UBE2T promotes proliferation via G2/M checkpoint in hepatocellular carcinoma

The role of ubiquitin-conjugating enzyme in the process of spermatogenesis

The ubiquitination is crucial for controlling cellular homeostasis and protein modification, in which ubiquitin-conjugating enzyme (E2) acts as the central player in the ubiquitination system. Ubiquitin-conjugating enzymes, which have special domains that catalyse substrates, have sequence discrepancies and modulate various pathophysiological processes in different cells of multiple organisms. E2s take part in the mitosis of primordial germ cells, meiosis of spermatocytes and the formation of mature haploid spermatids to maintain normal male fertility. In this review, we summarize the various types of E2s and their functions during distinct stages of spermatogenesis.

Finding key genes (UBE2T, KIF4A, CDCA3, and CDCA5) co-expressed in hepatitis, cirrhosis and hepatocellular carcinoma based on multiple bioinformatics techniques

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Hepatitis B virus (HBV) is one of the major causes of liver cirrhosis (LC) and HCC. Therefore, the discovery of common markers for hepatitis B or LC and HCC is crucial for the prevention of HCC.

METHODS

Expressed genes for to chronic active hepaititis B (CAH-B), LC and HCC were obtained from the GEO and TCGA databases, and co-expressed genes were screened using Protein-protein interaction (PPI) networks, least absolute shrinkage and selection operator (LASSO), random forest (RF) and support vector machine - recursive feature elimination (SVM-RFE). The prognostic value of genes was assessed using Kaplan-Meier (KM) survival curves. Columnar line plots, calibration curves and receiver operating characteristic (ROC) curves of individual genes were used for evaluation. Validation was performed using GEO datasets. The association of these key genes with HCC clinical features was explored using the UALCAN database ( https://ualcan.path.uab.edu/index.html ).

RESULTS

Based on WGCNA analysis and TCGA database, the co-expressed genes (565) were screened. Moreover, the five algorithms of MCODE (ClusteringCoefficient, MCC, Degree, MNC, and DMNC) was used to select one of the most important and most closely linked clusters (the top 50 genes ranked). Using, LASSO regression model, RF model and SVM-RFE model, four key genes (UBE2T, KIF4A, CDCA3, and CDCA5) were identified for subsequent research analysis. These 4 genes were highly expressed and associated with poor prognosis and clinical features in HCC patients.

CONCLUSION

These four key genes (UBE2T, KIF4A, CDCA3, and CDCA5) may be common biomarkers for CAH-B and HCC or LC and HCC, promising to advance our understanding of the molecular basis of CAH-B/LC/HCC progression.

The role of abnormal ubiquitination in hepatocellular carcinoma pathology

Primary liver cancer is known for its high incidence and fatality rate. Over the years, therapeutic strategies for primary liver cancer have advanced significantly. Nonetheless, a substantial number of patients have not benefited from these methods, underscoring the pressing need for new and effective treatments for primary liver cancer. Ubiquitination is a critical post-translational modification that enables proteins to fulfill their normal biological functions and maintain their expression stability within cells. Importantly, increasing evidence suggests that the progression of liver cancer cells is often accompanied by disruptions in protein ubiquitination and deubiquitination processes. In this comprehensive review, we have compiled pertinent research about dysregulated ubiquitination in hepatocellular carcinoma (HCC) to broaden our understanding in this field. We elucidate the connections between the ubiquitination proteasome system, deubiquitination, and HCC. Furthermore, we shed light on the role of ubiquitination in cells situated within the tumor microenvironment of HCC including its involvement in mediating the activation of oncogenic pathways, reprogramming metabolic processes, and perturbing normal cellular functions. In conclusion, targeting the dysregulation of ubiquitination in HCC holds promise as a prospective and complementary therapeutic approach to existing treatments.

CircNUP50 is a novel therapeutic target that promotes cisplatin resistance in ovarian cancer by modulating p53 ubiquitination

BACKGROUND

Most patients with ovarian cancer (OC) treated with platinum-based chemotherapy have a dismal prognosis owing to drug resistance. However, the regulatory mechanisms of circular RNA (circRNA) and p53 ubiquitination are unknown in platinum-resistant OC. We aimed to identify circRNAs associated with platinum-resistant OC to develop a novel treatment strategy.

METHODS

Platinum-resistant circRNAs were screened through circRNA sequencing and validated using quantitative reverse-transcription PCR in OC cells and tissues. The characteristics of circNUP50 were analysed using Sanger sequencing, oligo (dT) primers, ribonuclease R and fluorescence in situ hybridisation assays. Functional experimental studies were performed in vitro and in vivo. The mechanism underlying circNUP50-mediated P53 ubiquitination was investigated through circRNA pull-down analysis and mass spectrometry, luciferase reporters, RNA binding protein immunoprecipitation, immunofluorescence assays, cycloheximide chase assays, and ubiquitination experiments. Finally, a platinum and si-circNUP50 co-delivery nanosystem (Psc@DPP) was constructed to treat platinum-resistant OC in an orthotopic animal model.

RESULTS

We found that circNUP50 contributes to platinum-resistant conditions in OC by promoting cell proliferation, affecting the cell cycle, and reducing apoptosis. The si-circNUP50 mRNA sequencing and circRNA pull-down analysis showed that circNUP50 mediates platinum resistance in OC by binding p53 and UBE2T, accelerating p53 ubiquitination. By contrast, miRNA sequencing and circRNA pull-down experiments indicated that circNUP50 could serve as a sponge for miR-197-3p, thereby upregulating G3BP1 to mediate p53 ubiquitination, promoting OC platinum resistance. Psc@DPP effectively overcame platinum resistance in an OC tumour model and provided a novel idea for treating platinum-resistant OC using si-circNUP50.

CONCLUSIONS

This study reveals a novel molecular mechanism by which circNUP50 mediates platinum resistance in OC by modulating p53 ubiquitination and provides new insights for developing effective therapeutic strategies for platinum resistance in OC.

Hepatocellular Carcinoma: Up-regulated Circular RNAs Which Mediate Efficacy in Preclinical In Vivo Models

Hepatocellular carcinoma (HCC) ranges as number two with respect to the incidence of tumors and is associated with a dismal prognosis. The therapeutic efficacy of approved multi-tyrosine kinase inhibitors and checkpoint inhibitors is modest. Therefore, the identification of new therapeutic targets and entities is of paramount importance. We searched the literature for up-regulated circular RNAs (circRNAs) which mediate efficacy in preclinical in vivo models of HCC. Our search resulted in 14 circRNAs which up-regulate plasma membrane transmembrane receptors, while 5 circRNAs induced secreted proteins. Two circRNAs facilitated replication of Hepatitis B or C viruses. Three circRNAs up-regulated high mobility group proteins. Six circRNAs regulated components of the ubiquitin system. Seven circRNAs induced GTPases of the family of ras-associated binding proteins (RABs). Three circRNAs induced redox-related proteins, eight of them up-regulated metabolic enzymes and nine circRNAs induced signaling-related proteins. The identified circRNAs up-regulate the corresponding targets by sponging microRNAs. Identified circRNAs and their targets have to be validated by standard criteria of preclinical drug development. Identified targets can potentially be inhibited by small molecules or antibody-based moieties and circRNAs can be inhibited by small-interfering RNAs (siRNAs) or short hairpin RNAs (shRNAs) for therapeutic purposes.

Genome-wide identification and transcriptome-based expression profiling of E2 gene family: Implication for potential roles in gonad development of Crassostrea gigas

In this study, we investigated the role of E2 ubiquitin conjugating enzymes (E2) in the Pacific oyster Crassostrea gigas, with a focus on their involvement in gonad development. We identified 34 E2 genes clustered into nine subgroups and 24 subfamilies. The gene structure and intron-exon location were conserved within the same subfamily, but motif variation suggested functional diversity. Tissue transcriptome analyses revealed that most E2 genes were broadly expressed, with UBE2CL showing specific expression in the female gonad. Expression profiling of E2 genes during early embryo-larvae development stages suggested that five E2 genes were highly expressed in early embryo development, indicating their involvement in cell division processes. Furthermore, by profiling the expression of E2 genes in different gonadal developmental stages, we observed a gradual increase in expression for four genes during gametogenesis, with significantly higher expression in the female gonad at the maturation stage. Similarly, five E2 genes displayed elevated expression levels in the male gonad at the maturation stage, indicating their crucial roles in gonadal development and gametogenesis. Our study provides valuable insights into the potential functions of the E2 gene family in C. gigas, shedding light on the molecular mechanisms underlying gonad development in oysters.

Diverse roles of UBE2T in cancer (Review)

As a leading cause of mortalities worldwide, cancer results from accumulation of both genetic and epigenetic alterations. Disruption of epigenetic regulation in cancer, particularly aberrant ubiquitination, has drawn increasing interest in recent years. The present study aimed to review the roles of ubiquitin‑conjugating enzyme E2 T (UBE2T) and its associated pathways in the pathogenesis of pan‑cancer, and the development of small‑molecule modulators to regulate ubiquitination for treatment strategies. The current study comprehensively investigated the expression landscape and functional significance of UBE2T, as well as its correlation with cancer cell sensitivity to chemotherapy/radiotherapy. Multiple levels of evidence suggested that aberrant UBE2T played important roles in pan‑cancer. Information was collected from 16 clinical trials on ubiquitin enzymes, and it was found that these molecules had an important role in the ubiquitin‑proteasome system. Further studies are necessary to explore their feasibility and effectiveness as diagnostic and prognostic biomarkers, or as up/down‑stream and therapeutic targets for cancer treatment.

Ubiquitin‑conjugating enzymes as potential biomarkers and therapeutic targets for digestive system cancers (Review)

Digestive system cancers are the leading cause of cancer‑related death worldwide due to their high morbidity and mortality rates. The current treatment methods include surgical treatment, chemotherapy, radiotherapy and endoscopic treatment, and the precisely targeted therapy of digestive system cancers requires to be further studied. The ubiquitin‑proteasome system is the main pathway for protein degradation in cells and the ubiquitin‑conjugating enzymes (E2s) have a decisive role in the specific selection of target proteins for degradation. The E2s have an important physiological role in digestive system cancers, which is related to the clinical tumor stage, differentiation degree and poor prognosis. Furthermore, they are involved in the physiological processes of digestive system tumor cell proliferation, migration, invasion, stemness, drug resistance and autophagy. In the present article, the progress and achievements of the E2s in gastric cancer, hepatocellular carcinoma, pancreatic cancer, colorectal cancer, intrahepatic cholangiocarcinoma, gallbladder cancer and esophageal squamous cell carcinoma were reviewed, which may provide early screening indicators and reliable therapeutic targets for digestive system cancers.

Identification of a Five Immune Term Signature for Prognosis and Therapy Options (Immunotherapy versus Targeted Therapy) for Patients with Hepatocellular Carcinoma

Background

Immune microenvironment implicated in liver cancer development. Nevertheless, previous studies have not fully investigated the immune microenvironment in liver cancer.

Methods

The open-access data used for analysis were obtained from The Cancer Genome Atlas (TCGA-LIHC) and the International Cancer Genome Consortium databases (ICGC-JP and ICGC-FR). R program was employed to analyze all the data statistically.

Results

First, the TCGA-LIHC, ICGC-FR, and ICGC-JP cohorts were selected for our analysis, which were merged into a combined cohort. Then, we quantified 53 immune terms in this combined cohort with large populations using the ssGSEA algorithm. Next, a prognostic approach was established based on five immune principles (CORE.SERUM.RESPONSE.UP, angiogenesis, CD8.T.cells, Th2.cells, and B.cells) was established, which showed great prognostic prediction efficiency. Clinical correlation analysis demonstrated that high-risk patients could reveal higher progressive clinical features. Next, to examine the inherent biological variations in high- and low-risk patients, pathway enrichment tests were conducted. DNA repair, E2F targets, G2M checkpoints, HEDGEHOG signaling, mTORC1 signaling, and MYC target were positively correlated with the risk score. Examination of genomic instability revealed that high-risk patients may exhibit a higher tumor mutation burden score. Meanwhile, the risk score showed a strong positive correlation with the tumor stemness index. In addition, the Tumor Immune Dysfunction and Exclusion outcome indicated that high-risk patients could be higher responsive to immunotherapy, whereas low-risk patients may be higher responsive to Erlotinib. Finally, six characteristic genes DEPDC1, DEPDC1B, NGFR, CALCRL, PRR11, and TRIP13 were identified for risk group prediction.

Conclusions

In summary, our study identified a signature as a useful tool to indicate prognosis and therapy options for liver cancer patients.

Prognostic Value of UBE2T and Its Correlation with Immune Infiltrates in Lung Adenocarcinoma

Non-small cell lung cancer has a subtype with a high morbidity and mortality rate called lung adenocarcinoma (LUAD). It is critical to locate reliable prognostic biomarkers for LUAD at this time. Ubiquitin-conjugating enzyme E2T (UBE2T) has been found in numerous malignancies; however, its expression level and potential functions in LUAD are not completely understood at this time. A differentially expressed gene (DEG) screening method was used to identify genes that were expressed differently in 516 samples from LUAD and 59 samples from TCGA datasets. Clinicopathological markers were correlated with UBE2T expression. Using the Kaplan–Meier plotter database, UBE2T was evaluated for its prognostic value in the context of LUAD. In order to examine the importance of independent prognostic factors, both univariable and multivariable Cox regression models were applied. TIMER and CIBERSORT were utilized in order to investigate the connection that exists between UBE2T expression and tumor-infiltrating immune cells. This study collected 578 DEGs in total, as follows: 171 genes were significantly increased, while 408 genes were significantly decreased. We identified 9 survival-related DEGs in LUAD, including ASF1B, CA9, CCNB2, CCNE1, RRM2, SAPCD2, TCN1, TPX2, and UBE2T. Our attention focused on UBE2T, which was highly expressed in LUAD. A correlation was also found between high UBE2T expression and gender, age, advanced clinical stage, and decreased overall survival. In addition, multivariate analysis demonstrated UBE2T expression to be a significant independent diagnostic factor for patients suffering from LUAD. UBE2T was positively correlated with resting T cell CD4+ memory, myeloid dendritic cell resting, mast cell activated, macrophage M2, and B cell plasma, whereas it was negatively correlated with resting T cell CD4+ memory, MDC resting, MDC activated, macrophage M2, and B cell plasma. Overall, high expression levels of UBE2T correlated with poor overall survival in patients with LUAD, and UBE2T was an independent predictor involved in immune infiltration of LUAD. These findings offer fresh perspectives that contribute to our comprehension of the evolution of LUAD.

UBE2T regulates epithelial–mesenchymal transition through the PI3K-AKT pathway and plays a carcinogenic role in ovarian cancer

Background

Ubiquitin-binding enzyme E2T (UBE2T), a member of the E2 family of the ubiquitin–proteasome pathway, is associated with tumorigenesis of varioustumours; however, its role and mechanism in ovarian cancer remain unclear.

Results

Our study revealed that UBE2T is highly expressed in ovarian cancer; this high expression was closely related to poor prognosis. Immunohistochemistry was used to validate the high expression of UBE2T in ovarian cancer. This is the first study to demonstrate that UBE2T expression is higher in ovarian cancer with BRCA mutation. Moreover, we demonstrated that UBE2T gene silencing significantly inhibited ovarian cancer cell proliferation and invasion. The epithelial–mesenchymal transition (EMT) of ovarian cancer cells and phosphatidylinositol 3 kinase/protein kinase B (PI3K-AKT) pathway were significantly inhibited. Adding the mechanistic target of rapamycin activator MHY1485 activated the PI3K-AKT pathway and significantly restored the proliferative and invasive ability of ovarian cancer cells. Furthermore, a tumorigenesis experiment in nude mice revealed that tumour growth on mice body surface and tumour tissue EMT were significantly inhibited after UBE2T gene silencing.

Conclusions

This study demonstrated that UBE2T regulates EMT via the PI3K-AKT pathway and plays a carcinogenic role in ovarian cancer. Moreover, UBE2T may interact with BRCA to affect ovarian cancer occurrence and development. Hence, UBE2T may be a valuable novel biomarker for the early diagnosis and prognosis and treatment of ovarian cancer. Further, UBE2T inhibition may be effective for treating ovarian cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13048-022-01034-9.

Circ_0000291 contributes to hepatocellular carcinoma tumorigenesis by binding to miR-1322 to up-regulate UBE2T

INTRODUCTION AND OBJECTIVES

Circular RNAs (circRNAs) are identified to show important regulatory functions in cancer biology. We attempted to analyze the role of circ_0000291 in hepatocellular carcinoma (HCC) progression and its related mechanism.

METHODS

The circular characteristic of circ_0000291 was tested using exonuclease RNase R. Cell proliferation was analyzed by 5-Ethynyl-2'-deoxyuridine (EdU) incorporation and colony formation assays. Cell apoptosis was measured by flow cytometry and a caspase 3 activity assay kit. Transwell assays were performed to analyze cell migration and invasion abilities. Sphere formation assay was conducted to analyze cell stemness. Dual-luciferase reporter and RNA-pull down assays were conducted to verify the interaction between microRNA-1322 (miR-1322) and circ_0000291 or ubiquitin conjugating enzyme E2 T (UBE2T).

RESULTS

Circ_0000291 was markedly up-regulated in HCC tissues and cell lines. HCC patients with high expression of circ_0000291 displayed a low survival rate. Circ_0000291 knockdown restrained the proliferation, migration, invasion, and stemness and induced the apoptosis of HCC cells. Circ_0000291 directly interacted with miR-1322 and negatively regulated miR-1322 expression. Circ_0000291 knockdown-mediated anti-tumor impacts in HCC cells were largely overturned by the interference of miR-1322. miR-1322 directly paired with the 3' untranslated region (3'UTR) of UBE2T, and UBE2T was negatively regulated by miR-1322. UBE2T overexpression largely reversed circ_0000291 silencing-induced effects in HCC cells. Circ_0000291 positively regulated UBE2T expression by absorbing miR-1322 in HCC cells. Circ_0000291 silencing notably reduced the tumorigenic potential in vivo.

CONCLUSION

Circ_0000291 facilitated HCC progression by targeting miR-1322/UBE2T axis, which provided novel potential biomarkers and targets for HCC patients.

Low adipocyte hepatocellular carcinoma is associated with aggressive cancer biology and with worse survival

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide, and non-alcoholic fatty liver disease is strongly associated with its development. To explore the role of adipocytes in HCC, we investigated intratumoral adipocytes, also known as cancer-associated adipocytes (CAA). Based on our prior breast cancer findings, we hypothesized that low intratumoral adipocytes would be associated with aggressive cancer biology, worse tumor microenvironment (TME), and clinical outcomes. The Cancer Genome Atlas (TCGA) was used and validated by the Gene Expression Omnibus (GEO) cohort. xCell algorithm was used to quantify intratumoral adipocytes and top 90% were defined as adipocyte high (AH) and bottom 10% as adipocyte low (AL). We found that AL-HCC was significantly associated with worse disease-free survival (DFS), disease-specific survival (DSS), and overall survival (OS). AL-HCC were higher-grade, had high MKI67 expression, enriched cell proliferation-related gene sets, and had increased altered fraction, aneuploidy, and homologous recombination defects. Also, anti-cancer immune cells, CD8, Th1, and M1 cells, as well as pro-cancer Th2 cells were increased in AL-HCC. Micro-RNAs miR-122 (associated with cholesterol metabolism) and miR-885 (associated with liver pathologies) were significantly increased in the AL TME. In conclusion, we found that AL-HCC has worse patient outcomes and is biologically more aggressive with enhanced cell proliferation. Our findings take initial steps to clarify the role of adipocytes in HCC.

Functions of three ubiquitin-conjugating enzyme 2 genes in hepatocellular carcinoma diagnosis and prognosis

BACKGROUND

Liver cancer ranks the third cause of cancer-related death worldwide. The most common type of liver cancer is hepatocellular carcinoma (HCC). The survival time for HCC patients is very limited by years due to the lack of efficient treatment, failure of early diagnosis, and poor prognosis. Ubiquitination plays an essential role in the biochemical processes of a variety of cellular functions.

AIM

To investigate three ubiquitination-associated genes in HCC.

METHODS

Herein, the expression levels of ubiquitin-conjugating enzymes 2 (UBE2) including UBE2C, UBE2T, and UBE2S in tumor samples of HCC patients and non-tumor controls at the Cancer Genome Atlas (TCGA) database, was comprehensively analyzed. The relationship of UBE2 gene expression level with cancer stage, prognostic outcome, and TP53 mutant status was studied.

RESULTS

Our results showed that UBE2C, UBE2T, and UBE2S genes were overexpressed in HCC samples compared to non-tumor tissues. Dependent on the cancer progression stage, three UBE2 genes showed higher expression in tumor tissues at all four stages compared to non-tumor control samples. Furthermore, a significantly higher expression of these genes was found in stage 2 and stage 3 cancers compared to stage 1 cancer. Additionally, overexpression of those genes was negatively associated with prognostic outcome and overall survival time. Patients with TP53 mutation showed a higher expression level of three UBE2 genes, indicating an association between UBE2 expression with p53 function.

CONCLUSION

In summary, this study shed light on the potential roles of UBE2C, UBE2T, UBE2S on diagnostic and prognostic biomarkers for HCC. Moreover, based on our findings, it is appealing to further explore the correlation of those genes with TP53 mutation in HCC and the related mechanisms.

ANLN and UBE2T are prognostic biomarkers associated with immune regulation in breast cancer: a bioinformatics analysis

OBJECTIVES

To screen and verify differential genes affecting the prognosis of breast cancer.

METHODS

Breast cancer gene expression datasets were downloaded from the GEO database, and original data were analyzed in R. The TIMER database was used to analyze the relationship between ANLN and UBE2T and immune cell infiltration.

RESULTS

Ten hub-key genes were identified, and survival analysis showed that UBE2T and ANLN were upregulated in breast cancer and their upregulation was associated with a poor prognosis. ANLN and UBE2T upregulation was associated with the prevalence of Th1 and Th2 cells, shifting the Th1/Th2 balance to Th2 in Basal and Luminal-B breast cancers, which indicates a poor prognosis (P < 0.05).

CONCLUSION

ANLN and UBE2T are potential biomarkers for predicting the prognosis of breast cancer.

MiR-182-5p inhibits the tumorigenesis of clear cell renal cell carcinoma by repressing UBE2T

Ubiquitin-conjugating enzyme E2T (UBE2T), a member of the E2 family, has been reported to be overexpressed in certain tumor types and to have an important role in the Fanconi anemia pathway. However, the role of UBE2T in clear cell renal cell carcinoma (ccRCC) has not been clarified. MicroRNAs (miRNAs) participate in tumorigenesis by binding to genes and proteins that regulate cell proliferation or cell apoptosis. The aim of this study was to determine the role of UBE2T and the relationship between miR-182-5p and UBE2T in ccRCC. In the present study, UBE2T expression levels in ccRCC tissues and cells were assessed using real-time quantitative PCR (RT-qPCR) and western blotting. UBE2T protein expression was assessed in a total of 93 ccRCC patients from Peking University First Hospital (PKU) via immunohistochemistry (IHC). The effects of UBE2T knockdown on ccRCC cells were assessed with MTS assays, wound healing assays, Transwell invasion assays and flow cytometry. The effects of in vivo treatment were evaluated through xenograft experiments. The relationship between miR-182-5p and UBE2T was verified with a dual-luciferase reporter gene assay. We found that UBE2T was highly expressed in ccRCC cells and tissues. High UBE2T expression was positively correlated with advanced pathological stage, histological grade, maximum tumor diameter and distant metastasis. Multivariate analysis revealed that UBE2T expression was an independent risk factor for overall survival (OS) and recurrence-free survival (RFS) in patients with ccRCC. Knockdown of UBE2T significantly suppressed RCC cell proliferation, migration and invasion. Flow cytometry analysis showed that UBE2T knockdown promoted RCC cell cycle arrest at G2/M phase and increased cell apoptosis. The xenograft model confirmed that suppression of UBE2T significantly delayed tumor formation and growth in vivo. In addition, miR-182-5p inhibited UBE2T protein expression by targeting UBE2T mRNA and then inhibited the proliferation, migration and invasion of ccRCC cell. Our research reveals that UBE2T likely plays a critical role in ccRCC progression and may be a potential therapeutic target for ccRCC.

UBE2T-mediated Akt ubiquitination and Akt/β-catenin activation promotes hepatocellular carcinoma development by increasing pyrimidine metabolism

The oncogene protein ubiquitin-conjugating enzyme E2T (UBE2T) is reported to be upregulated in hepatocellular carcinoma (HCC) and correlated with poor clinical outcomes of HCC patients. However, the underlying mechanism by which UBE2T exerts its oncogenic function in HCC remains largely unexplored. In this study, in vitro and in vivo experiments suggested that UBE2T promoted HCC development including proliferation and metastasis. GSEA analysis indicated that UBE2T was positively correlated with pyrimidine metabolism, and LC/MS-MS metabolomics profiling revealed that the key products of pyrimidine metabolism were significantly increased in UBE2T-overexpressing cells. UBE2T overexpression led to the upregulation of several key enzymes catalyzing de novo pyrimidine synthesis, including CAD, DHODH, and UMPS. Moreover, the utilization of leflunomide, a clinically approved DHODH inhibitor, blocked the effect of UBE2T in promoting HCC progression. Mechanistically, UBE2T increased Akt K63-mediated ubiquitination and Akt/β-catenin signaling pathway activation. The disruption of UBE2T-mediated ubiquitination on Akt, including E2-enzyme-deficient mutation (C86A) of UBE2T and ubiquitination-site-deficient mutation (K8/14 R) of Akt impaired UBE2T’s effect in upregulating CAD, DHODH, and UMPS. Importantly, we demonstrated that UBE2T was positively correlated with p-Akt, β-catenin, CAD, DHODH, and UMPS in HCC tumor tissues. In summary, our study indicates that UBE2T increases pyrimidine metabolism by promoting Akt K63-linked ubiquitination, thus contributing to HCC development. This work provides a novel insight into HCC development and a potential therapeutic strategy for HCC patients.

Comprehensive analysis of differentially expressed genes reveals the promotive effects of UBE2T on colorectal cancer cell proliferation

Colorectal cancer (CRC) is one of the most common malignancies worldwide. Via analysis using The Cancer Genome Atlas database, the present study identified 1,835 genes that were differentially expressed in CRC, including 811 upregulated and 1,024 downregulated genes. Enrichment analyses using the Database for Annotation, Visualization and Integrated Discovery tool revealed that these differentially expressed genes were associated with the regulation of CRC progression by modulating multiple pathways, such as ‘Cell Cycle, Mitotic’, ‘DNA Replication’, ‘Mitotic M-M/G1 phases’ and ‘ATM pathway’. To identify the key genes in CRC, protein-protein interaction (PPI) network analysis was performed and the hub modules in upregulated and downregulated PPI networks were identified. Ubiquitin-conjugating enzyme E2 T (UBE2T), a member of the E2 family, was identified to be a key regulator in CRC. To the best of our knowledge, the present study was the first to demonstrate that UBE2T expression was upregulated in CRC samples compared with normal tissues. Kaplan-Meier analysis revealed that higher expression levels of UBE2T were associated with worse prognosis compared with lower UBE2T expression levels in CRC. Additionally, the present study demonstrated that knockdown of UBE2T inhibited CRC cell proliferation. Flow cytometry assays revealed that UBE2T knockdown induced cell cycle arrest at G₁ phase and apoptosis in vitro. These results suggested that UBE2T may be a novel potential biomarker for CRC.

DUSP12 regulates the tumorigenesis and prognosis of hepatocellular carcinoma

Background

Dual specificity protein phosphatase (DUSP)12 is an atypical member of the protein tyrosine phosphatase family, which are overexpressed in multiple types of malignant tumors. This protein family protect cells from apoptosis and promotes the proliferation and motility of cells. However, the pathological role of DUSP12 in hepatocellular carcinoma (HCC) is incompletely understood.

Methods

We analyzed mRNA expression of DUSP12 between HCC and normal liver tissues using multiple online databases, and explored the status of DUSP12 mutants using the cBioPortal database. The correlation between DUSP12 expression and tumor-infiltrating immune cells was demonstrated using the Tumor Immune Estimation Resource database and the Tumor and Immune System Interaction Database. Loss of function assay was utilized to evaluate the role of DUSP12 in HCC progression.

Results

DUSP12 had higher expression along with mRNA amplification in HCC tissues compared with those in normal liver tissues, which suggested that higher DUSP12 expression predicted shorter overall survival. Analyses of functional enrichment of differentially expressed genes suggested that DUSP12 regulated HCC tumorigenesis, and that knockdown of DUSP12 expression by short hairpin (sh)RNA decreased the proliferation and migration of HCC cells. Besides, DUSP12 expression was positively associated with the infiltration of cluster of differentiation (CD)4+ T cells (especially CD4+ regulatory T cells), macrophages, neutrophils and dendritic cells. DUSP12 expression was positively associated with immune-checkpoint moieties, and was downregulated in a C3 immune-subgroup of HCC (which had the longest survival).

Conclusion

These data suggest that DUSP12 may have a critical role in the tumorigenesis, infiltration of immune cells, and prognosis of HCC.

Deubiquitinase USP39 and E3 ligase TRIM26 balance the level of ZEB1 ubiquitination and thereby determine the progression of hepatocellular carcinoma

Emerging evidence suggests that USP39 plays an important role in the development of hepatocellular carcinoma (HCC). However, the molecular mechanism by which USP39 promotes HCC progression has not been well defined, especially regarding its putative ubiquitination function. Zinc-finger E-box-binding homeobox 1 (ZEB1) is a crucial inducer of epithelial-to-mesenchymal transition (EMT) to promote tumor proliferation and metastasis, but the regulatory mechanism of ZEB1 stability in HCC remains enigmatic. Here, we reveal that USP39 is highly expressed in human HCC tissues and correlated with poor prognosis. Moreover, USP39 depletion inhibits HCC cell proliferation and metastasis by promoting ZEB1 degradation. Intriguingly, deubiquitinase USP39 has a direct interaction with the E3 ligase TRIM26 identified by co-immunoprecipitation assays and immunofluorescence staining assays. We further demonstrate that TRIM26 is lowly expressed in human HCC tissues and inhibits HCC cell proliferation and migration. TRIM26 promotes the degradation of ZEB1 protein by ubiquitination in HCC. Deubiquitinase USP39 and E3 ligase TRIM26 function in an antagonistic pattern, but not a competitive pattern, and play key roles in controlling ZEB1 stability to determine the HCC progression. In summary, our data reveal a previously unknown mechanism that USP39 and TRIM26 balance the level of ZEB1 ubiquitination and thereby determine HCC cell proliferation and migration. This novel mechanism may provide new approaches to target treatment for inhibiting HCC development by restoring TRIM26 or suppressing USP39 expression in HCC cases with high ZEB1 protein levels.

Ubiquitin-conjugating enzyme E2T regulates cell proliferation and migration in cholangiocarcinoma

Ubiquitin-conjugating enzyme E2T (UBE2T) is overexpressed in several human cancer cells, but a role in cholangiocarcinoma (CAA) progression has not been investigated. We analyzed the expression of UBE2T in CAA tissues. Then, we generated UBE2T deregulation models in which it was overexpressed or silenced, and examined the effects on CAA malignant progression by flow cytometry, western blot, MTT assay, wound healing assay and transwell assay. We report the involvement of UBE2T in CAA malignant progression. UBE2T was found to be highly expressed in human CAA cells both in vitro and in vivo. Overexpression of UBE2T significantly enhanced epithelial-to-mesenchymal transition, proliferation, migration and invasion of CAA cells in vitro, while silencing UBE2T had opposing effects. Furthermore, UBE2T appears to exert its effects via the mammalian target of rapamycin (mTOR) pathway as the cellular effects caused by UBE2T overexpression are inhibited by the mTOR inhibitor rapamycin. Our findings suggest that UBE2T may have potential as a new therapeutic target for the prevention or treatment of CAA.

The Molecular Basis of Ubiquitin-Conjugating Enzymes (E2s) as a Potential Target for Cancer Therapy

Ubiquitin-conjugating enzymes (E2s) are one of the three enzymes required by the ubiquitin-proteasome pathway to connect activated ubiquitin to target proteins via ubiquitin ligases. E2s determine the connection type of the ubiquitin chains, and different types of ubiquitin chains regulate the stability and activity of substrate proteins. Thus, E2s participate in the regulation of a variety of biological processes. In recent years, the importance of E2s in human health and diseases has been particularly emphasized. Studies have shown that E2s are dysregulated in variety of cancers, thus it might be a potential therapeutic target. However, the molecular basis of E2s as a therapeutic target has not been described systematically. We reviewed this issue from the perspective of the special position and role of E2s in the ubiquitin-proteasome pathway, the structure of E2s and biological processes they are involved in. In addition, the inhibitors and microRNAs targeting E2s are also summarized. This article not only provides a direction for the development of effective drugs but also lays a foundation for further study on this enzyme in the future.

Identification of Biomarkers Based on Bioinformatics Analysis: The Expression of Ubiquitin-Conjugating Enzyme E2T (UBE2T) in the Carcinogenesis and Progression of Hepatocellular Carcinoma

BACKGROUND The purpose of this study was to screen and identify key genes in the occurrence and development of hepatocellular carcinoma (HCC) based on bioinformatics analysis. MATERIAL AND METHODS Three Gene Expression Omnibus (GEO) series (GSE) - GSE121248, GSE87630, and GSE84598 - were downloaded from the GEO database. GEO2R was used to screen different genes and a Venn diagram was drawn to screen coexpressed differentially expressed genes (DEGs). Coexpressed DEGs were obtained by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, a protein-protein interaction network diagram was produced by Cytoscape, and module genes were calculated by the Molecular Complex Detection Cytoscape plug-in. Finally, overall survival, progression-free survival, and relapse-free survival analysis of the key genes selected were performed using the online Kaplan-Meier plotter. For the target genes, the online network UCSC Cancer Genome Browser was used to analyze the gene expression profiles of the grade and vascular invasion of HCC. RESULTS A total of 296 coexpressed DEGs were obtained from the 3 GSEs and 12 key genes were obtained from the modular analysis. Survival analysis showed that the upregulated genes UBE2T and FBLN5 were involved in the poor prognosis of HCC. Furthermore, the expression of UBE2T was significantly related to the grade and vascular invasion of HCC. CONCLUSIONS The expression of the UBE2T gene was significantly upregulated in HCC tissue compared to in normal liver tissue. UBE2T may be a new marker for the diagnosis and subsequent therapy of HCC.

The interplay of UBE2T and Mule in regulating Wnt/β-catenin activation to promote hepatocellular carcinoma progression

Emerging evidence indicates the role of cancer stem cells (CSCs) in tumor relapse and therapeutic resistance in patients with hepatocellular carcinoma (HCC). To identify novel targets against liver CSCs, an integrative analysis of publicly available datasets involving HCC clinical and stemness-related data was employed to select genes that play crucial roles in HCC via regulation of liver CSCs. We revealed an enrichment of an interstrand cross-link repair pathway, in which ubiquitin-conjugating enzyme E2 T (UBE2T) was the most significantly upregulated. Consistently, our data showed that UBE2T was upregulated in enriched liver CSC populations. Clinically, UBE2T overexpression in HCC was further confirmed at mRNA and protein levels and was correlated with advanced tumor stage and poor patient survival. UBE2T was found to be critically involved in the regulation of liver CSCs, as evidenced by increases in self-renewal, drug resistance, tumorigenicity, and metastasis abilities. Mule, an E3 ubiquitin ligase, was identified to be the direct protein binding partner of UBE2T. Rather than the canonical role of acting as a mediator to transfer ubiquitin to E3 ligases, UBE2T is surprisingly able to physically bind and regulate the protein expression of Mule via ubiquitination. Mule was found to directly degrade β-catenin protein, and UBE2T was found to mediate liver CSC functions through direct regulation of Mule-mediated β-catenin degradation; this effect was abolished when the E2 activity of UBE2T was impaired. In conclusion, we revealed a novel UBE2T/Mule/β-catenin signaling cascade that is involved in the regulation of liver CSCs, which provides an attractive potential therapeutic target for HCC.

A novel UBE2T inhibitor suppresses Wnt/β-catenin signaling hyperactivation and gastric cancer progression by blocking RACK1 ubiquitination

Dysregulation of the Wnt/β-catenin signaling pathway is critically involved in gastric cancer (GC) progression. However, current Wnt pathway inhibitors being studied in preclinical or clinical settings for other cancers such as colorectal and pancreatic cancers are either too cytotoxic or insufficiently efficacious for GC. Thus, we screened new potent targets from β-catenin destruction complex associated with GC progression from clinical samples, and found that scaffolding protein RACK1 deficiency plays a significant role in GC progression, but not APC, AXIN, and GSK3β. Then, we identified its upstream regulator UBE2T which promotes GC progression via hyperactivating the Wnt/β-catenin signaling pathway through the ubiquitination and degradation of RACK1 at the lysine K172, K225, and K257 residues independent of an E3 ligase. Indeed, UBE2T protein level is negatively associated with prognosis in GC patients, suggesting that UBE2T is a promising target for GC therapy. Furthermore, we identified a novel UBE2T inhibitor, M435-1279, and suggested that M435-1279 acts inhibit the Wnt/β-catenin signaling pathway hyperactivation through blocking UBE2T-mediated degradation of RACK1, resulting in suppression of GC progression with lower cytotoxicity in the meantime. Overall, we found that increased UBE2T levels promote GC progression via the ubiquitination of RACK1 and identified a novel potent inhibitor providing a balance between growth inhibition and cytotoxicity as well, which offer a new opportunity for the specific GC patients with aberrant Wnt/β-catenin signaling.

Increased Expression of UBE2T Predicting Poor Survival of Epithelial Ovarian Cancer: Based on Comprehensive Analysis of UBE2s, Clinical Samples, and the GEO Database

Ubiquitin-conjugating enzymes E2 (UBE2) have been reported in the microenvironment of various malignant tumors, but their correlation with ovarian cancer (OC) remains elusive. This study aimed to systematically analyze the expression patterns, prognostic value, genetic variation, and biological functions of 12 members of the UBE2 gene family in OC through the Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier plotter, cBioPortal, and Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) databases, respectively. We found that the mRNA levels of UBE2C, UBE2N, UBE2S, and UBE2T were significantly upregulated in OC compared with those in normal ovarian tissue. In patients with serous ovarian cancer (SOC), UBE2A, UBE2B, UBE2C, UBE2G, UBE2R2, and UBE2T upregulation were associated with poor overall survival. Moreover, UBE2A, UBE2N, UBE2R2, and UBE2T upregulation and UBE2G downregulation were associated with poor progression-free survival. UBE2T exhibited a strong correlation with OC and was thus further examined. We found that UBE2T has a high diagnostic accuracy (area under the receiver operating characteristic curve = 0.969) in epithelial ovarian cancer (EOC). Immunohistochemical assays and the Gene Expression Omnibus (GEO) database revealed that UBE2T was significantly upregulated in EOC compared with that in borderline tumors, benign tumors, and normal ovarian tissues, and its high expression was associated with poor prognosis. The Cox model showed that UBE2T upregulation was an independent risk factor affecting the prognosis of EOC and SOC. Furthermore, UBE2T was associated with specific immune cells and was mainly involved in cell cycle-related events. Genomic analysis showed that TP53 and TTN mutations were associated with UBE2T expression. Gene copy number amplification and hypomethylation may be responsible for UBE2T upregulation in OC. In conclusion, UBE2 family members may play a role in the development of OC. Specifically, UBE2T could serve as a new prognostic marker and therapeutic target for this disease. (IRB Approval No. 2020PS533K).

RNF128 Promotes Malignant Behaviors via EGFR/MEK/ERK Pathway in Hepatocellular Carcinoma

Background

The ubiquitin-proteasome system participates in the pathogenesis and progression of hepatocellular carcinoma (HCC). As an E3 ubiquitin ligase, RNF128 has been proved vital in carcinogenesis, whereas, little is known about the oncogenic mechanisms of RNF128 in HCC.

Materials and Methods

Through tissue microarray from HCC patients, we analyzed RNF128 expression and its relationship with clinical outcomes in HCC. Western blot and quantitative realtime polymerase chain reaction (qRT-PCR) were performed to examine expression levels of RNF128 in HCC tissues and cell lines. Effects of RNF128 on HCC cellular biological functions and the potential mechanism were evaluated through knockdown and overexpression assays in vitro and in vivo methods.

Results

RNF128 expression was found to be remarkably elevated in HCC tissues compared with adjacent normal tissues. Furthermore, the overexpression of RNF128 enhanced hepatoma cells proliferation, colony formation, migration, invasion, and apoptotic resistance both in vitro and in vivo. Mechanistically, RNF128 activated EGFR/MEK/ERK signaling pathway and the EGFR inhibitor, gefitinib partially reversed RNF128-enhanced proliferation, invasion, and migration in hepatoma cells.

Conclusion

RNF128 promotes HCC progression by activating EGFR/MEK/ERK signaling pathway, which might function as a novel prognostic molecular signature with the potential to be a candidate therapeutic target for HCC patients.

UBE2T promotes glioblastoma invasion and migration via stabilizing GRP78 and regulating EMT

Glioblastoma (GBM) generally has a dismal prognosis, and it is associated with a poor quality of life as the disease progresses. However, the development of effective therapies for GBM has been deficient. Ubiquitin-conjugating enzyme E2T (UBE2T) is a member of the E2 family in the ubiquitin-proteasome pathway and a vital regulator of tumour progression, but its role in GBM is unclear. In this study, we aimed to clarify the role of UBE2T in GBM. Bioinformatics analysis identified UBE2T as an independent risk factor for gliomas. Immunohistochemistry was used to measure UBE2T expression in GBM and normal tissue samples obtained from patients with GBM. The effects of UBE2T on GBM cell invasion and migration were analysed using the Transwell assay. BALB/c nude mice were used for the in vivo assays. Immunoblotting and immunoprecipitation were performed to determine the molecular mechanisms. UBE2T was highly expressed in GBM tissues, and its expression was linked to a poor prognosis. In vitro, depletion of UBE2T significantly suppressed cell invasion and migration. Moreover, UBE2T depletion suppressed the growth of GBM subcutaneous tumours in vivo. Further experiments revealed that UBE2T suppressed invasion and migration by regulating epithelial- mesenchymal transition (EMT) via stabilising GRP78 in GBM cells. We uncovered a novel UBE2T/GRP78/EMT regulatory axis that modulates the malignant progression and recurrence of GBM, indicating that the axis might be a valuable therapeutic target.

Screening of the Hepatotoxic Components in Fructus Gardeniae and Their Effects on Rat Liver BRL-3A Cells

Fructus Gardeniae (FG) is a common Chinese medicine and food. However, the toxicity of FG has drawn increasing concern, especially its hepatotoxicity. The purpose of this study was to screen the hepatotoxic components of FG and evaluate their effects on rat liver BRL-3A cells. The chemical composition of FG was determined by HPLC-ESI-MS. CCK-8 assay was used to evaluate the cytotoxicity of ten chemical components from FG, and then the toxic components with significant inhibitory activity were selected for further study. The results showed that geniposide, genipin, genipin-1-gentiobioside, gardenoside, and shanzhiside all suppress cells viability. Apoptosis assays further indicated that geniposide and its metabolite genipin are the main hepatotoxic components of FG. Pretreatment of cells with geniposide or genipin increased the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). The activities of superoxide dismutase (SOD) and glutathione (GSH) were decreased, while the malondialdehyde (MDA) level was increased. The cell contents of tumor necrosis factor (TNF-α), interleukin-6 (IL-6), and nitric oxide (NO) were also increased. Molecular docking simulations were used to investigate the mechanism of FG-induced hepatotoxicity, revealing that geniposide and genipin bind strongly to the pro-inflammatory factor TNFR1 receptor of the NF-κB and MAPK signaling pathways. The obtained results strongly indicate that the hepatotoxicity of FG is caused by iridoids compounds. Genipin had the most significant hepatotoxic effect. These toxic substances destroy the cell antioxidant defense system, increasing inflammatory injury to the liver cells and leading to apoptosis and even necrosis. Thus, this study lays a foundation for toxicology research into FG and its rational application.