Deubiquitylating Enzymes in Cancer and Immunity

FBXL18 promotes endometrial carcinoma progression via destabilizing DUSP16 and thus activating JNK signaling pathway

OBJECTIVE

The therapeutic options for patients with advanced endometrial carcinoma (EC) were still limited and the prognosis remained unfavorable. F-box and leucine-rich repeat protein 18 (FBXL18), belonging to the F-box protein family, was frequently altered in human cancer, while its functional role and underlying mechanisms in EC were largely unexplored.

METHODS

The expression of FBXL18 in EC tissues and cells were explored using data mining strategies and further experiments. Multiple in vitro assays, including CCK-8, colony formation, wound healing, and Transwell invasion assays, were performed to assess the function of FBXL18 on cell proliferation, migration, and invasion. Bioinformatic analyses, western blot, qRT-PCR, Co-immunoprecipitation and ubiquitination assays were employed to identify the downstream pathway and direct substrate of FBXL18.

RESULTS

FBXL18 was highly expressed in EC tissues and cell lines, and EC patients with high FBXL18 expression had poor clinical outcome. Loss- and gain-of-function assays showed that silencing FBXL18 suppressed EC cell proliferation, migration, and invasion, while overexpressing FBXL18 caused the opposite effects. Mechanistically, FBXL18 could physically interacted with DUSP16, a dual specificity phosphatase, leading to its ubiquitination and degradation, and thus activating JNK signaling pathway. Upregulation of DUSP16 in EC cells alleviated FBXL18 overexpression-induced activation of JNK signaling pathway, and reversed FBXL18 overexpression-mediated enhanced cell capacities of proliferation, migration, and invasion.

CONCLUSION

In summary, our study had showcased the elevated expression, prognostic prediction performance, and the malignant tumor-promoting role of FBXL18 in EC. The novel mechanisms underlying this phenotype are that FBXL18 promotes the ubiquitination and degradation of DUSP16, and thus activates JNK/c-JUN signaling to facilitate EC progression.

OTUD3 inhibits breast cancer cell metastasis by regulating TGF-β pathway through deubiquitinating SMAD7

BACKGROUND

Breast cancer (BRCA) is the most common malignant tumor in women, and distant metastasis is an important cause of death. Epithelial mesenchymal transition (EMT) is an important factor in tumor cell metastasis, in which TGF-β signaling pathway plays an important role. SMAD7 can inhibit TGF-β pathway. Previously, we found that ovarian tumor domain-containing protein 3(OTUD3) could maintain the stability of multiple molecules through deubiquitination. In this study, multiple experiments were conducted to verify whether OTUD3 can inhibit TGF-β pathway by deubiquitinating SMAD7.

METHODS

Firstly, bioinformatics was used to search the expression of OTUD3 in breast cancer and its correlation with SMAD7 in the TCGA database. The correlation between the protein and mRNA expression levels of OTUD3 and SMAD7 in multiple BRCA cell lines was verified. Also, the OTUD3 and SMAD7 expression in human BRCA samples and its influence on prognosis were verified by immunohistochemical experiments. Then, the CO-IP experiment was performed by transfecting OTUD3 and SMAD7 in HEK293T cells to confirm whether OTUD3 could maintain SMAD7 protein stability through deubiquitination. Furthermore, luciferase reporting assay, in vitro protein interaction, and transwell assay were used to verify whether OTUD3 could inhibit TGF-β pathway by deubiquitinating SMAD7 and affect cell invasion. Western blot and RT-qPCR were used to detect the correlation between OTUD3 and molecules regulated by the TGF-β pathway. Finally, the effect of OTUD3 on tumor cells was determined by 3D matrigel cell culture.

RESULTS

The expression of OTUD3 was low in BRCA and positively correlated with SMAD7. Cytological experiments and immunohistochemistry confirmed that OTUD3 was positively correlated with the expression of SMAD7, and the patients with a low expression of OTUD3 had a short recurrence-free survival (RFS). Cell experiments confirmed that OTUD3 could regulate the TGF-β pathway by deubiquitinating SMAD7, which affected EMT and inhibited cell invasion. OTUD3 was found to inhibit the stemness of tumor cells by 3D matrigel cell culture.

CONCLUSIONS

Our findings indicated OTUD3 inhibited BRCA metastasis associated with TGF-β signaling by deubiquitination to stabilize SMAD7 protein levels.

Viral oncogenesis in cancer: from mechanisms to therapeutics

The year 2024 marks the 60th anniversary of the discovery of the Epstein-Barr virus (EBV), the first virus confirmed to cause human cancer. Viral infections significantly contribute to the global cancer burden, with seven known Group 1 oncogenic viruses, including hepatitis B virus (HBV), human papillomavirus (HPV), EBV, Kaposi sarcoma-associated herpesvirus (KSHV), hepatitis C virus (HCV), human T-cell leukemia virus type 1 (HTLV-1), and human immunodeficiency virus (HIV). These oncogenic viruses induce cellular transformation and cancer development by altering various biological processes within host cells, particularly under immunosuppression or co-carcinogenic exposures. These viruses are primarily associated with hepatocellular carcinoma, gastric cancer, cervical cancer, nasopharyngeal carcinoma, Kaposi sarcoma, lymphoma, and adult T-cell leukemia/lymphoma. Understanding the mechanisms of viral oncogenesis is crucial for identifying and characterizing the early biological processes of virus-related cancers, providing new targets and strategies for treatment or prevention. This review first outlines the global epidemiology of virus-related tumors, milestone events in research, and the process by which oncogenic viruses infect target cells. It then focuses on the molecular mechanisms by which these viruses induce tumors directly or indirectly, including the regulation of oncogenes or tumor suppressor genes, induction of genomic instability, disruption of regular life cycle of cells, immune suppression, chronic inflammation, and inducing angiogenesis. Finally, current therapeutic strategies for virus-related tumors and recent advances in preclinical and clinical research are discussed.

The combination of USP24-i-101-Astemizole sensitizes the cytotoxicity of Taxol and Gefitinib in drug-resistant lung cancer

In this study, we utilized the yeast two-hybrid system to screen for proteins interacting with USP24. Out of 250 such proteins, functional enrichment analysis using MetaCore™ indicated that 33 of them were involved in lung cancer progression. We then investigated gene expression and survival rates of these 33 proteins in lung cancer patients and cell lines through TCGA databases, Kaplan-Meier Plotter databases, and RNA-seq profile from A549/A549-T24 cells. By employing the patients' survival rate and gene expression profile of these 33 USP24-interacting proteins as gene signatures, we identified 10 potential drugs for inhibiting lung cancer progression or drug resistance via drug repurposing strategy using the Connectivity Map (CMap) database. Of these 10 drugs, six showed similar indicators in Clinical Trials, while the other four candidates (15-delta prostaglandin J2, Astemizole, Trifluoperazine, and 1,4-chrysenequinone) were chosen to evaluate their effect on re-sensitizing cytotoxicity of Taxol and Gefitinib in drug-resistant cancer cells. Experiments demonstrated that treatment with USP24-i-101 and Astemizole alone significantly inhibited drug resistance and re-sensitized the cytotoxicity of Taxol and Gefitinib in drug-resistant lung cancer cells. Notably, combination therapy with USP24-i-101and Astemizole re-sensitized the cytotoxicity of Taxol and Gefitinib in drug-resistant lung cancer, which could benefit in inhibiting drug resistance during cancer therapy.

The role of deubiquitinases in cardiovascular diseases: mechanisms and therapeutic implications

Cardiovascular diseases (CVDs) have become the leading cause of death globally, surpassing infectious diseases and other chronic illnesses. The incidence and mortality rates of CVDs are rising worldwide, posing a key challenge in public health. The ubiquitination system is a vast and complex. It is an important post-translational modification that plays a crucial role in various cellular processes. Deubiquitination is catalyzed by deubiquitinases (DUBs), which remove ubiquitin (Ub) from ubiquitinated proteins, thereby reversing the ubiquitination process. DUBs play an important role in many biological processes, such as DNA repair, cell metabolism, differentiation, epigenetic regulation, and protein stability control. They also participate in the regulation of many signaling pathways associated with the development and progression of CVDs. In this review, we primarily focus on the role of DUBs in various key pathological mechanisms of atherosclerosis (AS), such as foam cell formation, vascular remodeling (VR), endothelial-to-mesenchymal transition (End-MT), and clonal hematopoiesis (CH). In the heart, we summarize the involvement of DUBs in diseases and pathological processes, including heart failure (HF), myocardial infarction (MI), myocardial hypertrophy (MH) and ischemia/reperfusion (I/R) injury. Additionally, we also explore the diabetic cardiomyopathy (DCM) and the use of doxorubicin-induced cardiotoxicity in clinical settings. A comprehensive understanding of deubiquitination may provide new insights for the treatment and drug design of CVDs.

Ubiquitin-specific protease 13 regulates FcεRI-mediated mast cell activation and allergic inflammation via SYK protein modulation

Mast cells (MCs) are therapeutic targets for high-affinity IgE Fc receptors (FcεRI)-mediated allergic responses. Deubiquitinating enzymes (DUBs), including ubiquitin-specific protease 13 (USP13), are involved in multiple inflammatory processes. This study aims to reveal USP13's role in FcεRI-mediated MC activation and its underlying mechanisms. Our results showed USP10/13 inhibitor spautin-1 inhibited IgE-mediated MC activation, as evidenced by a reduction in the release of β-hexosaminidase (β-hex) and histamine and decreased expression and secretion of inflammatory cytokines. Spautin-1 also attenuated inflammatory processes in IgE-mediated passive cutaneous anaphylaxis (PCA) and ovalbumin (OVA)-induced active systemic anaphylaxis (ASA) models. Furthermore, knockdown of USP13 by short hairpin (sh)RNA diminished IgE-induced MC activation. Protein-protein interactions assays showed that USP13 interacted with the co-immunoprecipitated protein spleen tyrosine kinase (SYK) and deubiquitinated SYK. USP13 bound the kinase domain of SYK and removed its K63-linked polyubiquitination chain, yielding a more stable SYK protein. Importantly, 2-methoxyestradiol (2-Meth) was identified as a potential inhibitor of USP13 and inhibited FcεRI-mediated MC activation effectively in vitro and in vivo. In conclusion, it elucidated the molecular mechanism by which USP13 regulated SYK stability in MCs. The USP13-SYK axis may serve as a therapeutic target for treating FcεRI-mediated activation of MCs and associated inflammatory responses.

The Role of Ubiquitination on Macrophages in Cardiovascular Diseases and Targeted Treatment

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide, with macrophage dysfunction playing a central role in its pathogenesis. Ubiquitination, a critical post-translational modification, regulates diverse macrophage functions, including lipoprotein metabolism, inflammation, oxidative stress, mitophagy, autophagy, efferocytosis, and programmed cell death (pyroptosis, necroptosis, ferroptosis, and apoptosis). This review highlights the regulatory roles of ubiquitination in macrophage-driven CVD progression, focusing on its effects on cholesterol metabolism, inflammation, activation, polarization, and the survival of macrophages. Targeting ubiquitination pathways has therapeutic potential by enhancing macrophage autophagy, reducing inflammation, and improving plaque stability. However, challenges, such as off-target effects, ubiquitination crosstalk, and macrophage heterogeneity, must be addressed. By integrating advances in ubiquitination biology, therapeutic strategies can be developed to mitigate CVD and other macrophage-driven inflammatory diseases. This review underscores the potential of ubiquitination-targeting therapies for mitigating CVD and highlights the key areas for further investigation.

Emerging role of deubiquitinases in modulating cancer chemoresistance

Chemotherapy remains a gold standard in cancer treatment by targeting the rapidly dividing cancer cells. However, chemoresistance is a major obstacle to successful cancer treatment, often leading to recurrence, metastasis, and high mortality. Deubiquitinases (DUBs), enzymes that remove ubiquitin and stabilize proteins, have been implicated in chemoresistance and can either promote therapeutic resistance or enhance sensitivity depending on their targets. In this review, we highlight the chemoresistance mechanisms of DUBs in various cancers, including breast, lung, liver, gastrointestinal, colorectal, ovarian, prostate, and blood cancers. Given these mechanisms, the development of DUB inhibitors has gained considerable attention in cancer therapeutics and combination therapies involving these inhibitors show potential to overcome drug resistance and improving treatment outcomes.

Targeting USP1 Potentiates Radiation-Induced Type I IFN-Dependent Antitumor Immunity by Enhancing Oligo-Ubiquitinated SAR1A-Mediated STING Trafficking and Activation

The magnitude of Type I interferon (IFN) mediated innate immune response within the tumor microenvironment (TME) critically influences the effectiveness of radiotherapy. Unfortunately, due to a myriad of resistance mechanisms, the double-stranded DNA (dsDNA) signals produced by tumor cells postradiotherapy often induce a diminished response from immune cells. Through chemical screening targeting deubiquitinating enzymes, we identified USP1 (Ubiquitin Specific Peptidase 1) inhibitor as an enhancer of post-radiotherapy dsDNA responses. Mechanistically, within the context of immune-stimulatory cells in TME, USP1 serves as a suppressor in the stress-mediated stages of the cGAS (Cyclic GMP-AMP synthase) -STING (Stimulator of interferon genes protein) signaling pathway, specifically affecting the trafficking of STING from endoplasmic reticulum to Golgi apparatus. It is elucidated that SAR1A (Secretion associated Ras related GTPase 1A) requires K27-linked oligo-ubiquitination to assemble the STING-COP-II (Coat protein II) transport complex for STING trafficking. USP1 counteracts this activation by removing SAR1A ubiquitination, thereby blocking STING trafficking and activation. Consequently, pharmacological USP1 inhibition using ML323 sustains SAR1A ubiquitination and COP-II complex formation, significantly enhancing STING trafficking and subsequent Type I IFN production. This intervention substantially amplifies radiotherapy-induced immune activation in the TME, providing a strategic approach to overcome therapeutic resistance and synergize radiotherapy with immunotherapies.

Deubiquitinase USP18 mediates cell migration, apoptosis and ferroptosis in lung adenocarcinoma by depending on POU4F1/PRKAA2 axis

BACKGROUND

Lung adenocarcinoma (LUAD) is a common type of lung cancer and its pathogenic mechanism is complicated. A profound research for the molecular mechanism in LUAD is indispensable.

METHODS

Gene levels were detected via real-time quantitative polymerase chain reaction and western blot. Proliferation, migration and apoptosis were assessed using colony formation assay, wound healing assay, and flow cytometry. Ferroptosis was evaluated through oxidative stress and iron level. Relations between genes were analyzed using Immunoprecipitation (IP) assay and ubiquitination assay, as well as ChIP assay and dual-luciferase reporter assay. USP18 function in vivo was explored using xenograft model.

RESULTS

Ubiquitin-specific protease 18 (USP18) was overexpressed in LUAD tissues and cells. LUAD cell proliferation and migration were suppressed but apoptosis and ferroptosis were enhanced after USP18 knockdown. Pou domain, class 4, transcription factor 1 (POU4F1) protein expression was stabilized through USP18-mediated deubiquitination. Function of USP18 silence was reversed by POU4F1 overexpression in LUAD cells. POU4F1 promoted transcription of AMPK-α2 (PRKAA2) and USP18 modulated PRKAA2 protein level via affecting POU4F1. POU4F1 regulated LUAD cell behaviors by upregulating PRKAA2. USP18 enhanced tumor growth in vivo via mediating POU4F1 and PRKAA2.

CONCLUSION

All data demonstrated that USP18 acted as an oncogene in LUAD via interacting with POU4F1/PRKAA2 axis.

USP5 Suppresses Ferroptosis in Bladder Cancer Through Stabilization of GPX4

USP5 has been proven to play an important role in the proliferation of bladder cancer (BC). In this study, we focused on investigating the molecular mechanism of ferroptosis induced by USP5 in bladder cancer. The role of USP5 in bladder cancer was evaluated using T24 wild-type cells (WT) and USP5 knockout (USP5-/-) by CCK8 and colony formation assays. The contents of ferrobivalent ions (Fe2+), reactive oxygen species (ROS), and malondialdehyde (MDA) were detected using a determination kit to observe the relationship between USP5 and ferroptosis. Furthermore, the molecular mechanism study was evaluated by employing Western blotting, co-immunoprecipitation, RT-qPCR, ubiquitination assays, etc. This study showed genetic ablation of USP5 significantly inhibited the viability and proliferation of bladder cancer cells. Genetic ablation of USP5 promoted increases in Fe2+ content, ROS, and MDA levels. The addition of erastin significantly increased the viability and proliferation of T24 USP5-/- cells and significantly increased their ROS and MDA contents. We verified that USP5 deficiency led to a significant reduction in GPX4 protein levels and that the overexpression of USP5 could stabilize the GPX4 protein. Further studies showed that USP5 interacts with GPX4 and stabilizes GPX4 by inhibiting its ubiquitination These findings revealed USP5 inhibits ferroptosis in bladder cancer cells by stabilizing GPX4. The relationship between USP5 and ferroptosis could be a potential therapeutic target for bladder cancer.

The roles of the ubiquitin-proteasome system in renal disease

The ubiquitin-proteasome system (UPS) is a major pathway of specific intracellular protein degradation through proteasome degradation of ubiquitin-labeled substrates. Numerous biological processes, including the cell cycle, transcription, translation, apoptosis, receptor activity, and intracellular signaling, are regulated by UPS. Alterations of the UPS, which render them more or less susceptible to degradation, are responsible for disorders of renal diseases. This review aims to summarize the mechanism of UPS in renal diseases. Besides, this review explores the relationship among UPS, autophagy, and deubiquitination in the development of renal disease. The specific molecular linkages among these systems and pathogenesis, on the other hand, are unknown and controversial. In addition, we briefly describe some anti-renal disease agents targeting UPS components. This review emphasizes UPS as a promising therapeutic modality for the treatment of kidney disease. Our work, though still basic and limited, could provide options to future potential therapeutic targets for renal diseases with a UPS underlying basis.

ATXN3 deubiquitinates ZEB1 and facilitates epithelial-mesenchymal transition in glioblastoma

The activation of epithelial-mesenchymal transition (EMT) promotes glioblastoma (GBM) invasion, thereby enhancing its malignancy. Elucidating the underlying mechanisms that regulate EMT is essential for the development of effective treatments for GBM. In this study, we found that GBM tissues and cells exhibit significantly elevated expression levels of ataxin 3 (ATXN3). Functional experiments demonstrated that ATXN3 promotes the invasion, migration, and tumor growth of GBM cells by activating EMT. Mechanistically, ATXN3 was identified as a bona fide deubiquitinase for ZEB1, a key EMT-inducing transcription factor, in GBM cells. ATXN3 interacts directly with ZEB1, cleaves ubiquitin moieties from conjugated substrates and maintains the stability of ZEB1. Ectopic expression of ZEB1 significantly mitigates the inhibitory effects of ATXN3 depletion on the invasion, migration, and tumor growth of GBM cells. Furthermore, ATXN3 exhibits a positive correlation with ZEB1 expression levels and serves as a predictor of poor prognosis in human GBM specimens. Collectively, our study elucidates a critical ATXN3-ZEB1 signaling axis in EMT and invasion, thereby providing a rationale for potential therapeutic interventions against GBM.

USP39 phase separates into the nucleolus and drives lung adenocarcinoma progression by promoting GLI1 expression

BACKGROUND

Intracellular membraneless organelles formed by liquid-liquid phase separation (LLPS) function in diverse physiological processes and have been linked to tumor-promoting properties. The nucleolus is one of the largest membraneless organelle formed through LLPS. Deubiquitylating enzymes (DUBs) emerge as novel therapeutic targets against human cancers. However, the nucleolar phase separation of DUBs and association with lung cancer development have remained incompletely investigated till now.

METHODS

GFP-USP39 fusion proteins were analyzed for LLPS properties using immunofluorescence, fluorescence recovery after photobleaching (FRAP) and in vitro LLPS assays. Intrinsically-disordered regions of USP39 were analyzed by PhaSepDB database. Transcriptomic profiling, Western blot, RT-PCR and luciferase reporter assays were conducted to identify targets regulated by USP39. The effects of USP39 depletion on tumor progression were tested using doxycycline-inducible USP39 knockdown and rescue lung adenocarcinoma cells both in vitro and in vivo by performing MTT, colony formation, EdU staining, transwell and tumor xenograft model experiments.

RESULTS

USP39 phase separates into nucleoli depending upon its N-terminal disordered region with amino acid residues 1-103. Lung cancer cell growth and migration were dramatically inhibited by USP39 knockdown, which was rescued by exogenous USP39 complementation. Moreover, knockdown of USP39 reduced oncogenic transcription effector GLI1 levels. Finally, USP39 downregulation restricted the formation of lung cancer xenografts in nude mice.

CONCLUSIONS

USP39 undergoes LLPS in the nucleolus and promotes tumor progression by regulating GLI1 expression. Downregulation of USP39 effectively suppressed lung cancer growth, and therefore targeting USP39 provides novel therapeutic strategy to treat lung cancer.

Dysregulation of deubiquitinylases: a linchpin of gastrointestinal diseases

Ubiquitinylation of proteins regulates manifold processes and is reversed by deubiquitinylating enzymes (DUBs), which are therefore implicated in a plethora of cellular processes. DUBs are frequently upregulated in many diseases, while in a few cases downregulation of DUBs is associated with disease progression. This review focuses on the involvement of DUBs in the development and progression of gastrointestinal diseases with a particular emphasis on hepatic steatosis and hepatocellular, cholangio-, esophageal, gastric, colorectal, and pancreatic ductal carcinomas. In addition, pathogens that trigger the activity of several DUBs and thus suppress the immune response and cell survival are discussed. Finally, we highlight recent approaches made towards the therapeutic treatment of gastrointestinal diseases using DUB inhibitors.

USP31 Activates the Wnt/β-catenin Signaling Pathway and Promotes Gastric Cancer Cell Proliferation, Invasion and Migration

BACKGROUND

Gastric cancer (GC) has a poor prognosis because it is highly aggressive, yet there are currently few effective therapies available. Although protein ubiquitination has been shown to play a complex role in the development of gastric cancer, to date, no efficient ubiquitinating enzymes have been identified as treatment targets for GC.

METHODS

The TCGA database was used for bioinformatic investigation of ubiquitin-specific protease 31 (USP31) expression in GC, and experimental techniques, including Western blotting, qRT-PCR, and immunohistochemistry, were used to confirm the findings. We also analyzed the relationship between USP31 expression and clinical prognosis in patients with GC. We further investigated the effects of USP31 on the proliferation, invasion, migration, and glycolysis of GC cells in vitro and in vivo by using colony formation, CCK-8 assays, Transwell chamber assays, cell scratch assays, and cell-derived xenograft. Furthermore, we examined the molecular processes by which USP31 influences the biological development of GC.

RESULTS

Patients with high USP31 expression have a poor prognosis because USP31 is abundantly expressed in GC. Therefore, USP31 reduces the level of ubiquitination of the Wnt/β-catenin pathway by binding to β-catenin, thereby activating glycolysis, which ultimately promotes GC proliferation and aggressive metastasis.

CONCLUSION

USP31 inhibits ubiquitination of β-catenin by binding to it, stimulates the Wnt/β-- catenin pathway, activates glycolysis, and accelerates the biology of GCs, which are all demonstrated in this work.

USP29 alleviates the progression of MASLD by stabilizing ACSL5 through K48 deubiquitination

BACKGROUND/AIMS

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a chronic liver disease characterized by hepatic steatosis. Ubiquitin-specific protease 29 (USP29) plays pivotal roles in hepatic ischemiareperfusion injury and hepatocellular carcinoma, but its role in MASLD remains unexplored. Therefore, the aim of this study was to reveal the effects and underlying mechanisms of USP29 in MASLD progression.

METHODS

USP29 expression was assessed in liver samples from MASLD patients and mice. The role and molecular mechanism of USP29 in MASLD were assessed in high-fat diet-fed and high-fat/high-cholesterol diet-fed mice and palmitic acid and oleic acid treated hepatocytes.

RESULTS

USP29 protein levels were significantly reduced in mice and humans with MASLD. Hepatic steatosis, inflammation and fibrosis were significantly exacerbated by USP29 deletion and relieved by USP29 overexpression. Mechanistically, USP29 significantly activated the expression of genes related to fatty acid β-oxidation (FAO) under metabolic stimulation, directly interacted with long-chain acyl-CoA synthase 5 (ACSL5) and repressed ACSL5 degradation by increasing ACSL5 K48-linked deubiquitination. Moreover, the effect of USP29 on hepatocyte lipid accumulation and MASLD was dependent on ACSL5.

CONCLUSION

USP29 functions as a novel negative regulator of MASLD by stabilizing ACSL5 to promote FAO. The activation of the USP29-ACSL5 axis may represent a potential therapeutic strategy for MASLD.

Targeting and degradation of OTUB1 by Erianin for antimetastasis in esophageal squamous cell carcinoma

BACKGROUND

Metastasis is a major contributor to mortality in patients with esophageal squamous cell carcinoma (ESCC); effective treatment is currently lacking. Erianin, a bioactive ingredient of traditional Chinese medicine, Dendrobium chrysotoxum, has anti-tumor activity against multiple human tumors. However, the effect and associated underlying mechanism of Erianin on ESCC antimetastasis remain unclear.

PURPOSE

To investigate the anti-metastatic properties of Erianin in ESCC both in vitro and in vivo and associated molecular mechanisms.

METHODS

Wound healing assay, Transwell assay, CCK-8 assay, immunohistochemistry, and lung metastasis mouse model were carried out to examine ESCC cell migration and viability in vitro and in vivo. Drug affinity responsive target stability (DARTS), cellular thermal migration assay (CETSA), molecular docking, and Surface plasmon resonance (SPR) assay were used to confirm Erianin binding to ovarian tumor ubiquitin aldehyde-binding protein 1 (OTUB1) protein. Protein stability assay, cell transfection, and western blotting were used to confirm Erianin-mediated degradation of OTUB1 and Snail via the ubiquitin-proteasome pathway. qRT-PCR and western blotting were used to assess OTUB1expression in ESCC tissues.

RESULTS

Erianin suppressed the migration/invasion of ESCC cells without modulating cell viability in vitro and in vivo, bound to OTUB1 through DARTS, CETSA, and molecular docking, and SPR assay, and enhanced OTUB1 degradation via the ubiquitin-proteasome system. Moreover, Erianin inhibited the ESCC epithelial-mesenchymal transition by enhancing the ubiquitination and degradation of Snail via targeting OTUB1.

CONCLUSION

Erianin inhibited ESCC metastasis through ubiquitination and degradation of Snail via targeting OTUB1. Our findings suggest Erianin as a novel OTUB1 inhibitor for preventing ESCC metastasis.

USP5 promotes tumor progression by stabilizing SLUG in bladder cancer

Bladder cancer ranks as the second most prevalent urology malignancy globally. Invasive metastasis is a significant contributor to mortality among patients with bladder cancer, yet the underlying mechanisms remain elusive. Deubiquitinases are pivotal in carcinogenesis, with USP5 implicated in the malignant progression of hepatocellular carcinoma, colorectal cancer and non-small cell lung cancer. The present study assessed the role and mechanism of ubiquitin-specific proteinase 5 (USP5) in the malignant progression of bladder cancer. The association between USP5 expression and bladder cancer prognosis and stage was analyzed using The Cancer Genome Atlas database. Moreover, to elucidate the role of USP5 in bladder cancer, USP5 overexpression and knockdown cell lines were established using T24 cells. Cell viability, proliferation and migration were assessed using Cell Counting Kit-8, Transwell and scratch assays, respectively. Cyclohexanamide was used to evaluate the effect of USP5 expression on Snail family zinc finger 2 (SLUG) stability. Immunoprecipitation and immunofluorescence co-localization were utilized to probe the interaction between USP5 and SLUG. Changes in mRNA and protein levels were assessed using reverse transcription-quantitative PCR and western blotting, respectively. The results revealed that patients with bladder cancer with high USP5 expression had significantly shorter survival (P<0.05) and a higher clinicopathologic stage (P<0.05) than those with low USP5 expression. T24 cells overexpressing USP5 demonstrated significantly increased proliferation (P<0.05), invasion (P<0.05) and expression of epithelial-mesenchymal transition markers (P<0.05); whereas T24 cells with knocked-down USP5 expression revealed significantly reduced proliferation (P<0.05), invasion (P<0.05) and epithelial-mesenchymal transition markers (P<0.05). Immunoprecipitation experiments demonstrated the binding of USP5 to SLUG in bladder cancer cells, with further analysis revealing that USP5 upregulated protein levels of SLUG by inhibiting its ubiquitination. Furthermore, the treatment of bladder cancer cells with Degrasyn, a USP5 inhibitor, was associated with a significant inhibition of the proliferation (P<0.05) and invasion (P<0.05) of T24 cells. In conclusion, the findings of the present study underscore the role of USP5 in promoting the malignant progression of bladder cancer through the stabilization of SLUG. Targeting USP5 holds promise as a strategy for inhibiting bladder cancer progression.

Deubiquitinases as novel therapeutic targets for diseases

Deubiquitinating enzymes (DUBs) regulate substrate ubiquitination by removing ubiquitin or cleaving within ubiquitin chains, thereby maintaining cellular homeostasis. Approximately 100 DUBs in humans counteract E3 ubiquitin ligases, finely balancing ubiquitination and deubiquitination processes to maintain cellular proteostasis and respond to various stimuli and stresses. Given their role in modulating ubiquitination levels of various substrates, DUBs are increasingly linked to human health and disease. Here, we review the DUB family, highlighting their distinctive structural characteristics and chain-type specificities. We show that DUB family members regulate key signaling pathways, such as NF-κB, PI3K/Akt/mTOR, and MAPK, and play crucial roles in tumorigenesis and other diseases (neurodegenerative disorders, cardiovascular diseases, inflammatory disorders, and developmental diseases), making them promising therapeutic targets Our review also discusses the challenges in developing DUB inhibitors and underscores the critical role of the DUBs in cellular signaling and cancer. This comprehensive analysis enhances our understanding of the complex biological functions of the DUBs and underscores their therapeutic potential.

Acquired Bortezomib Resistance in Multiple Myeloma: From Mechanisms to Strategy

OPINION STATEMENT

Multiple myeloma (MM) is a heterogeneous plasma cell tumor with a survival period of several months to over ten years. Despite the development of various new drugs, MM is still incurable and recurs repeatedly. Bortezomib, a landmark event in the history of MM treatment, has dramatically improved the prognosis of patients with MM. Although proteasome inhibitors (PIs) represented by bortezomib, have greatly prolonged MM survival, unfortunately, almost all MM will develop bortezomib resistance, leading to relapse with a shorter survival. It has been reported that both the tumor microenvironment and myeloma cells drive bortezomib resistance. Multiple treatment methods have been attempted to overcome bortezomib resistance, but unfortunately, there has been no breakthrough. It is believed that the key resistance mechanism has not yet been discovered. A deeper understanding of the mechanism of bortezomib resistance and strategies to overcome it can help identify key resistance mechanisms and further improve the prognosis of MM.

CaMKII Exacerbates Doxorubicin-Induced Cardiotoxicity by Promoting Ubiquitination Through USP10 Inhibition

BACKGROUND

Doxorubicin (DOX) is an effective anticancer drug, but it has a problem of cardiotoxicity that cannot be ignored. Ca2+/calmodulin-dependent protein kinase II (CaMKII) is tightly associated with the pathological progression of DOX-induced cardiotoxicity. Ubiquitin-specific protease 10 (USP10) plays an important role in many biological processes and cancers. However, its association with DOX-induced cardiotoxicity and CaMKII remains unclear.

METHODS

H9C2 cells, HL-1 cells and C57BL/6 mice were used to establish the DOX-induced cardiotoxicity model, and the CaMKII-specific inhibitor KN-93 and USP10 specific inhibitor Spautin-1 were used to observe the CaMKII and USP10 effect. In cell experiments, CCK-8 method was used to assess cell viability, LDH kit was used to assess lactate dehydrogenase expression, DCFH-DA staining was used to observe changes in active oxygen content, TUNEL staining was used to observe cell apoptosis, and Western blotting method was used to detect relevant protein markers. The expression of p-CaMKII and USP10 was assessed by immunofluorescence staining. In animal experiments, mouse echocardiograph was used were used to evaluate cardiac function, and HE staining and Masson staining were used to evaluate myocardial injury. Cardiomyocyte apoptosis was detected by TUNEL staining. Western blotting method was used to detect relevant protein markers.

RESULTS

Our results demonstrated that activation of CaMKII and inhibition of USP10 pathway related to DOX-induced cardiotoxicity. Inhibition of CaMKII with KN-93 ameliorated DOX-induced cardiac dysfunction and cytotoxicity. In addition, CaMKII inhibition prevented DOX-induced apoptosis and ubiquitination. Furthermore, CaMKII inhibition increased USP10 expression in DOX-treated mouse hearts, H9C2 cells and HL-1 cells. At last, the USP10 inhibitor, Spautin-1, blocked the regulatory effect of CaMKII inhibition on apoptosis and ubiquitination in DOX-induced cardiotoxicity.

CONCLUSION

Our findings revealed that DOX-induced myocardial apoptosis and activated CaMKII through cellular and animal levels, while providing a novel probe into the mechanism of CaMKII action: promoting ubiquitination by inhibiting USP10 aggravated apoptosis.

USP33 facilitates the ovarian cancer progression via deubiquitinating and stabilizing CBX2

Post-translational modifications of proteins play a pivotal role in both the initiation and progression of ovarian cancer. Despite the recognition of USP33 as a significant factor in various cancers, its specific function and underlying mechanisms in ovarian cancer remain elusive. Proteomics and ubiquitinomics approaches were coupled to screen novel substrate proteins directly regulated by USP33. Our findings unveil that USP33 was observed to eliminate K27- and K48-linked ubiquitin chains from CBX2 at the K277 position. Notably, acetylation of CBX2 at K199, catalyzed by lysine acetyltransferase GCN5, was found to enhance its interaction with USP33, subsequently promoting further deubiquitination and stabilization. Functionally, our experiments demonstrate that USP33 significantly enhances ovarian cancer proliferation and metastasis in a CBX2-dependent manner. Furthermore, analysis revealed a direct positive correlation between the expression levels of USP33 and CBX2 proteins in human specimens, with elevated levels being associated with reduced survival rates in ovarian cancer patients. These findings elucidate the mechanism by which USP33 augments ovarian cancer progression through the stabilization of CBX2, underscoring the USP33-CBX2 axis as a promising therapeutic target in ovarian cancer management.

The role of ubiquitination in health and disease

Ubiquitination is an enzymatic process characterized by the covalent attachment of ubiquitin to target proteins, thereby modulating their degradation, transportation, and signal transduction. By precisely regulating protein quality and quantity, ubiquitination is essential for maintaining protein homeostasis, DNA repair, cell cycle regulation, and immune responses. Nevertheless, the diversity of ubiquitin enzymes and their extensive involvement in numerous biological processes contribute to the complexity and variety of diseases resulting from their dysregulation. The ubiquitination process relies on a sophisticated enzymatic system, ubiquitin domains, and ubiquitin receptors, which collectively impart versatility to the ubiquitination pathway. The widespread presence of ubiquitin highlights its potential to induce pathological conditions. Ubiquitinated proteins are predominantly degraded through the proteasomal system, which also plays a key role in regulating protein localization and transport, as well as involvement in inflammatory pathways. This review systematically delineates the roles of ubiquitination in maintaining protein homeostasis, DNA repair, genomic stability, cell cycle regulation, cellular proliferation, and immune and inflammatory responses. Furthermore, the mechanisms by which ubiquitination is implicated in various pathologies, alongside current modulators of ubiquitination are discussed. Enhancing our comprehension of ubiquitination aims to provide novel insights into diseases involving ubiquitination and to propose innovative therapeutic strategies for clinical conditions.

The ubiquitin-proteasome system in the tumor immune microenvironment: a key force in combination therapy

The ubiquitin-proteasome system (UPS) plays a crucial role in modulating the proliferation, activation, and normal functioning of immune cells through the regulation of protein degradation and function. By influencing the expression of immune checkpoint-associated proteins, the UPS modulates T cell-mediated anti-tumor immune responses and can potentially facilitate the immune escape of tumor cells. Additionally, the UPS contributes to the remodeling of the tumor immunosuppressive microenvironment (TIME) by regulating B cells, dendritic cells (DCs), macrophages, and Treg cells. Targeting the UPS in conjunction with immune checkpoint-associated proteins, and combining these with other therapeutic approaches, may significantly enhance the efficacy of combination therapies and pave the way for novel cancer treatment strategies. In this review, we first summarize the composition and alterations of the TIME, with a particular emphasis on the role of the UPS in TIME and its interactions with various immune cell types. Finally, we explore the potential of combining UPS-targeted therapies with immunotherapy to substantially improve the effectiveness of immunotherapy and enhance patient survival outcomes.

Ubiquitin specific peptidase 3: an emerging deubiquitinase that regulates physiology and diseases

Proteins are the keystone for the execution of various life activities, and the maintenance of protein normalization is crucial for organisms. Ubiquitination, as a post-transcriptional modification, is widely present in organisms, and it relies on the sophisticated ubiquitin-proteasome (UPS) system that controls protein quality and modulates protein lifespan. Deubiquitinases (DUBs) counteract ubiquitination and are essential for the maintenance of homeostasis. Ubiquitin specific peptidase 3 (USP3) is a member of the DUBs that has received increasing attention in recent years. USP3 is a novel chromatin modifier that tightly regulates the DNA damage response (DDR) and maintains genome integrity. Meanwhile, USP3 acts as a key regulator of inflammatory vesicles and sustains the normal operation of the innate immune system. In addition, USP3 is aberrantly expressed in a wide range of cancers, such as gastric cancer, glioblastoma and neuroblastoma, implicating that USP3 could be an effective target for targeted therapies. In this review, we retrace all the current researches of USP3, describe the structure of USP3, elucidate its functions in DNA damage, immune and inflammatory responses and the cell cycle, and summarize the important role of USP3 in multiple cancers and diseases.

Unraveling role of ubiquitination in drug resistance of gynecological cancer

Chemotherapy is the principal treatment for advanced cancer patients. However, chemotherapeutic resistance, an important hallmark of cancer, is considered as a key impediment to effective therapy in cancer patients. Multiple signaling pathways and factors have been underscored to participate in governing drug resistance. Posttranslational modifications, including ubiquitination, glycosylation, acetylation and phosphorylation, have emerged as key players in modulating drug resistance in gynecological tumors, such as ovarian cancer, cervical cancer and endometrial cancer. In this review article, we summarize the role of ubiquitination in governing drug sensitivity in gynecological cancers. Moreover, we describe the numerous compounds that target ubiquitination in gynecological cancers to reverse chemotherapeutic resistance. In addition, we provide the future perspectives to fully elucidate the mechanisms by which ubiquitination controls drug resistance in gynecological tumors, contributing to restoring drug sensitivity. This review highlights the complex interplay between ubiquitination and drug resistance in gynecological tumors, providing novel insights into potential therapeutic targets and personalized treatment strategies to overcome the bottleneck of drug resistance.

Ubiquitous regulation of cerebrovascular diseases by ubiquitin-modifying enzymes

Cerebrovascular diseases (CVDs) are a major threat to global health. Elucidation of the molecular mechanisms underlying the pathology of CVDs is critical for the development of efficacious preventative and therapeutic approaches. Accumulating studies have highlighted the significance of ubiquitin-modifying enzymes (UMEs) in the regulation of CVDs. UMEs are a group of enzymes that orchestrate ubiquitination, a post-translational modification tightly involved in CVDs. Functionally, UMEs regulate multiple pathological processes in ischemic and hemorrhagic stroke, moyamoya disease, and atherosclerosis. Considering the important roles of UMEs in CVDs, they may become novel druggable targets for these diseases. Besides, techniques applying UMEs, such as proteolysis-targeting chimera and deubiquitinase-targeting chimera, may also revolutionize the therapy of CVDs in the future.

PTMs of PD-1/PD-L1 and PROTACs application for improving cancer immunotherapy

Immunotherapy has been developed, which harnesses and enhances the innate powers of the immune system to fight disease, particularly cancer. PD-1 (programmed death-1) and PD-L1 (programmed death ligand-1) are key components in the regulation of the immune system, particularly in the context of cancer immunotherapy. PD-1 and PD-L1 are regulated by PTMs, including phosphorylation, ubiquitination, deubiquitination, acetylation, palmitoylation and glycosylation. PROTACs (Proteolysis Targeting Chimeras) are a type of new drug design technology. They are specifically engineered molecules that target specific proteins within a cell for degradation. PROTACs have been designed and demonstrated their inhibitory activity against the PD-1/PD-L1 pathway, and showed their ability to degrade PD-1/PD-L1 proteins. In this review, we describe how PROTACs target PD-1 and PD-L1 proteins to improve the efficacy of immunotherapy. PROTACs could be a novel strategy to combine with radiotherapy, chemotherapy and immunotherapy for cancer patients.