BACKGROUND: Epigenetics has been shown to be relevant in oncology: BMI1 overexpression has been reported in leukemias, EZH2 mutations have been found in follicular lymphoma, and USP22 seems to stabilize BMI1 protein. In this study, we measured the expression of BMI1, EZH2, and USP22 in lymph nodes from 56 diffuse large B-cell lymphoma (DLBCL) patients.
METHODS: A new multiplex digital droplet PCR (ddPCR) has been set up to measure the expression of 4 genes (BMI1, EZH2, USP22, and GAPDH) in the same reaction on RNA extracted from paraffin-embedded tissues.
RESULTS: The specificity of ddPCR was confirmed by a 100% alignment on the BLAST platform and its repeatability demonstrated by duplicates. A strict correlation between expression of BMI1 and EZH2 and BMI1 and USP22 has been found, and high expression of these genes was correlated with extra-nodal lymphomas. Progression-free survival (PFS) and overall survival (OS) were conditioned by IPI, bone marrow infiltration, and the complete response achievement. High levels of BMI1 and USP22 did not condition the response to therapy, but impaired the PFS, especially for patients defined at \"high risk\" based on the cell of origin (no germinal center [GCB]), high BCL2 expression, and IPI 3-5. In this subgroup, the probability of relapse/progression was twice higher than that of patients carrying low BMI1 and USP22 levels.
CONCLUSIONS: High expression of BMI1 and of USP22 might be a poor prognostic factor in DLBCL, and might represent the target for novel inhibitors.

BACKGROUND: Lung adenocarcinoma (LUAD) is a highly aggressive and rapidly fatal malignancy worldwide. Collagen XVII (COL17A1) has been implicated in various protumorigenic processes. However, the functions and mechanisms of COL17A1 in LUAD progression still remain elusive.
METHODS: COL17A1 and ubiquitin-specific protease 22 (USP22) mRNA analysis was performed by quantitative PCR, and their protein levels were detected by immunoblotting and immunohistochemistry. The functional influence was evaluated by determining cell viability, proliferation, apoptosis, invasion, migration, and ferroptosis in vitro, as well as xenograft growth in vivo. Co-immunoprecipitation (Co-IP) and IP experiments were used to examine the USP22/COL17A1 interaction and COL17A1 deubiquitination. Cycloheximide treatment was used to analyze COL17A1 protein stability.
RESULTS: COL17A1 and USP22 were upregulated in human LUAD tissues and cell lines. Functionally, COL17A1 knockdown acted for the suppression of LUAD cell growth, invasion, and migration as well as promotion of cell apoptosis and ferroptosis in vitro. COL17A1 knockdown could diminish the tumorigenicity of LUAD cells in vivo. Mechanistically, USP22 stabilized and upregulated COL17A1 by enhancing the deubiquitination of COL17A1. Additionally, reexpression of COL17A1 could reverse USP22 silencing-induced phenotype changes of LUAD cells in vitro.
CONCLUSIONS: Our findings demonstrate that USP22-stabilized COL17A1 possesses oncogenic activity in LUAD. We propose that USP22 and COL17A1 would be potential targets for the establishment of therapeutic approaches against LUAD.

Metastasis is a major contributing factor that affects the prognosis of melanoma patients. Nevertheless, the underlying molecular mechanisms involved in melanoma metastasis are not yet entirely understood. Here, we identified ubiquitin-specific protease 22 (USP22) as a pro-oncogenic protein in melanoma through screening the survival profiles of 52 ubiquitin-specific proteases (USPs). USP22 demonstrates a strong association with poor clinical outcomes and is significantly overexpressed in melanoma. Ablation of USP22 expression remarkably attenuates melanoma migration, invasion, and epithelial-mesenchymal transition in vitro and suppresses melanoma metastasis in vivo. Mechanistically, USP22 controls melanoma metastasis through the SIRT1/PTEN/PI3K pathway. In addition, we conducted an United States Food and Drug Administration-approved drug library screening and identified topotecan as a clinically applicable USP22-targeting molecule by promoting proteasomal degradation of USP22. Finally, we found that both pharmacological and genetic silence of USP22 sensitize RSL3-induced ferroptosis through suppressing the PI3K/Akt/mTOR pathway and its downstream SCD, and ferroptosis inhibitor could partly rescued the decreased lung metastasis by topotecan in vivo. Overall, our findings reveal a prometastatic role of USP22 and identify topotecan as a potent USP22-targeting drug to limit melanoma metastasis.

Endometritis and the failure of decidualization of the endometrium are important factors contributing to the increased incidence of abortion. USP22 is associated with various inflammatory diseases and has been shown to be involved in endometrial decidualization in mice. This study aims to investigate whether USP22 is involved in the regulation of inflammatory response and decidualization in human endometrial stromal cells (hESCs). In this study, lipopolysaccharide (LPS) was used to induce inflammation in hESCs, and MPA combined with cAMP was used to induce decidualization of hESCs. USP22 overexpression vector was constructed to study the role of USP22 in endometritis. The results showed that the USP22 protein and mRNA levels were decreased in LPS-induced hESCs. LPS induction increased the levels of TNF-α, IL-1β, and IL-6, as well as the expression of iNOS and COX2 proteins in hESCs. In the LPS group, the levels of F-actin, PRL, IGFBP1, SLC7A11, and GPX4 proteins decreased, while the levels of lipid peroxidation and total iron content increased. Additionally, the levels of ACSL4 and TFR1 proteins were up-regulated. Overexpression of USP22 reversed LPS-induced cellular inflammation, attenuated decidualization, and inhibited ferroptosis. However, the use of ferroptosis inducers diminished the regulatory effects of USP22 on inflammatory responses and decidualization. In summary, these suggested that USP22 reduces the LPS-induced inflammatory response and regulates the decidualization of hESCs, and possibly involving ferroptosis.

Hypoxic preconditioning has been recognized as a promotive factor for accelerating cutaneous wound healing. Our previous study uncovered that exosomal lncRNA H19, derived from adipose-derived stem cells (ADSCs), plays a crucial role in orchestrating cutaneous wound healing. Herein, we aimed to explore whether there is a connection between hypoxia and ADSC-derived exosomes (ADSCs-exos) in cutaneous wound healing. Exosomes extracted from ADSCs under normoxic and hypoxic conditions were identified using transmission electron microscope (TEM) and particle size analysis. The effects of ADSCs-exos on the proliferation, migration, and angiogenesis of human umbilical vein endothelial cells (HUVECs) were evaluated by CCK-8, EdU, wound healing, and tube formation assays. Expression patterns of H19, HIF-1α, and USP22 were measured. Co-immunoprecipitation, chromatin immunoprecipitation, ubiquitination, and luciferase reporter assays were conducted to confirm the USP22/HIF-1α/H19 axis, which was further validated in a mice model of skin wound. Exosomes extracted from hypoxia-treated ADSCs (termed as H-ADSCs-exos) significantly increased cell proliferation, migration, and angiogenesis in H2O2-exposed HUVECs, and promoted cutaneous wound healing in vivo. Moreover, H-ADSCs and H-ADSCs-exos, which exhibited higher levels of H19, were found to be transcriptionally activated by HIF-1α. Mechanically, H-ADSCs carrying USP22 accounted for deubiquitinating and stabilizing HIF-1α. Additionally, H-ADSCs-exos improved cell proliferation, migration, and angiogenesis in H2O2-triggered HUVECs by activating USP22/HIF-1α axis and promoting H19 expression, which may provide a new clue for the clinical treatment of cutaneous wound healing.

This study investigated mogrol\'s impact on non-small cell lung cancer (NSCLC) radiosensitivity and underlying mechanisms, using various methods including assays, bioinformatics, and xenograft models. CCK-8, clonogenic, flow cytometry, TUNEL, and Western blot assays evaluated mogrol and radiation effects on NSCLC viability and apoptosis. Ubiquitin-specific protease 22 (USP22) expression in NSCLC patient tissues was determined by RT-qPCR and Western blot. A xenograft model validated mogrol\'s effects on tumor growth. Bioinformatics identified four ubiquitin-specific proteases, including USP22, in NSCLC. Kaplan-Meier analysis confirmed USP22\'s value in lung cancer survival. Human Protein Atlas (HPA) database analysis indicated higher USP22 expression in lung cancer tissues. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis implicated ERK1/2 in NSCLC progression, and molecular docking showed stability between mogrol and ERK1/2. Further in vivo and in vitro experiments have demonstrated that mogrol enhances the inhibitory effect of radiation on NSCLC cell viability and clonogenic capacity. Cell viability and clonogenic capacity are reduced by >50%, and an increase in cellular apoptosis is observed, with apoptotic levels reaching 10%. USP22 expression was significantly elevated in NSCLC tissues, particularly in radiotherapy-resistant patients. Mogrol downregulated USP22 expression by inhibiting the ERK/CREB pathway, lowering COX2 expression. Mogrol also enhanced radiation\'s inhibition of tumor growth in mice. Mogrol enhances NSCLC radiosensitivity by downregulating USP22 via the ERK/CREB pathway, leading to reduced COX2 expression.NEW & NOTEWORTHY Mogrol enhances non-small cell lung cancer (NSCLC) cell sensitivity to radiotherapy by downregulating USP22 through the ERK/CREB pathway, reducing COX2 expression. These findings highlight mogrol\'s potential as an adjunct to improve NSCLC radiotherapy and open avenues for further research and clinical applications.

Breast cancer (BC) is the most frequent tumor entity in women worldwide with a high chance of therapeutic response in early- and non-metastatic disease stages. Among all BC subtypes, triple-negative BC (TNBC) is the most challenging cancer subtype lacking effective molecular targets due to the particular enrichment of cancer stem cells (CSCs), frequently leading to a chemoresistant phenotype and metastasis. The Ubiquitin Specific Peptidase 22 (USP22) is a deubiquitinase that has been frequently associated with a CSC-promoting function and intimately implicated in resistance to conventional therapies, tumor relapse, metastasis and overall poor survival in a broad range of cancer entities, including BC. To date, though, the role of USP22 in TNBC has been only superficially addressed.
The current study utilized the MMTV-cre, Usp22fl/fl transgenic mouse model to study the involvement of USP22 in the stem cell-like properties of the growing mammary tissue. Additionally, we combined high-throughput transcriptomic analyses with publicly available patient transcriptomic data and utilized TNBC culture models to decipher the functional role of USP22 in the CSC characteristics of this disease.
Interestingly, we identified that USP22 promotes CSC properties and drug tolerance by supporting the oxidative phosphorylation program, known to be largely responsible for the poor response to conventional therapies in this particularly aggressive BC subtype.
This study suggests a novel tumor-supportive role of USP22 in sustaining cellular respiration to facilitate the drug-tolerant behavior of HER2+-BC and TNBC cells. Therefore, we posit USP22 as a promising therapeutic target to optimize standard therapies and combat the aggressiveness of these malignancies. Video Abstract.

BACKGROUND: Atherosclerosis (AS) is commonly regarded as a key driver accounted for the leading causes of morbidity and mortality among cardiovascular and cerebrovascular diseases. A growing body of evidence indicates that autophagy in macrophages involved in AS might be a potential therapeutic target. C1q/TNF-related protein 9 (CTRP9) has been proven to delay the progression of cardiovascular diseases. However, the relations between CTRP9 and Sirt1, as well as their effects on macrophages autophagy have not been fully explored.
METHODS: Macrophages were differentiated from mononuclear cells collected from peripheral blood samples of healthy donors. The in vitro AS models were constructed by ox-LDL treatment. Cell viability was determined by CCK-8 assay. Immunofluorescence assay of LC3 was implemented for evaluating autophagy activity. Oil Red O staining was performed for lipid accumulation detection. ELISA, cholesterol concentration assay and cholesterol efflux analysis were conducted using commercial kits. Cycloheximide assay was implemented for revealing protein stability. RT-qPCR was used for mRNA expression detection, and western blotting was performed for protein level monitoring.
RESULTS: CTRP9 attenuated impaired cell viability, autophagy inhibition and increased lipid accumulation induced by ox-LDL. Moreover, CTRP9 maintained Sirt1 protein level through enhancing its stability through de-ubiquitination, which was mediated by upregulated USP22 level. CRTP9 exerted its protective role in promoting autophagy and reducing lipid accumulation through the USP22/Sirt1 axis.
CONCLUSIONS: Collectively, CTRP9 alleviates lipid accumulation and facilitated the macrophages autophagy by upregulating USP22 level and maintaining Sirt1 protein expression, thereby exerting a protective role in AS progression in vitro.

The dysregulation of deubiquitination has been shown to affect the development of pre-eclampsia (PE). A disintegrin and metalloprotease 9 (ADAM9) plays roles in diverse physiological contexts, including PE. Here, this study aimed to investigate whether ADAM9 regulated trophoblast cell dysfunction through ubiquitin-specific protease 22 (USP22) deubiquitinase-mediated deubiquitination during PE.
Levels of genes and proteins were tested via qRT-PCR and western blotting assays. Cell proliferation, migration, and invasion were detected using cell counting kit-8, 5-ethynyl-2\'-deoxyuridine (EdU), flow cytometry, transwell and wound healing assays, respectively. Epithelial-mesenchymal transition related markers were assayed using western blotting. Proteins between USP22 and ADAM9 were identified by co-immunoprecipitation assay.
ADAM9 was highly expressed in PE patients, functionally, ADAM9 overexpression weakened the proliferation, migration, invasion, and EMT progression in trophoblast cells. Mechanistically, the deubiquitinase USP22 removed ubiquitination on ADAM9 and maintained its stability. Forced expression of USP22 also suppressed the proliferation and mobility in trophoblast cells. Moreover, the regulatory effects of USP22 on trophoblast cells were reversed by ADAM9 silencing. In addition, USP22 interacted with ADAM9 to regulate the activation of Wnt/β-catenin pathway.
ADAM9 was deubiquitinated and stabilized by USP22 and then suppressed the proliferation, migration, invasion, and EMT progression in trophoblast cells, indicating a new pathway of USP10/RUNX1 axis in PE process.

Deubiquitinases (DUBs) play important roles in various human cancers and targeting DUBs is considered as a novel anticancer therapeutic strategy. Overexpression of ubiquitin specific protease 7 and 22 (USP7 and USP22) are associated with malignancy, therapy resistance, and poor prognosis in many cancers. Although both DUBs are involved in the regulation of similar genes and signaling pathways, such as histone H2B monoubiquitination (H2Bub1), c-Myc, FOXP3, and p53, the interdependence of USP22 and USP7 expression has never been described. In the study, we found that targeting USP7 via either siRNA-mediated knockdown or pharmaceutical inhibitors dramatically upregulates USP22 in cancer cells. Mechanistically, the elevated USP22 occurs through a transcriptional pathway, possibly due to desuppression of the transcriptional activity of SP1 via promoting its degradation upon USP7 inhibition. Importantly, increased USP22 expression leads to significant activation of downstream signal pathways including H2Bub1 and c-Myc, which may potentially enhance cancer malignancy and counteract the anticancer efficacy of USP7 inhibition. Importantly, targeting USP7 further suppresses the in vitro proliferation of USP22-knockout (USP22-Ko) A549 and H1299 lung cancer cells and induces a stronger activation of p53 tumor suppressor signaling pathway. In addition, USP22-Ko cancer cells are more sensitive to a combination of cisplatin and USP7 inhibitor. USP7 inhibitor treatment further suppresses in vivo angiogenesis and tumor growth and induced more apoptosis in USP22-Ko cancer xenografts. Taken together, our findings demonstrate that USP7 inhibition can dramatically upregulate USP22 in cancer cells; and targeting USP7 and USP22 may represent a more effective approach for targeted cancer therapy, which warrants further study. Video Abstract.