression, autophagy, innate immunity, and cell proliferation. In this review, we highlight recent studies describing Ub ligase-DUB interactions and focus on their relationships.