Diverse roles of UBE2T in cancer (Review)

Ubiquitin-conjugating enzyme E2T confers chemoresistance of colorectal cancer by enhancing the signal propagation of Wnt/β-catenin pathway in an ERK-dependent manner

Chemotherapy is a major therapeutic option for colorectal cancer; however, the frequently acquired chemoresistance greatly limits the treatment efficacy of chemotherapeutic agents. Ubiquitin-conjugating enzyme E2T (UBE2T) is emerging as a key player in the development of therapy resistance. However, whether UBE2T participates in the acquisition of chemoresistance in colorectal cancer remains undetermined. The present work aimed to specify the role of UBE2T in the development of chemoresistance in colorectal cancer and decipher any potential underlying mechanisms. Significant up-regulation of UBE2T was observed in the clinical specimens of chemoresistant colorectal cancer patients compared with chemosensitive patients. Compared with parental cells, the levels of UBE2T were also dramatically elevated in oxaliplatin (OXA)- and 5-fluorouracil (5-FU)-resistant colorectal cancer cells. Knockout of UBE2T rendered OXA- and 5-FU-resistant cells sensitive to OXA and 5-FU, respectively. Re-expression of UBE2T restored the chemoresistance of UBE2T-knockout OXA- and 5-FU-resistant cells. Mechanistically, phosphorylated GSK-3β, active β-catenin, c-myc and cyclin D1 levels were decreased in UBE2T-knockout OXA- and 5-FU-resistant cells, which were reversed by the re-expression of UBE2T. Moreover, knockout of UBE2T reduced the activation of ERK. The inhibition of ERK reversed the promotion effect of UBE2T on Wnt/β-catenin pathway. In vivo xenograft experiments demonstrated that knockout of UBE2T rendered the subcutaneous tumors formed by OXA-resistant cells sensitive to OXA. To conclude, UBE2T confers chemoresistance of colorectal cancer by boosting the signal propagation of the Wnt/β-catenin pathway in an ERK-dependent manner. Therefore, UBE2T could be a potential target for overcoming chemoresistance in the treatment of colorectal cancer.

UBE2T is a diagnostic and prognostic biomarker for endometrial cancer

BACKGROUND

Endometrial cancer (UCEC) is one of the most common malignant tumors in gynecology, and early diagnosis is crucial for its treatment. Currently, there is a lack of early screening tests specific to UCEC, and treatment advances are limited. It is crucial to identify more sensitive biomarkers for screening, diagnosis, and predicting UCEC. Previous studies have shown that UBE2T is involved in the development of various tumors such as breast cancer and liver cancer, but research on the role of UBE2T in UCEC is limited.

METHODS

Using data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and UALCAN databases, we analyzed the differential expression of UBE2T mRNA and protein in endometrial cancer (UCEC), along with its clinical relevance. A total of 113 clinical samples were collected, and immunohistochemistry and Western blot analysis were employed to validate bioinformatics analysis results. Volcano plots were generated using UBE2T and its differentially expressed genes, and a protein-protein interaction (PPI) network was constructed. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), gene set enrichment analysis (GSEA), and immune infiltration analysis were used to predict the functional role of UBE2T in UCEC progression. Correlation between UBE2T expression and patient survival was analyzed using TCGA data, and Kaplan-Meier survival curves were plotted.

RESULTS

UBE2T is significantly overexpressed in UCEC and correlates with poor prognosis. Its overexpression is closely associated with mitosis, cell cycle regulation, and histological grade in UCEC patients.

CONCLUSION

UBE2T is highly expressed in UCEC and suppresses anti-tumor immune responses in UCEC patients. It serves as a key participant in UCEC progression, associated with a range of adverse outcomes, and holds potential as a clinical diagnostic and prognostic biomarker.

Identification of small-molecule binding sites of a ubiquitin-conjugating enzyme-UBE2T through fragment-based screening

UBE2T is an attractive target for drug development due to its linkage with several types of cancers. However, the druggability of ubiquitin-conjugating E2 (UBE2T) is low because of the lack of a deep and hydrophobic pocket capable of forming strong binding interactions with drug-like small molecules. Here, we performed fragment screening using 19 F-nuclear magnetic resonance (NMR) and validated the hits with 1 H-15 N-heteronuclear single quantum coherence (HSQC) experiment and X-ray crystallographic studies. The cocrystal structures obtained revealed the binding modes of the hit fragments and allowed for the characterization of the fragment-binding sites. Further screening of structural analogues resulted in the identification of a compound series with inhibitory effect on UBE2T activity. Our current study has identified two new binding pockets in UBE2T, which will be useful for the development of small molecules to regulate the function of this protein. In addition, the compounds identified in this study can serve as chemical starting points for the development of UBE2T modulators.

Backbone 1H, 15N and 13C resonance assignments for an E2 ubiquitin conjugating enzyme-UBE2T

Ubiquitin-conjugating enzyme E2 T (UBE2T) plays important roles in ubiquitination of proteins through participation in transferring ubiquitin to its substrate. Due to its importance in protein modifications, UBE2T associates with diverse diseases and serves as an important target for drug discovery and development. The crystal structure of UBE2T has been determined and the structure reveals the lack of a druggable pocket for binding to small molecules for clinical applications. Despite the challenge, effort has been made to develop UBE2T inhibitors. We obtained UBE2T constructs with and without the C-terminal region which is flexible in solution. Herein, we report the backbone resonance assignments for human UBE2T without the C-terminal region. The backbone dynamics of UBE2T was also explored. The available assignments will be helpful for hit identification, determining ligand binding site and understanding the mechanism of action of UBE2T inhibitors.