Ube2S regulates Wnt/β-catenin signaling and promotes the progression of non-small cell lung cancer

Diverse roles of UBE2S in cancer and therapy resistance: Biological functions and mechanisms

The Ubiquitin Conjugating Enzyme E2 S (UBE2S), was initially identified as a crucial member in controlling substrate ubiquitination during the late promotion of the complex's function. In recent years, UBE2S has emerged as a significant epigenetic modification in various diseases, including myocardial ischemia, viral hepatitis, and notably, cancer. Mounting evidence suggests that UBE2S plays a pivotal role in several human malignancies including breast cancer, lung cancer, hepatocellular carcinoma and etc. However, a comprehensive review of UBE2S in human tumor research remains absent. Therefore, this paper aims to fill this gap. This review provides a comprehensive analysis of the structural characteristics of UBE2S and its potential utility as a biomarker in diverse cancer types. Additionally, the role of UBE2S in conferring resistance to tumor treatment is examined. The findings suggest that UBE2S holds promise as a diagnostic and therapeutic target in multiple malignancies, thereby offering novel avenues for cancer therapy.

Activation of PI3K/AKT/mTOR signaling axis by UBE2S inhibits autophagy leading to cisplatin resistance in ovarian cancer

BACKGROUND

Epithelial ovarian cancer (OC) is the fourth leading cause of cancer-related deaths in women, with a 5-year survival rate of 30%-50%. Platinum resistance is the chief culprit for the high recurrence and mortality rates. Several studies confirm that the metabolic regulation of ubiquitinating enzymes plays a vital role in platinum resistance in OC.

METHODS

In this study, we selected ubiquitin-conjugating enzyme E2S (UBE2S) as the candidate gene for validation. The levels of UBE2S expression were investigated using TCGA, GTEx, UALCAN, and HPA databases. In addition, the correlation between UBE2S and platinum resistance in OC was analyzed using data from TCGA. Cisplatin-resistant OC cell lines were generated and UBE2S was knocked down; the transfection efficiency was verified. Subsequently, the effects of knockdown of UBE2S on the proliferation and migration of cisplatin-resistant OC cells were examined through the CCK8, Ki-67 immunofluorescence, clone formation, wound healing, and transwell assays. In addition, the UBE2S gene was also validated in vivo by xenograft models in nude mice. Finally, the relationship between the UBE2S gene and autophagy and the possible underlying regulatory mechanism was preliminarily investigated through MDC and GFP-LC3-B autophagy detection and western blotting experiments. Most importantly, experimental validation of mTOR agonist reversion (the rescuse experiments) was also performed.

RESULTS

UBE2S was highly expressed in OC at both nucleic acid and protein levels. The results of immunohistochemistry showed that the level of UBE2S expression in platinum-resistant samples was significantly higher relative to the platinum-sensitive samples. By cell transfection experiments, knocking down of the UBE2S gene was found to inhibit the proliferation and migration of cisplatin-resistant OC cells. Moreover, the UBE2S gene could inhibit autophagy by activating the PI3K/AKT/mTOR signaling pathway to induce cisplatin resistance in OC in vivo and in vitro.

CONCLUSION

In conclusion, we discovered a novel oncogene, UBE2S, which was associated with platinum response in OC, and examined its key role through bioinformatics and preliminary experiments. The findings may open up a new avenue for the evaluation and treatment of OC patients at high risk of cisplatin resistance.

A prognostic model of drug tolerant persister-related genes in lung adenocarcinoma based on single cell and bulk RNA sequencing data

Background

Acquired resistance to targeted drugs is a major challenge in cancer. The drug-tolerant state has been proposed to be an initial step towards acquisition of real drug-resistance. Drug tolerant persister (DTP) cells are purported to survive during treatment and stay dormant for several years. Single cell sequencing can provide a comprehensive landscape of gene expression in DTP cells, which can facilitate investigation of heterogeneity of a drug tolerant state and identification of new anticancer targets.

Methods

The genetic profiling of DTPs was explored by integrating Gene Expression Omnibus (GEO) datasets, and a prognostic signature of DTP-related genes (DTPRGs) in lung adenocarcinoma of TCGA LUAD cohort was constructed. The scores of infiltrating immune cells were calculated and activity of immune-related pathways was evaluated by single-sample gene set enrichment analysis (ssGSEA). Functional enrichment analysis of the DTPRGs between low- and high-risk groups was performed. Immune cell subtypes and immune-related pathways were analyzed.

Results

An 11-gene panel (MT2A, UBE2S, CLTB, KRT7, IGFBP3, CTSH, NPC2, HMGA1, HNRNPAB, DTYMK, and IHNA) was established. DTPRGs were mainly correlated with nuclear division, chromosome segregation, and cell cycle pathways. Infiltration of immune cells was lower in the high-risk group while the inflammation-promoting and MCH-class I response pathway had higher activity in the high-risk group. A nomogram was generated with prognostic accuracy, further validated using clinical outcomes following therapy with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs).

Discussion

A prognostic model of lung adenocarcinoma based on DTPRGs was constructed. Targeting DTP cells is a potential therapeutic approach to prevent a drug tolerant state.

UBE2C serves as a prognosis biomarker of uterine corpus endometrial carcinoma via promoting tumor migration and invasion

The biological functions of ubiquitin-conjugating enzymes E2 (UBE2) family members in uterine corpus endometrial carcinoma (UCEC) remains unclear. Our study aimed to systematically analyze the expression patterns, prognostic value, biological functions and molecular regulatory mechanisms of UBE2 family in UCEC. Among nine screened UBE2 family members associated with UCEC, UBE2C was the most significantly overexpressed gene with poor prognosis. High expression levels of UBE2C in UCEC was correlated with stages, histological subtypes, patient's menopause status and TP53 mutation. Three molecules (CDC20, PTTG1 and AURKA), were identified as the key co-expression proteins of UBE2C. The generic alterations (mutation, amplification) and DNA hypomethylation might contribute to UBE2C's high expression in UCEC. Furthermore, in vitro experiments showed that the interference of UBE2C inhibited the migration and invasion of endometrial cancer cells, while partially impact cell proliferation and didn't impact the expression of epithelial-mesenchymal transition (EMT) markers. Using comprehensive bioinformatics analysis and in vitro experiments, our study provided a novel insight into the oncogenic role of UBE2 family, specifically UBE2C in UCEC. UBE2C might serve as an effective biomarker to predict poor prognosis and a potential therapeutic target in clinical practice.

As a potential predictor of pan-cancer, UBE2S is related to tumor-associated macrophage infiltration

Background: At the pan-cancer level, exploring the expression and prognostic significance of a gene, such as UBE2S, will help to gain insight into the role of the gene and its feasibility for cancer screening, prognosis assessment and even gene therapy. Methods: The Cancer Genome Atlas, Human Protein Atlas, Kaplan-Meier, Tumor Immunology Estimation Resource and other databases were used to analyze the expression of UBE2S at the pan-cancer level, its prognosis and the role of the immune microenvironment. Immunohistochemistry samples of tumor tissue collected in our clinic were taken as verification. Results: UBE2S is significantly overexpressed in pan-cancer and is closely associated with malignant clinical features, poor prognosis and tumor-associated macrophages. Conclusion: UBE2S may be a potential diagnostic and prognostic marker for pan-cancer and is associated with tumor-associated macrophages.

UBE2S targets RPL26 for ubiquitination and degradation to promote non-small cell lung cancer progression via regulating c-Myc

Multiple studies have shown that E2 conjugating enzyme family are dysregulated in various cancers and associated with tumor progression and poor prognosis. In present study, we screened and confirmed that UBE2S is one of the E2 conjugating enzymes highly expressed in non-small cell lung cancer (NSCLC), and it plays an oncogenic role by enhancing cell proliferation, migration and stemness in vitro. Using immunoprecipitation technology combined with mass spectrometry assay, we identified ribosomal protein RPL26 as the substrate protein of UBE2S in NSCLC. At the molecular level, overexpression of UBE2S accelerated the ubiquitination and degradation of RPL26, thus upregulating c-Myc to enhance the progression of NSCLC. In addition, the results of a xenograft experiment showed that inhibiting UBE2S could suppress RPL26-c-Myc mediated NSCLC tumor growth in vivo. Our data provided mechanistic evidence supporting the existence of a novel UBE2S-RPL26-c-Myc axis and its critical contribution to progression of NSCLC.

Development and validation of a tumor immune cell infiltration-related gene signature for recurrence prediction by weighted gene co-expression network analysis in prostate cancer

Introduction: Prostate cancer (PCa) is the second most common malignancy in men. Despite multidisciplinary treatments, patients with PCa continue to experience poor prognoses and high rates of tumor recurrence. Recent studies have shown that tumor-infiltrating immune cells (TIICs) are associated with PCa tumorigenesis.

Methods: The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets were used to derive multi-omics data for prostate adenocarcinoma (PRAD) samples. The CIBERSORT algorithm was used to calculate the landscape of TIICs. Weighted gene co-expression network analysis (WGCNA) was performed to determine the candidate module most significantly associated with TIICs. LASSO Cox regression was applied to screen a minimal set of genes and construct a TIIC-related prognostic gene signature for PCa. Then, 78 PCa samples with CIBERSORT output p-values of less than 0.05 were selected for analysis. WGCNA identified 13 modules, and the MEblue module with the most significant enrichment result was selected. A total of 1143 candidate genes were cross-examined between the MEblue module and active dendritic cell-related genes.

Results: According to LASSO Cox regression analysis, a risk model was constructed with six genes (STX4, UBE2S, EMC6, EMD, NUCB1 and GCAT), which exhibited strong correlations with clinicopathological variables, tumor microenvironment context, antitumor therapies, and tumor mutation burden (TMB) in TCGA-PRAD. Further validation showed that the UBE2S had the highest expression level among the six genes in five different PCa cell lines.

Discussion: In conclusion, our risk-score model contributes to better predicting PCa patient prognosis and understanding the underlying mechanisms of immune responses and antitumor therapies in PCa.

UBE2S and UBE2C confer a poor prognosis to breast cancer via downregulation of Numb

Purpose

Ubiquitin-conjugating enzymes E2S (UBE2S) and E2C (UBE2C), which mediate the biological process of ubiquitination, have been widely reported in various cancers. Numb, the cell fate determinant and tumor suppressor, was also involved in ubiquitination and proteasomal degradation. However, the interaction between UBE2S/UBE2C and Numb and their roles in the clinical outcome of breast cancer (BC) are not widely elucidated.

Methods

Oncomine, Cancer Cell Line Encyclopedia (CCLE), the Human Protein Atlas (HPA) database, qRT-PCR, and Western blot analyses were utilized to analyze UBE2S/UBE2C and Numb expression in various cancer types and their respective normal controls, breast cancer tissues, and breast cancer cell lines. The expression of UBE2S, UBE2C, and Numb in BC patients with different ER, PR, and HER2 status, grades, stages, and survival status was compared. By Kaplan-Meier plotter, we further evaluated the prognostic value of UBE2S, UBE2C, and Numb in BC patients. We also explored the potential regulatory mechanisms underlying UBE2S/UBE2C and Numb through overexpression and knockdown experiments in BC cell lines and performed growth and colony formation assays to assess cell malignancy.

Results

In this study, we showed that UBE2S and UBE2C were overexpressed while Numb was downregulated in BC, and in BC of higher grade, stage, and poor survival. Compared to hormone receptor negative (HR-) BC cell lines or tissues, HR+ BC demonstrated lower UBE2S/UBE2C and higher Numb, corresponding to better survival. We also showed that increased UBE2S/UBE2C and reduced Numb predicted poor prognosis in BC patients, as well as in ER+ BC patients. In BC cell lines, UBE2S/UBE2C overexpression decreased the level of Numb and enhanced cell malignancy, while knocking down UBE2S/UBE2C demonstrated the opposite effects.

Conclusion

UBE2S and UBE2C downregulated Numb and enhanced BC malignancy. The combination of UBE2S/UBE2C and Numb could potentially serve as novel biomarkers for BC.

Gene signature and prognostic value of ubiquitination-related genes in endometrial cancer

Protein ubiquitination is closely related to tumor occurrence and development. The specific role of ubiquitination in endometrial cancer remains largely unclear. Therefore, we constructed a novel endometrial cancer prognostic model based on ubiquitination-related genes. We extracted the expression matrices of ubiquitination-related genes from the Cancer Genome Atlas database, upon which we performed univariate Cox regression and least absolute shrinkage and selection operator (LASSO) regression analyses to obtain 22 ubiquitination-related genes for the construction of the prognostic model. Survival, regression, clinical correlation, and principal component analyses were performed to assess the performance of the model. Drug sensitivity analysis was performed based on these ubiquitination-related genes. Finally, a prognostic nomogram was constructed based on the prognostic model to quantify patient outcomes. Survival, regression, clinical correlation, and principal component analyses revealed that the performance of the prognostic model was satisfactory. Drug sensitivity analysis provided a potential direction for the treatment of endometrial cancer. The prognostic nomogram could be used to effectively estimate the survival rate of patients with endometrial cancer. In summary, we constructed a new endometrial cancer prognostic model and identified 5 differentially expressed, prognosis-associated, ubiquitination-related genes. These 5 genes are potential diagnostic and treatment targets for endometrial cancer.

Expression patterns of platinum resistance-related genes in lung adenocarcinoma and related clinical value models

The purpose of this study was to explore platinum resistance-related biomarkers and mechanisms in lung adenocarcinoma. Through the analysis of gene expression data of lung adenocarcinoma patients and normal patients from The Cancer Genome Atlas, Gene Expression Omnibus database, and A database of genes related to platinum resistance, platinum resistance genes in lung adenocarcinoma and platinum resistance-related differentially expressed genes were obtained. After screening by a statistical significance threshold, a total of 252 genes were defined as platinum resistance genes with significant differential expression, of which 161 were up-regulated and 91 were down-regulated. The enrichment results of up-regulated gene Gene Ontology (GO) showed that TOP3 entries related to biological processes (BP) were double-strand break repair, DNA recombination, DNA replication, the down-regulated gene GO enriches the TOP3 items about biological processes (BP) as a response to lipopolysaccharide, muscle cell proliferation, response to molecule of bacterial origin. Gene Set Enrichment Analysis showed that the top three were e2f targets, g2m checkpoint, and rgf beta signaling. A prognostic model based on non-negative matrix factorization classification showed the characteristics of high- and low-risk groups. The prognostic model established by least absolute shrinkage and selection operator regression and risk factor analysis showed that genes such as HOXB7, NT5E, and KRT18 were positively correlated with risk score. By analyzing the differences in m6A regulatory factors between high- and low-risk groups, it was found that FTO, GPM6A, METTL3, and YTHDC2 were higher in the low-risk group, while HNRNPA2B1, HNRNPC, TGF2BP1, IGF2BP2, IGF2BP3, and RBM15B were higher in the high-risk group. Immune infiltration and drug sensitivity analysis also showed the gene characteristics of the platinum-resistant population in lung adenocarcinoma. ceRNA analysis showed that has-miR-374a-5p and RP6-24A23.7 were lower in the tumor expression group, and that the survival of the low expression group was worse than that of the high expression group. In conclusion, the results of this study show that platinum resistance-related differentially expressed genes in lung adenocarcinoma are mainly concentrated in biological processes such as DNA recombination and response to lipopolysaccharide. The validation set proved that the high-risk group of our prognostic model had poor survival. M6A regulatory factor analysis, immune infiltration, and drug sensitivity analysis all showed differences between high and low-risk groups. ceRNA analysis showed that has-miR-374a-5p and RP6-24A23.7 could be protective factors. Further exploration of the potential impact of these genes on the risk and prognosis of drug-resistant patients with lung adenocarcinoma would provide theoretical support for future research.

Identification of the hub and prognostic genes in liver hepatocellular carcinoma via bioinformatics analysis

Hepatocellular carcinoma (HCC) is a common malignancy. However, the molecular mechanisms of the progression and prognosis of HCC remain unclear. In the current study, we merged three Gene Expression Omnibus (GEO) datasets and combined them with The Cancer Genome Atlas (TCGA) dataset to screen differentially expressed genes. Furthermore, protein‒protein interaction (PPI) and weighted gene coexpression network analysis (WGCNA) were used to identify key gene modules in the progression of HCC. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses indicated that the terms were associated with the cell cycle and DNA replication. Then, four hub genes were identified (AURKA, CCNB1, DLGAP5, and NCAPG) and validated via the expression of proteins and transcripts using online databases. In addition, we established a prognostic model using univariate Cox proportional hazards regression and least absolute shrinkage and selection operator (LASSO) regression. Eight genes were identified as prognostic genes, and four genes (FLVCR1, HMMR, NEB, and UBE2S) were detrimental gens. The areas under the curves (AUCs) at 1, 3 and 5 years were 0.622, 0.69, and 0.684 in the test dataset, respectively. The effective of prognostic model was also validated using International Cancer Genome Consortium (ICGC) dataset. Moreover, we performed multivariate independent prognostic analysis using multivariate Cox proportional hazards regression. The results showed that the risk score was an independent risk factor. Finally, we found that all prognostic genes had a strong positive correlation with immune infiltration. In conclusion, this study identified the key hub genes in the development and progression of HCC and prognostic genes in the prognosis of HCC, which was significant for the future diagnosis and prognosis of HCC.

Knockout of UBE2S inhibits the proliferation of gastric cancer cells and induces apoptosis by FAS-mediated death receptor pathway

Ubiquitin binding enzyme E2S (UBE2S) is a member of ubiquitin binding enzyme family involved in a variety of biological functions, including cell cycle regulation, apoptosis, and regulation of the ubiquitination of proteins, which are closely correlated with the development of various tumors. However, its role in gastric cancer (GC) remains unknown. In this study, we found that UBE2S was upregulated in GC tissues and cells. Further, its high expression positively correlated with the tumor stage and indicated a poor prognosis. Knockout of UBE2S by CRISPR/Cas9-mediated strategy suppressed the growth of GC in vitro and in vivo. Moreover, RNA-Seq-based transcriptome analysis and tandem mass tag (TMT)-based quantitative proteomics analysis was performed for exploring the underlying mechanism. The multi-omics and verification results showed that UBE2S knockout-induced apoptosis and proliferation inhibition of GC cells was related to upregulation of FAS and the activation of the FAS-mediated apoptotic pathway. Moreover, a negative correlation between UBE2S and FAS expression was observed in GC tissue samples. Finally, the ubiquitination assay confirmed that knockout of UBE2S might activate endogenous FAS by inhibiting ubiquitination and degradation of p53 in GC cells. Collectively, UBE2S is expected to be a novel prognostic biomarker and potential therapeutic target for GC.

UBE2S promotes the development of ovarian cancer by promoting PI3K/AKT/mTOR signaling pathway to regulate cell cycle and apoptosis

Background

Ovarian cancer is one of the important factors that seriously threaten women's health and its morbidity and mortality ranks eighth among female cancers in the world. It is critical to identify potential and promising biomarkers for prognostic evaluation and molecular therapy of OV. Ubiquitin-conjugating enzyme E2S (UBE2S), a potential oncogene, regulates the malignant progression of various tumors; however, its role in OV is still unclear.

Methods

The expression and prognostic significance of UBE2S at the pan-cancer level were investigated through high-throughput gene expression analysis and clinical prognostic data from TCGA, GEPIA, and GEO databases. 181 patients with OV were included in this study. Cell culture and cell transfection were performed on OV cell lines (SKOV3 and A2780) and a normal ovarian cell line (IOSE80). The expression level and prognostic significance of UBE2S in OV were verified by western blot, immunohistochemistry, and Kaplan–Meier survival analysis. Through cell transfection, CCK-8, Ki-67 immunofluorescence, wound healing, Transwell, clonogenic, and flow cytometry assays, the effect and detailed mechanism of UBE2S knockdown on the malignant biological behavior of OV cells were explored.

Results

UBE2S exhibited abnormally high expression at the pan-cancer level. The results of RT-qPCR and Western blotting indicated that UBE2S was significantly overexpressed in ovarian cancer cell lines compared with normal cell lines (P < 0.05). Kaplan–Meier survival analysis and Immunohistochemistry indicated that overexpression of UBE2S was related to poor prognosis of OV (HR > 1, P < 0.05). Results of in vitro experiments indicated that UBE2S gene knockdown might inhibit the proliferation, invasion, and prognosis of OV cells by inhibiting the PI3K/AKT/mTOR signaling pathway, thereby blocking the cell cycle and promoting apoptosis (P < 0.05).

Conclusion

UBE2S is a potential oncogene strongly associated with a poor prognosis of OV patients. Knockdown of UBE2S could block the cell cycle and promote apoptosis by inhibiting the PI3K/AKT/mTOR pathway and ultimately inhibit the proliferation, migration and prognosis of ovarian cancer, which suggested that UBE2S might be used for molecular therapy and prognostic evaluation of ovarian cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00489-2.

Hybrid gene selection approach using XGBoost and multi-objective genetic algorithm for cancer classification

Microarray gene expression data are often accompanied by a large number of genes and a small number of samples. However, only a few of these genes are relevant to cancer, resulting in significant gene selection challenges. Hence, we propose a two-stage gene selection approach by combining extreme gradient boosting (XGBoost) and a multi-objective optimization genetic algorithm (XGBoost-MOGA) for cancer classification in microarray datasets. In the first stage, the genes are ranked using an ensemble-based feature selection using XGBoost. This stage can effectively remove irrelevant genes and yield a group comprising the most relevant genes related to the class. In the second stage, XGBoost-MOGA searches for an optimal gene subset based on the most relevant genes' group using a multi-objective optimization genetic algorithm. We performed comprehensive experiments to compare XGBoost-MOGA with other state-of-the-art feature selection methods using two well-known learning classifiers on 14 publicly available microarray expression datasets. The experimental results show that XGBoost-MOGA yields significantly better results than previous state-of-the-art algorithms in terms of various evaluation criteria, such as accuracy, F-score, precision, and recall.

UBE2S exerts oncogenic activities in urinary bladder cancer by ubiquitinating TSC1

Ubiquitin-conjugating enzyme E2S (UBE2S), an important E2 enzyme in the process of ubiquitination, has exhibited oncogenic activities in various malignant tumors. However, it remains unknown whether UBE2S plays a role in urinary bladder cancer (UBC) development. In the current study, our data confirmed UBE2S upregulation in UBC. In vitro and in vivo experiments demonstrated that UBE2S knockdown resulted in attenuated proliferation and enhanced apoptosis, which was inverse to the phenotypes with UBE2S overexpression. Gain and loss of function assays confirmed that UBE2S exerts oncogenic activities in UBC by mediating the activation of the mammalian target of rapamycin complex 1 (mTORC1) pathway. Furthermore, we discovered that this UBE2S-modulated carcinogenic mechanism was in the consequence of directly targeting tuberous sclerosis 1 (TSC1), which is the upstream inhibitor of mTOR signaling for ubiquitous degradation. Taken together, this study demonstrated that UBE2S is a carcinogen in UBC and promotes UBC progression by ubiquitously degrading TSC1. This consequently mediates the activation of the mTOR pathway, suggesting a potential therapeutic regimen for UBC by targeting the newly identified UBE2S/TSC1/mTOR axis.

Identifying the hub genes in non-small cell lung cancer by integrated bioinformatics methods and analyzing the prognostic values

BACKGROUND

Lung cancer, a malignant tumor, has the highest mortality and second most common morbidity worldwide. Non-small cell lung cancer (NSCLC) is the most common pathological subtype of lung cancer. This study aimed to identify the gene signature associated with the NSCLC prognosis using bioinformatics analysis.

MATERIALS AND METHODS

The dataset GSE103512 was utilized to construct co-expression networks using weighted gene co-expression network analysis (WGCNA). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed using Database for Annotation, Visualization, and Integrated Discovery. Gene set enrichment analysis was conducted to ascertain the function of the hub genes more accurately. The relationship between the hub genes and immune infiltration was investigated using a single sample gene set enrichment analysis. Hub genes were screened and validated by other datasets and online websites.

RESULTS

The results of WGCNA demonstrated that the blue module was most significantly related to tumor progression in NSCLC. Functional enrichment analysis showed that the blue module was associated with DNA replication, cell division, mitotic nuclear division, and cell cycle. A total of five hub genes (RFC5, UBE2S, CHAF1A, FANCI, and TMEM194A) were chosen to be identified and validated at transcriptional and translational levels. Receiver operating characteristic curve verified that the mRNA levels of these five genes can excellently discriminate between normal and tumor tissues. Survival analysis was also performed. Additionally, the protein levels of these five genes were also significantly different between tumor and normal tissues. Immune infiltration analysis showed that the expression levels of the hub genes had a negative correlation with the infiltration levels of many cells related to innate immune response, antigen-presenting process, humoral immune response, or T cell-mediated immune responses.

CONCLUSIONS

We identified five hub genes associated with the NSCLC tumorigenesis. NSCLC patients with higher expressions of each hub gene had a worse prognosis than those with lower expressions. Moreover, the hub genes might serve as biomarkers and therapeutic targets for precise diagnosis, target therapy, and immunotherapy of NSCLC in the future.

UBE2S promotes the progression and Olaparib resistance of ovarian cancer through Wnt/β-catenin signaling pathway

BACKGROUND

Ovarian cancer is the most lethal gynecologic malignancy worldwide. Olaparib, an inhibitor of poly (ADP-ribose) polymerase (PARP), is becoming widely used in ovarian cancer treatment. The overall survival of ovarian cancer has not been significantly changed over the past decades and ovarian cancer has become increasingly resistant to the Olaparib. Ubiquitin-conjugating enzyme E2S (UBE2S) has been proved to promote malignant behaviors in many cancers. However, the function of UBE2S in the development and Olaparib resistance of ovarian cancer are unclear.

MATERIALS AND METHODS

In this study, we detected the expression of UBE2S in normal fallopian tube (FT) and HGSOC tissues. A2780 and SKOV3 cells were stably transfected with PCMV-UBE2S, PCMV-UBE2S-C95S, UBE2S shRNAs, and negative controls. The CCK8 assay and clonogenic assay were conducted to analyze ovarian cancer proliferation and Olaparib resistance. The transwell assay was performed to determine the migration and invasion of ovarian cancer cells. The relative protein levels of the Wnt/β-catenin signaling pathway were tested using western blot. The ovarian cancer cells were treated with XAV-939 to investigate the role of Wnt/β-catenin signaling pathway in Olaparib resistance. Moreover, we repeated some above procedures in the xenograft model.

RESULTS

The results demonstrated that UBE2S was highly upregulated in HGSOC and that high UBE2S expression was correlated with poor outcomes in HGSOC. UBE2S promoted ovarian cancer proliferation and drived the migration and invasion of ovarian cancer cells. UBE2S activated the Wnt/β-catenin signaling pathway in ovarian cancer resulting in Olaparib resistance in vitro and in vivo. Furthermore, UBE2S enhanced the proliferation and Olaparib resistance of ovarian cancer in its enzymatic activity dependent manner.

CONCLUSIONS

These data suggest a possible molecular mechanism of proliferation and metastasis of ovarian cancer and highlight the potential role of UBE2S as a therapeutic target in ovarian cancer.

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.

Overexpression of UBE2M through Wnt/β-Catenin signaling is associated with poor prognosis and chemotherapy resistance in colorectal cancer

Background

The expression of ubiquitin-conjugating enzyme E2 M (UBE2M) is elevated in colorectal carcinoma (CRC). However, the underlying mechanisms and effects of UBE2M on the prognosis and drug resistance in CRC have not been investigated.

Methods

CRC specimens and adjacent normal tissues were collected from 74 patients. The expression of UBE2M was measured by quantitative real-time polymerase chain reaction (PCR) and immunohistochemistry. Multivariable cox regression analysis was used to analyze the risk factors for overall survival in clinical CRC patients. Human colorectal cancer cell lines HCT116 and SW480 were transfected with specific UBE2M small interfering ribonucleic acid (siRNA) or plasmid to either suppress or increase the expression of UBE2M for in vitro experiments. Also, chemotherapy-resistant HCT116 and SW480 cells were established by being treated with increasingly higher concentrations of fluorouracil (5-FU) or oxaliplatin. XAV-939 was used as a wingless/integrated-beta-catenin (Wnt/β-catenin) signaling inhibitor.

Results

According to quantitative real-time PCR and immunohistochemistry, the expression of UBE2M was elevated in CRC tissues compared to normal tissues. Based on cox regression analysis, the overexpression of UBE2M was a risk factor for overall survival of CRC patients. The expression of UBE2M was notably high in 5-FU- and oxaliplatin-resistant cells in in vitro experiments. Also, cells transfected with specific UBE2M siRNA or plasmid induced lower resistance to 5-FU and higher resistance to oxaliplatin. Finally, the expression of β-catenin was correlated with the expression of UBE2M in transfected cells and treatment with XAV939 decreased the degree of drug resistance in chemotherapy-resistant HCT116 cells.

Conclusions

Overexpression of UBE2M in CRC specimens contributes to a decreased overall survival of patients and mediates 5-FU and oxaliplatin resistance in CRC cells via the Wnt/β-catenin signaling pathway.