USP4 expression independently predicts favorable survival in lung adenocarcinoma

Ubiquitin-specific protease 54 regulates GLUT1-mediated aerobic glycolysis to inhibit lung adenocarcinoma progression by modifying p53 degradation

Lung adenocarcinoma (LUAD) is one of the most prevalent types of cancer. Ubiquitination is crucial in modulating cell proliferation and aerobic glycolysis in cancer. The frequency of TP53 mutations in LUAD is approximately 50%. Currently, therapeutic targets for wild-type (WT) p53-expressing LUAD are limited. In the present study, we systemically explored the expression of ubiquitin-specific protease genes using public datasets. Then, we focused on ubiquitin-specific protease 54 (USP54), and explored its prognostic significance in LUAD patients using public datasets, analyses, and an independent cohort from our center. We found that the expression of USP54 was lower in LUAD tissues compared with that in the paracancerous tissues. Low USP54 expression levels were linked to a malignant phenotype and worse survival in patients with LUAD. The results of functional experiments revealed that up-regulation of USP54 suppressed LUAD cell proliferation in vivo and in vitro. USP54 directly interacted with p53 protein and the levels of ubiquitinated p53 were inversely related to USP54 levels, consistent with a role of USP54 in deubiquitinating p53 in p53-WT LUAD cells. Moreover, up-regulation of the USP54 expression inhibited aerobic glycolysis in LUAD cells. Importantly, we confirmed that USP54 inhibited aerobic glycolysis and the growth of tumor cells by a p53-mediated decrease in glucose transporter 1 (GLUT1) expression in p53-WT LUAD cells. Altogether, we determined a novel mechanism of survival in the p53-WT LUAD cells to endure the malnourished tumor microenvironment and provided insights into the role of USP54 in the adaptation of p53-WT LUAD cells to metabolic stress.

High USP4 mRNA is associated with an HPV-positive status in head and neck squamous cell carcinoma patients

INTRODUCTION

Head and neck squamous cell carcinoma (HNSCC) is among the most common cancers in the world with a low survival rate and common diagnosis at late stages. Deubiquitination of proteins is involved in tumor growth, metastasis, apoptosis, and immunosuppressive pathways. The impact of the ubiquitin-specific protease (USP4) on survival was only scarcely investigated so far. The goal of our research was to analyze the association of USP4 expression with prognosis and clinicopathological features in HNSCC.

METHODS

USP4 mRNA levels were derived from The Cancer Genome Atlas (TCGA) for a cohort of 510 patients. Protein expression of USP4 was analyzed by immunohistochemistry in a second cohort of 113 patients. Associations between USP4 levels and overall survival, disease-free survival and clinicopathological data were analyzed.

RESULTS

High levels of USP4 mRNA were associated with prolonged overall survival in univariable analysis. There was no more association with survival after correction for the confounders HPV, stage and smoker status. High USP4 mRNA levels were linked to a lower T-stage, the patient's age at diagnosis, and a positive HPV status. USP4 protein levels were not associated with prognosis or other features.

CONCLUSION

Since high USP4 mRNA was not an independent prognostic marker, we assume that the association is a result of the correlation of high USP4 mRNA with an HPV-positive status. Therefore, further investigation of USP4 mRNA and its association with the HPV status of HNSCC patients is warranted.

MIR99AHG inhibits EMT in pulmonary fibrosis via the miR-136-5p/USP4/ACE2 axis

Background

Long non-coding RNAs (lncRNAs) are closely related to the occurrence and development of cancer. Abnormally expressed lncRNA can be used as a diagnostic marker for cancer. In this study, we aim to investigate the clinical significance of MIR99AHG expression in lung adenocarcinoma (LUAD), and its biological roles in LUAD progression.

Methods

The relative expression of MIR99AHG in LUAD tissues and cell lines was analyzed using public databases and RT-qPCR. The biological functions of MIR99AHG were investigated using a loss-of-function approach. The effect of MIR99AHG on lung fibrosis was assessed by scratch assay, invasion assay and lung fibrosis rat model. FISH, luciferase reporter assay and immunofluorescence were performed to elucidate the underlying molecular mechanisms.

Results

LncRNA MIR99AHG expression level was downregulated in LUAD tissues and cell lines. Low MIR99AHG levels were associated with poorer patient overall survival. Functional analysis showed that MIR99AHG is associated with the LUAD malignant phenotype in vitro and in vivo. Further mechanistic studies showed that, MIR99AHG functions as a competitive endogenous RNA (ceRNA) to antagonize miR-136-5p-mediated ubiquitin specific protease 4 (USP4) degradation, thereby unregulated the expression of angiotensin-converting enzyme 2 (ACE2), a downstream target gene of USP4, which in turn affected alveolar type II epithelial cell fibrosis and epithelial–mesenchymal transition (EMT). In summary, the MIR99AHG/miR-136-5p/USP4/ACE2 signalling axis regulates lung fibrosis and EMT, thus inhibiting LUAD progression.

Conclusion

This study showed that downregulated MIR99AHG leads to the development of pulmonary fibrosis. Therefore, overexpression of MIR99AHG may provide a new approach to preventing LUAD progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03633-y.

Deubiquitinating enzymes USP4 and USP17 finetune the trafficking of PDGFRβ and affect PDGF-BB-induced STAT3 signalling

Interaction of platelet-derived growth factor (PDGF) isoforms with their receptors results in activation and internalization of receptors, with a concomitant activation of downstream signalling pathways. Ubiquitination of PDGFRs serves as a mark to direct the internalization and sorting of the receptors. By overexpressing a panel of deubiquitinating enzymes (DUBs), we found that USP17 and USP4 efficiently deubiquitinate PDGF receptor β (PDGFRβ) and are able to remove both Lys63 and Lys48-linked polyubiquitin chains from the receptor. Deubiquitination of PDGFRβ did not affect its stability, but regulated the timing of its trafficking, whereby USP17 prolonged the presence of the receptor at the cell surface, while USP4 affected the speed of trafficking towards early endosomes. Induction of each of the DUBs in BJhTERT fibroblasts and U2OS osteosarcoma cells led to prolonged and/or shifted activation of STAT3 in response to PDGF-BB stimulation, which in turn led to increased transcriptional activity of STAT3. Induction of USP17 promoted acute upregulation of the mRNA expression of STAT3-inducible genes STAT3, CSF1, junB and c-myc, while causing long-term changes in the expression of myc and CDKN1A. Deletion of USP17 was lethal to fibroblasts, while deletion of USP4 led to a decreased proliferative response to stimulation by PDGF-BB. Thus, USP17- and USP4-mediated changes in ubiquitination of PDFGRβ lead to dysregulated signalling and transcription downstream of STAT3, resulting in defects in the control of cell proliferation.

Advances in deubiquitinating enzymes in lung adenocarcinoma

The process of ubiquitination and deubiquitination is widely present in the human body's protein reactions and plays versatile roles in multiple diseases. Deubiquitinating enzymes (DUBs) are significant regulators of this process, which cleave the ubiquitin (Ub) moiety from various substrates and maintain protein stability. Lung adenocarcinoma (LUAD) is the most common type of non-small cell lung cancer (NSCLC) and remains refractory to treatment. To elucidate the mechanism of LUAD and advance new therapeutic targets, we review the latest research progress on DUBs in LUAD. We summarize the biological capabilities of these DUBs and further highlight those DUBs that may serve as anticancer target candidates for precision treatment. We also discuss deubiquitinase inhibitors, which are expected to play a role in targeted LUAD therapy.

Spotlight on USP4: Structure, Function, and Regulation

The deubiquitinating enzyme (DUB)–mediated cleavage of ubiquitin plays a critical role in balancing protein synthesis and degradation. Ubiquitin-specific protease 4 (USP4), a member of the largest subfamily of cysteine protease DUBs, removes monoubiquitinated and polyubiquitinated chains from its target proteins. USP4 contains a DUSP (domain in USP)–UBL (ubiquitin-like) domain and a UBL-insert catalytic domain, sharing a common domain organization with its paralogs USP11 and USP15. USP4 plays a critical role in multiple cellular and biological processes and is tightly regulated under normal physiological conditions. When its expression or activity is aberrant, USP4 is implicated in the progression of a wide range of pathologies, especially cancers. In this review, we comprehensively summarize the current knowledge of USP4 structure, biological functions, pathological roles, and cellular regulation, highlighting the importance of exploring effective therapeutic interventions to target USP4.

What deubiquitinating enzymes, oncogenes, and tumor suppressors actually do: Are current assumptions supported by patient outcomes?

Context can determine whether a given gene acts as an oncogene or a tumor suppressor. Deubiquitinating enzymes (DUBs) regulate the stability of many components of the pathways dictating cell fate so it would be expected that alterations in the levels or activity of these enzymes may have oncogenic or tumor suppressive consequences. In the current review we survey publications reporting that genes encoding DUBs are oncogenes or tumor suppressors. For many DUBs both claims have been made. For such "double agents," the effects of gain or loss of function will depend on the overall status of a complex of molecular signaling networks subject to extensive crosstalk. As the TGF-β paradox makes clear context is critical in cell fate decisions, and the disconnect between experimental findings and patient survival outcomes can in part be attributed to disparities between culture conditions and the microenvironment in vivo. Convincing claims for oncogene or tumor suppressor roles require the documentation of gene alterations in patient samples; survival curves are alone inadequate.

SOX2-Upregulated microRNA-30e Promotes the Progression of Esophageal Cancer via Regulation of the USP4/SMAD4/CK2 Axis

Esophageal cancer (EC) is a highly aggressive disease, and its progression involves a complex gene regulation network. Transcription factor SOX2 is amplified in various cancers including EC. A pathway involving SOX2 regulation of microRNAs (miRNAs) and their target genes has been previously revealed. This study aims to delineate the ability of SOX2 to influence the EC progression, with the involvement of miR-30e/USP4/SMAD4/CK2 axis. SOX2 expression was first examined in the clinical tissue samples from 30 EC patients. Effects of SOX2 on proliferation, migration, and invasion alongside tumorigenicity of transfected cells were examined by means of gain- and loss-of-function experiments. EC tissues and cells exhibited high expression of SOX2, miR-30e, and CK2 and poor expression of USP4 and SMAD4. Mechanistically, SOX2 was positively correlated with miR-30e and upregulated the expression of miR-30e. miR-30e specifically targeted USP4, which induced deubiquitination of SMAD4 and promoted its expression. Meanwhile, SMAD4 was enriched in the CK2 promoter region and thus inhibited its expression. SOX2 stimulated EC cell proliferative, invasive, and migratory capacities in vitro and tumor growth in vivo by regulating the miR-30e/USP4/SMAD4/CK2 axis. Collectively, our work reveals a novel SOX2-mediated regulatory network in EC that may be a viable target for EC treatment.

Ubiquitin-specific protease 4 predicts an unfavorable prognosis and promotes malignant behaviors in vitro in pancreatic cancer

Ubiquitin-specific protease 4 (USP4), has been reported to participate in the progression of various cancers due to its role in post-translational modulation. However, the prognostic significance and mechanism of USP4 in pancreatic cancer (PC) have not been well elucidated before. In the present study, we found that USP4 expression was higher in PC tissues than that in adjacent normal tissues and PC patients with high level of USP4 expression have a poor prognosis via immunohistochemistry and bioinformatics analyses. In vitro study showed that knockdown of USP4 inhibited PC cells proliferation, migration and invasion. Mechanistically, USP4 can activate nuclear factor kappa-B signaling pathway via stabilizing TNF receptor associated factor 6 at its protein level to promote the ability of proliferation, migration and invasion of PC cells. The results of this study revealed that USP4 plays a tumor-promoting role in PC and can be used as a prognostic indicator and therapeutic target for patients with resected PC.

USP4 function and multifaceted roles in cancer: a possible and potential therapeutic target

Cancer remains one of the major culprits causing disease-related deaths and leads to a high morbidity and similar mortality. Insidious onset, difficult early detection and a lack of broad-spectrum and effective multi-cancer therapeutic targets have limited the prolongation of cancer patients’ survival for decades. Therefore, a versatile therapeutic target which is involved in various cancer-related signaling pathways and different cancers may be more effective for cancer targeted therapy. USP4, one of the DUBs members which participates in deubiquitination, an inverse process of ubiquitination, can regulate various classical cancer-related signaling pathways, and thereby plays a vital role in some pathological and physiological processes including tumor initiation and progression. Recently, USP4 has been found to exert versatile influences on cells proliferation, migration and invasion, also apoptosis of various tumors. Moreover, USP4 can also act as a prognostic biomarker in several cancers. This review will give a comprehensive introduction of USP4 about its regulatory mechanisms, related signaling pathways, pathophysiological functions and the roles in various cancers which may help us better understand its biological functions and improve future studies to construct suitable USP4-targeted cancer therapy system.

The role of deubiquitinating enzymes in cancer drug resistance

Drug resistance is a well-known phenomenon leading to a reduction in the effectiveness of pharmaceutical treatments. Resistance to chemotherapeutic agents can involve various intrinsic cellular processes including drug efflux, increased resistance to apoptosis, increased DNA damage repair capabilities in response to platinum salts or other DNA-damaging drugs, drug inactivation, drug target alteration, epithelial-mesenchymal transition (EMT), inherent cell heterogeneity, epigenetic effects, or any combination of these mechanisms. Deubiquitinating enzymes (DUBs) reverse ubiquitination of target proteins, maintaining a balance between ubiquitination and deubiquitination of proteins to maintain cell homeostasis. Increasing evidence supports an association of altered DUB activity with development of several cancers. Thus, DUBs are promising candidates for targeted drug development. In this review, we outline the involvement of DUBs, particularly ubiquitin-specific proteases, and their roles in drug resistance in different types of cancer. We also review potential small molecule DUB inhibitors that can be used as drugs for cancer treatment.

Development and validation of a 4-gene combination for the prognostication in lung adenocarcinoma patients

Objective: To identify a multi-gene prognostic factor in patients with lung adenocarcinoma (LUAD).

Materials and methods Prognosis-related genes were screened in the TCGA-LUAD cohort. Then, patients in this cohort were randomly separated into training set and test set. Least absolute shrinkage and selection operator (LASSO) regression was performed to the penalized the Cox proportional hazards regression (CPH) model on the training set, and a prognostication combination based on the result of LASSO analysis was developed. By performing Kaplan-Meier curve analysis, univariate and multivariable CPH model on the overall survival (OS) as well as recurrence free survival (RFS), the prognostication performance of the multigene combination were evaluated. Moreover, we constructed a nomogram and performed decision curve analysis to evaluate the clinical application of the multigene combination.

Results We obtained 99 prognosis-related genes and screened out a 4-gene combination (including CIDEC, ZFP3, DKK1, and USP4) according to the LASSO analysis. The results of survival analyses suggested that patients in the 4-gene combination low-risk group had better OS and RFS than those in the 4-gene combination high-risk group. The 4-gene mentioned was demonstrated to be independent prognostic factor of patients with LUAD in the training set(OS, HR=11.962, P<0.001; RFS, HR=9.281, P<0.001) and test set (OS, HR=5.377, P=0.003; RFS, HR=2.949, P=0.104). More importantly, its prognosis performance was well in the validation set (OS, HR=0.955, P=0.002; RFS, HR=1.042, P<0.001).

Conclusions We introduced a 4-gene combination which could predict the survival of LUAD patients and might be an independent prognostic factor in LUAD.

Epigenetic Silencing of Ubiquitin Specific Protease 4 by Snail1 Contributes to Macrophage-Dependent Inflammation and Therapeutic Resistance in Lung Cancer

There is a positive feedback loop driving tumorigenesis and tumor growth through coordinated regulation of epigenetics, inflammation, and stemness. Nevertheless, the molecular mechanism linking these processes is not well understood. In this study, we analyzed the correlation of de-ubiquitinases (DUBs) expression with survival data from the OncoLnc database. Among the DUBs analyzed, ubiquitin specific protease 4 (USP4) had the lowest negative Cox coefficient. Low expression of USP4 was associated with poor survival among lung cancer patients and was inversely correlated with expression of stemness and inflammation markers. Expression of USP4 were reduced at more advanced stages of lung cancer. Mechanistically, expression of USP4 was downregulated in snail1-overexpressing and stemness-enriched lung cancer cells. Snail1 was induced in lung cancer cells by interaction with macrophages, and epigenetically suppressed USP4 expression by promoter methylation. Stable knockdown of USP4 in lung cancer cells enhanced inflammatory responses, stemness properties, chemotherapy resistance, and the expression of molecules allowing escape from immunosurveillance. Further, mice injected with USP4 knockdown lung cancer cells demonstrated enhanced tumorigenesis and tumor growth. These results reveal that the Snail1-mediated suppression of USP4 is a potential mechanism to orchestrate epigenetic regulation, inflammation and stemness for macrophage-promoted tumor progression.

Targeting the circBMPR2/miR-553/USP4 Axis as a Potent Therapeutic Approach for Breast Cancer

Emerging evidence suggests that circular RNAs (circRNAs) have crucial roles in various processes, including cancer development and progression. However, the functional roles of circRNAs in breast cancer remain to be elucidated. In this study, we identified a novel circRNA (named circBMPR2) whose expression was lower in breast cancer tissues with metastasis. Moreover, circBMPR2 expression was negatively associated with the motility of breast cancer cells and significantly downregulated in human breast cancer tissues. Functionally, we found that circBMPR2 knockdown effectively enhanced cell proliferation, migration, and invasion. Moreover, circBMPR2 knockdown promoted tamoxifen resistance of breast cancer cells through inhibiting tamoxifen-induced apoptosis, whereas circBMPR2 overexpression led to decreased tamoxifen resistance. Mechanistically, we demonstrated that circBMPR2 could abundantly sponge miR-553 and that miR-553 overexpression could attenuate the inhibitory effects caused by circBMPR2 overexpression. We also found that ubiquitin-specific protease 4 (USP4) was a direct target of miR-553, which functions as a tumor suppressor in breast cancer. Our findings demonstrated that circBMPR2 might function as a miR-553 sponge and then relieve the suppression of USP4 to inhibit the progression and tamoxifen resistance of breast cancer. Targeting this newly identified circRNA may help us to develop potential novel therapies for breast cancer patients.

USP4 deficiency exacerbates hepatic ischaemia/reperfusion injury via TAK1 signalling

Ubiquitin-specific peptidase 4 (USP4) protein is a type of deubiquitination enzyme that is correlated with many important biological processes. However, the function of USP4 in hepatic ischaemia/reperfusion (I/R) injury remains unknown. The aim of the present study was to explore the role of USP4 in hepatic I/R injury. USP4 gene knockout mice and primary hepatocytes were used to construct hepatic I/R models. The effect of USP4 on hepatic I/R injury was examined via pathological and molecular analyses. Our results indicated that USP4 was significantly up-regulated in liver of mice subjected to hepatic I/R injury. USP4 knockout mice exhibited exacerbated hepatic I/R injury, as evidenced by enhanced liver inflammation via the nuclear factor κB (NF-κB) signalling pathway and increased hepatocyte apoptosis. Additionally, USP4 overexpression inhibited hepatocyte inflammation and apoptosis on hepatic I/R stimulation. Mechanistically, our study demonstrates that USP4 deficiency exerts its detrimental effects on hepatic I/R injury by inducing activation of the transforming growth factor β-activated kinase 1 (TAK1)/JNK signalling pathways. TAK1 was required for USP4 function in hepatic I/R injury as TAK1 inhibition abolished USP4 function in vitro In conclusion, our study demonstrates that USP4 deficiency plays a detrimental role in hepatic I/R injury by promoting activation of the TAK1/JNK signalling pathways. Modulation of this axis may be a novel strategy to alleviate the pathological process of hepatic I/R injury.