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Biochemical Society Transactions Jun 2024In vivo, muscle and neuronal cells are post-mitotic, and their function is predominantly regulated by proteostasis, a multilayer molecular process that maintains a... (Review)
Review
In vivo, muscle and neuronal cells are post-mitotic, and their function is predominantly regulated by proteostasis, a multilayer molecular process that maintains a delicate balance of protein homeostasis. The ubiquitin-proteasome system (UPS) is a key regulator of proteostasis. A dysfunctional UPS is a hallmark of muscle ageing and is often impacted in neuromuscular disorders (NMDs). Malfunction of the UPS often results in aberrant protein accumulation which can lead to protein aggregation and/or mis-localization affecting its function. Deubiquitinating enzymes (DUBs) are key players in the UPS, controlling protein turnover and maintaining the free ubiquitin pool. Several mutations in DUB encoding genes are linked to human NMDs, such as ATXN3, OTUD7A, UCHL1 and USP14, whilst other NMDs are associated with dysregulation of DUB expression. USP5, USP9X and USP14 are implicated in synaptic transmission and remodeling at the neuromuscular junction. Mice lacking USP19 show increased maintenance of lean muscle mass. In this review, we highlight the involvement of DUBs in muscle physiology and NMDs, particularly in processes affecting muscle regeneration, degeneration and inflammation following muscle injury. DUBs have recently garnered much respect as promising drug targets, and their roles in muscle maturation, regeneration and degeneration may provide the framework for novel therapeutics to treat muscular disorders including NMDs, sarcopenia and cachexia.
Topics: Humans; Animals; Deubiquitinating Enzymes; Muscle, Skeletal; Proteasome Endopeptidase Complex; Ubiquitin; Neuromuscular Diseases; Muscular Diseases; Mice; Proteostasis
PubMed: 38716888
DOI: 10.1042/BST20230562 -
Biomedicines Dec 2023Radiotherapy, a treatment method employing radiation to eradicate tumor cells and subsequently reduce or eliminate tumor masses, is widely applied in the management of... (Review)
Review
Radiotherapy, a treatment method employing radiation to eradicate tumor cells and subsequently reduce or eliminate tumor masses, is widely applied in the management of numerous patients with tumors. However, its therapeutic effectiveness is somewhat constrained by various drug-resistant factors. Recent studies have highlighted the ubiquitination/deubiquitination system, a reversible molecular modification pathway, for its dual role in influencing tumor behaviors. It can either promote or inhibit tumor progression, impacting tumor proliferation, migration, invasion, and associated therapeutic resistance. Consequently, delving into the potential mechanisms through which ubiquitination and deubiquitination systems modulate the response to radiotherapy in malignant tumors holds paramount significance in augmenting its efficacy. In this paper, we comprehensively examine the strides made in research and the pertinent mechanisms of ubiquitination and deubiquitination systems in governing radiotherapy resistance in tumors. This underscores the potential for developing diverse radiosensitizers targeting distinct mechanisms, with the aim of enhancing the effectiveness of radiotherapy.
PubMed: 38137461
DOI: 10.3390/biomedicines11123240 -
Cancer Letters Feb 2024Smad3 is the key mediator of TGF-β1-triggered signal transduction and the related biological responses, promoting cell invasion and metastasis in various cancers,...
Smad3 is the key mediator of TGF-β1-triggered signal transduction and the related biological responses, promoting cell invasion and metastasis in various cancers, including lung cancer. However, the deubiquitinase stabilizing Smad3 remains unknown. In this study, we present a paradigm in which POH1 is identified as a novel deubiquitinase of Smad3 that plays a tumor-promoting role in lung adenocarcinoma (LUAD) by regulating Smad3 stability. POH1 markedly increased Smad3 protein levels and prolonged its half-life. POH1 directly interacted and colocalized with Smad3, leading to the removal of poly-deubiquitination of Smad3. Functionally, POH1 facilitated cell proliferation, migration, and invasion by stabilizing Smad3. Importantly, POH1 also promoted liver metastasis of lung cancer cells. The protein levels of both POH1 and Smad3 were raised in the tumor tissues of patients with LUAD, which predicts poor prognosis. Collectively, we demonstrate that POH1 acts as an oncoprotein by enhancing TGF-β1/Smad3 signaling and TGF-β1-mediated metastasis of lung cancer.
Topics: Humans; Lung Neoplasms; Transforming Growth Factor beta1; Smad3 Protein; Cell Line, Tumor; Adenocarcinoma of Lung; Deubiquitinating Enzymes; Cell Movement
PubMed: 38061486
DOI: 10.1016/j.canlet.2023.216526 -
Metabolism: Clinical and Experimental Aug 2023Na/K-ATPase (NKA), an ion pumping enzyme ubiquitously expressed in various cells, is critically involved in cellular ion homeostasis and signal transduction. However,...
BACKGROUND
Na/K-ATPase (NKA), an ion pumping enzyme ubiquitously expressed in various cells, is critically involved in cellular ion homeostasis and signal transduction. However, the role of NKA in hepatic lipid homeostasis has yet to be fully characterized.
METHODS
The activity of NKA and NKAα1 expression were determined in steatotic cells, mice and patients. The roles of NKAα1 in hepatosteatosis were detected using hepatocyte knockout or specific overexpression of NKAα1 in mice.
RESULTS
Herein, we demonstrated that the expression and activity of α1 subunit of NKA (NKAα1) were lowered in the livers of nonalcoholic fatty liver disease (NAFLD) patients, high-fat diet (HFD)-induced obese mice, and genetically obese (ob/ob, db/db) mice, as well as oleic acid-induced hepatocytes. Hepatic deficiency of NKAα1 exacerbated, while adeno-associated virus-mediated liver specific overexpression of NKAα1 alleviated hepatic steatosis through regulation of fatty acid oxidation (FAO) and lipogenesis. Mechanistically, we revealed that NKAα1 upregulated sirtuin 1 (SIRT1) via interacting with ubiquitin specific peptidase 22 (USP22), a deubiquitinating enzyme for the stabilization and deubiquitination of SIRT1, thus activating the downstream autophagy signaling. Blockade of the SIRT1/autophagy signaling pathway eliminated the protective effects of NKAα1 against lipid deposition in hepatocytes. Importantly, we found that an antibody against the DR region (DVEDSYGQQWTYEQR) of NKAα1 subunit (DR-Ab) ameliorated hepatic steatosis through maintaining the membrane density of NKAα1 and inducing its activation.
CONCLUSIONS
Collectively, this study renews the functions of NKAα1 in liver lipid metabolism and provides a new clue for gene therapy or antibody treatment of hepatic lipid metabolism disturbance by targeting NKAα1.
Topics: Mice; Animals; Mice, Obese; Lipid Metabolism; Sirtuin 1; Liver; Non-alcoholic Fatty Liver Disease; Hepatocytes; Oleic Acid; Diet, High-Fat; Mice, Inbred C57BL
PubMed: 37127227
DOI: 10.1016/j.metabol.2023.155579 -
Science Bulletin Jun 2024Molecular glues are typically small chemical molecules that act at the interface between a target protein and degradation machinery to trigger ternary complex formation....
Molecular glues are typically small chemical molecules that act at the interface between a target protein and degradation machinery to trigger ternary complex formation. Identifying molecular glues is challenging. There is a scarcity of target-specific upregulating molecular glues, which are highly anticipated for numerous targets, including P53. P53 is degraded in proteasomes through polyubiquitination by specific E3 ligases, whereas deubiquitinases (DUBs) remove polyubiquitination conjugates to counteract these E3 ligases. Thus, small-molecular glues that enhance P53 anchoring to DUBs may stabilize P53 through deubiquitination. Here, using small-molecule microarray-based technology and unbiased screening, we identified three potential molecular glues that may tether P53 to the DUB, USP7, and elevate the P53 level. Among the molecular glues, bromocriptine (BC) is an FDA-approved drug with the most robust effects. BC was further verified to increase P53 stability via the predicted molecular glue mechanism engaging USP7. Consistent with P53 upregulation in cancer cells, BC was shown to inhibit the proliferation of cancer cells in vitro and suppress tumor growth in a xenograft model. In summary, we established a potential screening platform and identified potential molecular glues upregulating P53. Similar strategies could be applied to the identification of other types of molecular glues that may benefit drug discovery and chemical biology studies.
Topics: Ubiquitin-Specific Peptidase 7; Tumor Suppressor Protein p53; Humans; Animals; Up-Regulation; Mice; Cell Line, Tumor; Ubiquitination; Cell Proliferation; Xenograft Model Antitumor Assays; Mice, Nude
PubMed: 38734583
DOI: 10.1016/j.scib.2024.04.017 -
Cancer Cell International Sep 2023Myosin heavy chain 9 (MYH9) plays an important role in a number of diseases. Nevertheless, the function of MYH9 in glioma is unclear. The present research aimed to...
Myosin heavy chain 9 (MYH9) plays an important role in a number of diseases. Nevertheless, the function of MYH9 in glioma is unclear. The present research aimed to investigate the role of MYH9 in glioma and determine whether MYH9 is involved in the temozolomide chemoresistance of glioma cells. Our results showed that MYH9 increased the proliferation and temozolomide resistance of glioma cells. The mechanistic experiments showed that the binding of MYH9 to NAP1L1, a potential promoter of tumor proliferation, inhibited the ubiquitination and degradation of NAP1L1 by recruiting USP14. Upregulation of NAP1L1 increased its binding with c-Myc and activated c-Myc, which induced the expression of CCND1/CDK4, promoting glioma cell temozolomide resistance and proliferation. Additionally, we found that MYH9 upregulation was strongly related to patient survival and is therefore a negative factor for patients with glioma. Altogether, our results show that MYH9 plays a role in glioma progression by regulating NAP1L1 deubiquitination. Thus, targeting MYH9 is a potential therapeutic strategy for the clinical treatment of glioma in the future.
PubMed: 37770914
DOI: 10.1186/s12935-023-03050-1 -
Cell Discovery Nov 2023
PubMed: 37923714
DOI: 10.1038/s41421-023-00618-z -
Molecular Cancer Apr 2024CDC6 is an oncogenic protein whose expression level fluctuates during the cell cycle. Although several E3 ubiquitin ligases responsible for the ubiquitin-mediated...
BACKGROUND
CDC6 is an oncogenic protein whose expression level fluctuates during the cell cycle. Although several E3 ubiquitin ligases responsible for the ubiquitin-mediated proteolysis of CDC6 have been identified, the deubiquitination pathway for CDC6 has not been investigated.
METHODS
The proteome-wide deubiquitinase (DUB) screening was used to identify the potential regulator of CDC6. Immunofluorescence, protein half-life and deubiquitination assays were performed to determine the protein stability of CDC6. Gain- and loss-of-function experiments were implemented to analyse the impacts of OUTD6A-CDC6 axis on tumour growth and chemosensitivity in vitro. N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)-induced conditional Otud6a knockout (CKO) mouse model and tumour xenograft model were performed to analyse the role of OTUD6A-CDC6 axis in vivo. Tissue specimens were used to determine the association between OTUD6A and CDC6.
RESULTS
OTUD6A interacts with, depolyubiquitinates and stabilizes CDC6 by removing K6-, K33-, and K48-linked polyubiquitination. Moreover, OTUD6A promotes cell proliferation and decreases sensitivity to chemotherapy by upregulating CDC6. CKO mice are less prone to BCa tumorigenesis induced by BBN, and knockdown of OTUD6A inhibits tumour progression in vivo. Furthermore, OTUD6A protein level has a positive correlation with CDC6 protein level, and high protein levels of OTUD6A and CDC6 are associated with poor prognosis in patients with bladder cancer.
CONCLUSIONS
We reveal an important yet missing piece of novel DUB governing CDC6 stability. In addition, our findings propose a model for the OTUD6A-CDC6 axis that provides novel insights into cell cycle and chemosensitivity regulation, which may become a potential biomarker and promising drug target for cancer treatment.
Topics: Animals; Humans; Ubiquitination; Mice; Drug Resistance, Neoplasm; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Disease Progression; Mice, Knockout; Xenograft Model Antitumor Assays; Gene Expression Regulation, Neoplastic; Deubiquitinating Enzymes; Disease Models, Animal; Nuclear Proteins
PubMed: 38685067
DOI: 10.1186/s12943-024-01996-y -
Journal of Experimental & Clinical... Jan 2024Glioblastoma (GBM) is the most common malignant tumor of the central nervous system. It is an aggressive tumor characterized by rapid proliferation, diffuse tumor...
BACKGROUND
Glioblastoma (GBM) is the most common malignant tumor of the central nervous system. It is an aggressive tumor characterized by rapid proliferation, diffuse tumor morphology, and poor prognosis. Unfortunately, current treatments, such as surgery, radiotherapy, and chemotherapy, are unable to achieve good outcomes. Therefore, there is an urgent need to explore new treatment targets. A detailed mechanistic exploration of the role of the nuclear pore transporter KPNB1 in GBM is lacking. This study demonstrated that KPNB1 regulated GBM progression through a transcription factor YBX1 to promote the expression of post-protrusion membrane protein NLGN3. This regulation was mediated by the deubiquitinating enzyme USP7.
METHODS
A tissue microarray was used to measure the expression of KPNB1 and USP7 in glioma tissues. The effects of KPNB1 knockdown on the tumorigenic properties of glioma cells were characterized by colony formation assays, Transwell migration assay, EdU proliferation assays, CCK-8 viability assays, and apoptosis analysis using flow cytometry. Transcriptome sequencing identified NLGN3 as a downstream molecule that is regulated by KPNB1. Mass spectrometry and immunoprecipitation were performed to analyze the potential interaction between KPNB1 and YBX1. Moreover, the nuclear translocation of YBX1 was determined with nuclear-cytoplasmic fractionation and immunofluorescence staining, and chromatin immunoprecipitation assays were conducted to study DNA binding with YBX1. Ubiquitination assays were performed to determine the effects of USP7 on KPNB1 stability. The intracranial orthotopic tumor model was used to detect the efficacy in vivo.
RESULTS
In this study, we found that the nuclear receptor KPNB1 was highly expressed in GBM and could mediate the nuclear translocation of macromolecules to promote GBM progression. Knockdown of KPNB1 inhibited the progression of GBM, both in vitro and in vivo. In addition, we found that KPNB1 could regulate the downstream expression of Neuroligin-3 (NLGN3) by mediating the nuclear import of transcription factor YBX1, which could bind to the NLGN3 promoter. NLGN3 was necessary and sufficient to promote glioma cell growth. Furthermore, we found that deubiquitinase USP7 played a critical role in stabilizing KPNB1 through deubiquitination. Knockdown of USP7 expression or inhibition of its activity could effectively impair GBM progression. In vivo experiments also demonstrated the promoting effects of USP7, KPNB1, and NLGN3 on GBM progression. Overall, our results suggested that KPNB1 stability was enhanced by USP7-mediated deubiquitination, and the overexpression of KPNB1 could promote GBM progression via the nuclear translocation of YBX1 and the subsequent increase in NLGN3 expression.
CONCLUSION
This study identified a novel and targetable USP7/KPNB1/YBX1/NLGN3 signaling axis in GBM cells.
Topics: Humans; Apoptosis; beta Karyopherins; Brain Neoplasms; Glioblastoma; Glioma; Transcription Factors; Ubiquitin-Specific Peptidase 7; Y-Box-Binding Protein 1
PubMed: 38254206
DOI: 10.1186/s13046-024-02954-8 -
Journal of Translational Medicine Jul 2023USP51 is a deubiquitinase (DUB), that is involved in diverse cellular processes. Accumulating evidence has demonstrated that USP51 contributes to cancer development....
BACKGROUND
USP51 is a deubiquitinase (DUB), that is involved in diverse cellular processes. Accumulating evidence has demonstrated that USP51 contributes to cancer development. However, its impact on non-small cell lung carcinoma (NSCLC) cell malignancy is largely unknown.
METHODS
In this study, we performed bioinformatics analysis on a dataset from The Cancer Genome Atlas to determine the association between USP51 and cell stemness marker expression in NSCLC patients. RT‒qPCR, Western blotting, and flow cytometry were performed to examine the effects of USP51 depletion on stemness marker expression. Colony formation and tumor sphere formation assays were used to assess the stemness of NSCLC cells. A cycloheximide chase time-course assay and a polyubiquitination assay were carried out to analyze the effects of USP51 on the TWIST1 protein level. TWIST1 was overexpressed in USP51 knockdown NSCLC cells to determine whether TWIST1 is required. The effect of USP51 on the in vivo growth of NSCLC cells was tested through subcutaneous injections in mice.
RESULTS
We found that USP51 deubiquitinates TWIST1, which is significantly upregulated in the tissues of patients with NSCLC and is closely associated with poor prognosis. USP51 expression was positively correlated with the expression of stemness marker CD44, SOX2, NANOG, and OCT4 in NSCLC patients. USP51 depletion attenuated mRNA, protein, and cell surface expression of stemness markers and the stemness of NSCLC cells. Ectopic USP51 expression potentiated the stability of the TWIST1 protein by attenuating its polyubiquitination. In addition, TWIST1 re-expression in NSCLC cells reversed the inhibitory effect of USP51 knockdown on cell stemness. Furthermore, the in vivo results confirmed the suppressive effect of USP51 depletion on NSCLC cell growth.
CONCLUSIONS
Our results show that USP51 maintains the stemness of NSCLC cells by deubiquitinating TWIST1. Knocking it down reduces both cell stemness and growth of NSCLC cells.
Topics: Animals; Mice; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; Lung Neoplasms; Twist-Related Protein 1; Humans; Ubiquitin-Specific Proteases
PubMed: 37422632
DOI: 10.1186/s12967-023-04304-2