The E3 ubiquitin ligase TRIM7 suppressed hepatocellular carcinoma progression by directly targeting Src protein

E3 Ubiquitin Ligase TRIM7 Alleviates LPS-Induced Acute Lung Injury via Inhibiting NLRP3 Inflammasome Activation

Acute lung injury (ALI) is a clinically common disease with high mortality, characterized by tissue damage caused by excessive activation of inflammation. TRIM7 is an E3 ligase that plays an important role in regulating viral infection, tumor progression, and innate immune response. Its function in ALI is unclear, however. In this study, lipopolysaccharide (LPS) was used to stimulate C57BL/6j mice and HULEC-5a cells to establish ALI models in vivo and in vitro. The results showed that TRIM7 expression was down-regulated during ALI. Furthermore, overexpressing TRIM7 in HULEC-5a cells relieved cell damage and inflammatory activation induced by LPS stimulation. TRIM7 knockdown has the opposite effect. Trim7-overexpressing mice were established by endotracheal injection of adeno-associated virus 6-Trim7 virus in vivo; the ALI model was then induced by LPS stimulation. We showed that overexpression of TRIM7 could alleviate lung tissue injury, pulmonary interstitial hemorrhage, increased alveolar and vascular permeability, inflammatory cell infiltration, and secretion of inflammatory factors induced by LPS stimulation. Mechanistically, TRIM7 has been shown to inhibit the expression of NOD-, LRR- and pyrin domain-containing 3 (NLRP3) and activation of the NLRP3 inflammasome. The regulatory effect of TRIM7 on ALI depends on the NLRP3 inflammasome. This investigation for the first time shows the inhibitory effect of TRIM7 on ALI and activation of the NLRP3 inflammasome, providing new targets and ideas for the mechanism research and treatment of ALI.

Fangchinoline suppresses hepatocellular carcinoma by regulating ROS accumulation via the TRIM7/Nrf2 signaling pathway

BACKGROUND

Dysregulation of redox homeostasis is associated with developing hepatocellular carcinoma (HCC). Oxidative stress (OS) is distinguished by the accumulation of ROS, which plays a variety of roles in cancer pathology. Fangchinoline (FAN), a bis-benzylisoquinoline alkaloid, has anti-cancer pharmacological activity. However, the regulatory mechanism of FAN on OS and whether it can inhibit HCC by mediating OS are still unclear.

HYPOTHESIS/PURPOSE

This paper aims to explore the effectiveness of FAN in preventing HCC via regulating OS and identify the underlying molecular mechanisms.

METHODS

We used the primary HCC mouse model and hepatoma cell line to explore the suppressive effect of FAN on hepatocarcinogenesis. To study the role of ROS in the anti-hepatocarcinoma effect of FAN in cell model and mouse model. The mechanism of FAN-induced nuclear factor erythroid 2-related factor 2 (Nrf2) pathway activation was studied through various techniques, including generation of Nrf2 and tripartite motif containing 7 (TRIM7) gene overexpressing or knockdown cell model, co-immunoprecipitation, immunohistochemistry and subcutaneous tumor xenograft models constructed by the stable TRIM7-overexpression HLE cells, etc. RESULTS: We showed that FAN significantly inhibited cell proliferation and hepatocarcinogenesis in HCC cells and primary HCC mouse model. The FAN-induced mitochondrial dysfunction promoted ROS accumulation, and using N-Acetylcysteine to clear ROS reversed the anti-HCC effects of FAN. We observed that FAN is capable of activating the Nrf2 pathway. This effect was thought to be due to the fact that, in response to the FAN-induced OS, the cancer cells created a feedback loop to stable Nrf2 via depressing the K48-linkage ubiquitination of it, which was caused by reduced binding of kelch-like ECH-associated protein 1 (Keap1) and Nrf2 and elevated TRIM7 expression. Indeed, overexpression of TRIM7 suppressed the anti-hepatocarcinoma effect of FAN.

CONCLUSION

The study determines the anti-liver cancer effect of FAN and first describes the positive regulatory effect of TRIM7 on Nrf2 signaling. We reveal that TRIM7/Nrf2 signaling served as a target of FAN-induced ROS accumulation in HCC, which helps to clarify the mechanism of action of FAN against HCC and provides a theoretical basis for FAN as an anti-cancer drug.

RNF113A as a poor prognostic factor promotes metastasis and invasion of cervical cancer through miR197/PRP19/P38MAPK signaling pathway

It has been discovered that aberrant expression of RNF113A plays a significant role in various diseases, including esophageal cancer, hepatocellular carcinoma, and X-linked trichothiodystrophy syndrome. Nevertheless, its functional implications in cervical cancer (CC) remain unclear. The objective of this study was to investigate the role of RNF113A in both the development and prognosis of CC. To achieve this objective, a total of sixty cases were included in the follow-up investigation. The findings revealed a significant up-regulation of RNF113A protein in CC tissues compared to paired paracancerous tissues, and a high expression level of RNF113A was strongly associated with malignant phenotypes such as lymph node metastasis, differentiation degree, depth of invasion, and FIGO stage. Meanwhile, RNF113A was found to be an independent prognostic risk factor, with its high expression significantly correlating with a reduced overall survival period in patients. To elucidate the underlying cause and mechanism of the unfavorable prognosis associated with RNF113A, comprehensive functional investigations were conducted both in vitro and in vivo.Interestingly, it was revealed that RNF113A promoted migration and invasion while inhibiting apoptosis of CC cells, thereby contributing to a poor prognosis. Mechanistically, RNF113A regulated the progression and prognosis of CC through the miR197/Prp19/p38Mark signaling pathway. Overall, our findings underscore the potential clinical significance of RNF113A as an unfavorable prognostic factor in CC.

Exploring the potential mechanism of ginsenoside Rg1 to regulate ferroptosis in Alzheimer's disease based on network pharmacology

OBJECTIVES

To explore the pathogenesis of Alzheimer's disease (AD), the potential targets and signaling pathways of ginsenoside Rg1 against AD were investigated by network pharmacology.

METHODS

Ginsenoside Rg1 targets were identified through PubChem, PharmMapper, and Uniprot databases, while the GeneCards database was used to examine the respective targets of amyloid precursor protein (APP) and AD. Then, the common targets between ginsenoside Rg1 and APP were explored by the Venny tool, the interaction network diagram between the active components and the targets was built via Cytoscape software, as well as GO enrichment and KEGG pathway annotation analysis were performed. Furthermore, genes associated with ferroptosis were found by the GeneCards and FerrDb databases. Besides, the connection among ginsenoside Rg1, APP, ferroptosis, and AD was predicted and analyzed. Finally, the effects of ginsenosides Rg1 and liproxstain-1 on the proliferation and differentiation of APP/PS1 mice were evaluated by immunohistochemistry.

RESULTS

Ginsenoside Rg1, APP, ferroptosis, and AD had 12 hub genes. GO enrichment and KEGG pathway annotation analysis showed that EGFR, SRC, protein hydrolysis, protein phosphorylation, the Relaxin pathway, and the FoxO signaling pathway play an important role in the potential mechanism of ginsenoside Rg1's under regulation of ferroptosis anti-AD through the modulation of APP-related signaling pathways. The APP/PS1 mice experiment verified that ginsenosides Rg1 and liproxstain-1 can promote the proliferation and differentiation.

CONCLUSION

Ginsenoside Rg1, APP and ferroptosis may act on EGFR, SRC, the Relaxin and FoxO signaling pathways to regulate protein metabolism, protein phosphorylation and other pathways to improve AD symptoms.

The Dual Role of TRIM7 in Viral Infections

The E3 ubiquitin ligase TRIM7 is known to have dual roles during viral infections. Like other TRIM proteins, TRIM7 can regulate the IFN pathway via the regulation of the cytosolic receptors RIG-I or MDA-5, which promote the production of type I interferons (IFN-I) and antiviral immune responses. Alternatively, under certain infectious conditions, TRIM7 can negatively regulate IFN-I signaling, resulting in increased virus replication. A growing body of evidence has also shown that TRIM7 can, in some cases, ubiquitinate viral proteins to promote viral replication and pathogenesis, while in other cases it can promote degradation of viral proteins through the proteasome, reducing virus infection. TRIM7 can also regulate the host inflammatory response and modulate the production of inflammatory cytokines, which can lead to detrimental inflammation. TRIM7 can also protect the host during infection by reducing cellular apoptosis. Here, we discuss the multiple functions of TRIM7 during viral infections and its potential as a therapeutic target.

Ubiquitination and deubiquitination in cancer: from mechanisms to novel therapeutic approaches

Ubiquitination, a pivotal posttranslational modification of proteins, plays a fundamental role in regulating protein stability. The dysregulation of ubiquitinating and deubiquitinating enzymes is a common feature in various cancers, underscoring the imperative to investigate ubiquitin ligases and deubiquitinases (DUBs) for insights into oncogenic processes and the development of therapeutic interventions. In this review, we discuss the contributions of the ubiquitin-proteasome system (UPS) in all hallmarks of cancer and progress in drug discovery. We delve into the multiple functions of the UPS in oncology, including its regulation of multiple cancer-associated pathways, its role in metabolic reprogramming, its engagement with tumor immune responses, its function in phenotypic plasticity and polymorphic microbiomes, and other essential cellular functions. Furthermore, we provide a comprehensive overview of novel anticancer strategies that leverage the UPS, including the development and application of proteolysis targeting chimeras (PROTACs) and molecular glues.

Emerging roles of tripartite motif family proteins (TRIMs) in breast cancer

Breast cancer (BC) is the most common malignant tumor worldwide. Despite enormous progress made in the past decades, the underlying mechanisms of BC remain further illustrated. Recently, TRIM family proteins proved to be engaged in BC progression through regulating various aspects. Here we reviewed the structures and basic functions of TRIM family members and first classified them into three groups according to canonical polyubiquitination forms that they could mediate: K48- only, K63- only, and both K48- and K63-linked ubiquitination. Afterwards, we focused on the specific biological functions and mechanisms of TRIMs in BCs, including tumorigenesis and invasiveness, drug sensitivity, tumor immune microenvironment (TIME), cell cycle, and metabolic reprogramming. We also explored the potential of TRIMs as novel biomarkers for predicting prognosis and future therapeutic targets in BC.

TRIM47-CDO1 axis dictates hepatocellular carcinoma progression by modulating ferroptotic cell death through the ubiquitin‒proteasome system

Hepatocellular carcinoma (HCC) is the predominant form of liver cancer, characterized by high morbidity and mortality rates, as well as unfavorable treatment outcomes. Tripartite motif-containing protein 47 (TRIM47) has been implicated in various diseases including tumor progression with the activity of E3 ubiquitin ligase. However, the precise regulatory mechanisms underlying the involvement of TRIM47 in HCC remain largely unexplored. Here, we provide evidence that TRIM47 exhibits heightened expression in tumor tissues, and its expression is in intimate association with clinical staging and patient prognosis. TRIM47 promotes HCC proliferation, migration, and invasion as an oncogene by in vitro gain- and loss-of-function experiments. TRIM47 knockdown results in HCC ferroptosis induction, primarily through CDO1 involvement to regulate GSH synthesis. Subsequent experiments confirm the interaction between TRIM47 and CDO1 dependent on B30.2 domain, wherein TRIM47 facilitates K48-linked ubiquitination, leading to a decrease in CDO1 protein abundance in HCC. Furthermore, CDO1 is able to counteract the promotional effect of TRIM47 on HCC biological functions. Overall, our research provides novel insight into the mechanism of TRIM47 in CDO1-mediated ferroptosis in HCC cells, highlighting its value as a potential target candidate for HCC therapeutic approaches.

The E3 ligase TRIM7 suppresses the tumorigenesis of gastric cancer by targeting SLC7A11

Tripartite motif-containing protein 7 (TRIM7), as an E3 ligase, plays an important regulatory role in various physiological and pathological processes. However, the role of TRIM7 in gastric cancer (GC) is still undefined. Our study detected the expression of TRIM7 in clinical specimens and investigated the regulatory effect and molecular mechanism of TRIM7 on GC progression through in vitro and in vivo experiments. Our finding showed that TRIM7 was significantly downregulated in GC, and patients with high expression of TRIM7 showed long overall survival. Both in vitro and in vivo experiments showed that TRIM7 dramatically suppressed the malignant progression of GC. Further investigation showed that ferroptosis was the major death type mediated by TRIM7. Mechanistically, TRIM7 interacted with SLC7A11 through its B30.2/SPRY domain and promoted Lys48-linked polyubiquitination of SLC7A11, which effectively suppressing SLC7A11/GPX4 axis and inducing ferroptosis in GC cells. In vivo experiments and correlation analysis based on clinical specimens further confirmed that TRIM7 inhibited tumor growth through suppressing SLC7A11/GPX4 axis. In conclusion, our investigation demonstrated for the first time that TRIM7, as a tumor suppressor, induced ferroptosis via targeting SLC7A11 in GC, which provided a new strategy for the molecular therapy of GC by upregulating TRIM7.

The role of abnormal ubiquitination in hepatocellular carcinoma pathology

Primary liver cancer is known for its high incidence and fatality rate. Over the years, therapeutic strategies for primary liver cancer have advanced significantly. Nonetheless, a substantial number of patients have not benefited from these methods, underscoring the pressing need for new and effective treatments for primary liver cancer. Ubiquitination is a critical post-translational modification that enables proteins to fulfill their normal biological functions and maintain their expression stability within cells. Importantly, increasing evidence suggests that the progression of liver cancer cells is often accompanied by disruptions in protein ubiquitination and deubiquitination processes. In this comprehensive review, we have compiled pertinent research about dysregulated ubiquitination in hepatocellular carcinoma (HCC) to broaden our understanding in this field. We elucidate the connections between the ubiquitination proteasome system, deubiquitination, and HCC. Furthermore, we shed light on the role of ubiquitination in cells situated within the tumor microenvironment of HCC including its involvement in mediating the activation of oncogenic pathways, reprogramming metabolic processes, and perturbing normal cellular functions. In conclusion, targeting the dysregulation of ubiquitination in HCC holds promise as a prospective and complementary therapeutic approach to existing treatments.

TRIM22 induces cellular senescence by targeting PHLPP2 in hepatocellular carcinoma

The ubiquitin-proteasome system is a vital protein degradation system that is involved in various cellular processes, such as cell cycle progression, apoptosis, and differentiation. Dysregulation of this system has been implicated in numerous diseases, including cancer, vascular disease, and neurodegenerative disorders. Induction of cellular senescence in hepatocellular carcinoma (HCC) is a potential anticancer strategy, but the precise role of the ubiquitin-proteasome system in cellular senescence remains unclear. In this study, we show that the E3 ubiquitin ligase, TRIM22, plays a critical role in the cellular senescence of HCC cells. TRIM22 expression is transcriptionally upregulated by p53 in HCC cells experiencing ionizing radiation (IR)-induced senescence. Overexpression of TRIM22 triggers cellular senescence by targeting the AKT phosphatase, PHLPP2. Mechanistically, the SPRY domain of TRIM22 directly associates with the C-terminal domain of PHLPP2, which contains phosphorylation sites that are subject to IKKβ-mediated phosphorylation. The TRIM22-mediated PHLPP2 degradation leads to activation of AKT-p53-p21 signaling, ultimately resulting in cellular senescence. In both human HCC databases and patient specimens, the levels of TRIM22 and PHLPP2 show inverse correlations at the mRNA and protein levels. Collectively, our findings reveal that TRIM22 regulates cancer cell senescence by modulating the proteasomal degradation of PHLPP2 in HCC cells, suggesting that TRIM22 could potentially serve as a therapeutic target for treating cancer.

The role of ubiquitination and deubiquitination in PI3K/AKT/mTOR pathway: A potential target for cancer therapy

The PI3K/AKT/mTOR pathway controls key cellular processes, including proliferation and tumor progression, and abnormally high activation of this pathway is a hallmark in human cancers. The post-translational modification, such as Ubiquitination and deubiquitination, fine-tuning the protein level and the activity of members in this pathway play a pivotal role in maintaining normal physiological process. Emerging evidence show that the unbalanced ubiquitination/deubiquitination modification leads to human diseases via PI3K/AKT/mTOR pathway. Therefore, a comprehensive understanding of the ubiquitination/deubiquitination regulation of PI3K/AKT/mTOR pathway may be helpful to uncover the underlying mechanism and improve the potential treatment of cancer via targeting this pathway. Herein, we summarize the latest research progress of ubiquitination and deubiquitination of PI3K/AKT/mTOR pathway, systematically discuss the associated crosstalk between them, as well as focus the clinical transformation via targeting ubiquitination process.

Deciphering roles of TRIMs as promising targets in hepatocellular carcinoma: current advances and future directions

Tripartite motif (TRIM) family is assigned to RING-finger-containing ligases harboring the largest number of proteins in E3 ubiquitin ligating enzymes. E3 ubiquitin ligases target the specific substrate for proteasomal degradation via the ubiquitin-proteasome system (UPS), which seems to be a more effective and direct strategy for tumor therapy. Recent advances have demonstrated that TRIM genes associate with the occurrence and progression of hepatocellular carcinoma (HCC). TRIMs trigger or inhibit multiple biological activities like proliferation, apoptosis, metastasis, ferroptosis and autophagy in HCC dependent on its highly conserved yet diverse structures. Remarkably, autophagy is another proteolytic pathway for intracellular protein degradation and TRIM proteins may help to delineate the interaction between the two proteolytic systems. In depth research on the precise molecular mechanisms of TRIM family will allow for targeting TRIM in HCC treatment. We also highlight several potential directions warranted further development associated with TRIM family to provide bright insight into its translational values in hepatocellular carcinoma.

TRIM32 promotes oral squamous cell carcinoma progression by enhancing FBP2 ubiquitination and degradation

The aberrant expression of TRIM32, an E3 ubiquitin ligase, has been identified in multiple malignant cancer types. Nevertheless, the functional roles and detailed mechanisms of TRIM32 in oral squamous cell carcinoma (OSCC) remain to be elucidated. Here, we investigated TRIM32 expression and its functional role in OSCC. TRIM32 expression was consistently elevated in OSCC tissues, particularly in samples from patients with advanced clinical grades. Functionally, silencing TRIM32 dampened OSCC cell growth, migration and invasion. Additionally, a xenograft tumor model suggested that TRIM32 knockdown suppressed in vivo OSCC tumor growth and lung metastasis formation. Mechanistically, we discovered that TRIM32 directly bound to the FBP2 protein via mass spectrometry and co-immunoprecipitation. TRIM32 could interact with FBP2 and accelerates its degradation, eventually enhancing glycolysis in OSCC cell lines. Importantly, rescue assays demonstrated that FBP2 silencing could at least partially offset the tumor-suppressive and aerobic glycolysis inhibition effect induced by TRIM32 knockdown. Thus, our findings demonstrate that TRIM32 plays a crucial role in promoting tumor growth and enhancing glycolysis through FBP2 inhibition. Given OSCC is associated with increased glycolysis levels, our study suggests potential therapeutic targets for OSCC treatment.

The role of TRIM family in metabolic associated fatty liver disease

Metabolic associated fatty liver disease (MAFLD) ranks among the most prevalent chronic liver conditions globally. At present, the mechanism of MAFLD has not been fully elucidated. Tripartite motif (TRIM) protein is a kind of protein with E3 ubiquitin ligase activity, which participates in highly diversified cell activities and processes. It not only plays an important role in innate immunity, but also participates in liver steatosis, insulin resistance and other processes. In this review, we focused on the role of TRIM family in metabolic associated fatty liver disease. We also introduced the structure and functions of TRIM proteins. We summarized the TRIM family's regulation involved in the occurrence and development of metabolic associated fatty liver disease, as well as insulin resistance. We deeply discussed the potential of TRIM proteins as targets for the treatment of metabolic associated fatty liver disease.

TRIM55 Promotes Proliferation of Hepatocellular Carcinoma Through Stabilizing TRIP6 to Activate Wnt/β-Catenin Signaling

PURPOSE

Tripartite motif containing 55 (TRIM55) is a member of the TRIM family and functions as an E3 ubiquitin ligase. It acts as a cancer promoter or suppressor in the malignant processes of multiple cancers. However, its proliferative function in hepatocellular carcinoma (HCC) has been poorly studied, and its underlying molecular mechanism remains unclear. In the present study, we investigated the role of TRIM55 in HCC and its mechanism of promoting HCC proliferation.

MATERIALS AND METHODS

Protein expression levels of TRIM55 were measured in paired HCC and normal tissue samples using immunohistochemical (IHC) staining. The correlation between TRIM55 and clinical features was evaluated by statistical analysis. At the same time, overexpression and knockdown experiments, cycloheximide (CHX) interference experiments, ubiquitination, co-immunoprecipitation and immunofluorescence staining experiments, as well as animal experiments were used to evaluate the potential mechanism that TRIM55 promotes proliferation of hepatocellular carcinoma in vitro and in vivo.

RESULTS

TRIM55 expression in HCC specimens was higher compared with the corresponding non-tumor tissues. The overall survival and disease-free survival time of patients with high TRIM55 expression were shorter than those with low expression of TRIM55. Functionally, TRIM55 promoted the proliferation of HCC cells and accelerated the growth of HCC xenografts. Mechanistically, TRIM55 interacted with thyroid receptor interacting protein 6 (TRIP6) and regulate its stability by influencing the ubiquitination process, thereby affecting the Wnt signaling pathway.

CONCLUSION

Our results indicate that TRIM55 promotes HCC proliferation by activating Wnt signaling pathways by stabilizing TRIP6. Therefore, targeting TRIM55 may be an effective therapeutic strategy to inhibit HCC growth.

TRIM28 promotes the escape of gastric cancer cells from immune surveillance by increasing PD-L1 abundance

Immune checkpoint blockade (ICB) offers a new opportunity for treatment for gastric cancer (G.C.). Understanding the upstream regulation of immune checkpoints is crucial to further improve the efficacy of ICB therapy. Herein, using the CRISPR-Cas9-based genome-wide screening, we identified TRIM28 as one of the most significant regulators of PD-L1, a checkpoint protein, in G.C. cells. Mechanistically, TRIM28 directly binds to and stabilizes PD-L1 by inhibiting PD-L1 ubiquitination and promoting PD-L1 SUMOylation. Furthermore, TRIM28 facilitates K63 polyubiquitination of TBK1, activating TBK1-IRF1 and TBK1-mTOR pathways, resulting in enhanced PD-L1 transcription. It was found that TRIM28 was positively correlated with PD-L1 in G.C. cells. Moreover, high TRIM28 expression suggests poor survival in a cohort of 466 patients with G.C., and this observation is consistent while analyzing data from publicly available databases. Ectopic TRIM28 expression facilitated tumor growth, increased PD-L1 expression, and suppressed T cell activation in mice. Administration of the PD-L1 or TBK1 inhibitor significantly alleviated the TRIM28-induced tumor progression. Furthermore, combining the TBK1 inhibitor with CTLA4 immune checkpoint blockade has synergistic effects on G.C., and provides a novel strategy for G.C. therapy.

TRIM7/RNF90 promotes autophagy via regulation of ATG7 ubiquitination during L. monocytogenes infection

L. monocytogenes is a widely used infection model for the research on pathogenesis and host defense against gram-positive intracellular bacteria. Emerging evidence indicates that posttranslational modifications play a critical role in the regulation of macroautophagy/autophagy. However, little is known about the posttranslational modifications of ATG7, the essential protein in the autophagy process. In this study, we demonstrated that the RING-type E3 ligase TRIM7/RNF90 positively regulated autophagosome accumulation by promoting the ubiquitination of ATG7 at K413, thereby affecting L. monocytogenes infection. TRIM7 expression was induced by a variety range of conditions, including starvation, rapamycin stimulation, and L. monocytogenes infection. TRIM7 deficiency in mice or cells resulted in elevated innate immune responses and increased L. monocytogenes infection. ATG7 was associated with TRIM7 and the positive regulatory role of TRIM7 in L. monocytogenes infection-, starvation- or rapamycin-induced autophagosome accumulation was suggested by TRIM7 deficiency, TRIM7 overexpression, and TRIM7 knockdown. Further mechanistic investigation indicated that TRIM7 promoted the K63-linked ubiquitination of ATG7 at K413 and ubiquitination at this site was required for the function of ATG7 in autophagy and L. monocytogenes infection. Thus, our findings suggested a new regulator in intracellular bacterial infection and autophagy, with a novel posttranslational modification targeting ATG7. This research may expand our understanding of host anti-bacterial defense and the role of autophagy in intracellular bacterial infection.Abbreviations: ATG3: autophagy related 3; ATG5: autophagy related 5; ATG7: autophagy related 7; ATG10: autophagy related 10; ATG12: autophagy related 12; ATG16L1: autophagy related 16 like 1; Baf A1: bafilomycin A1; CQ: chloroquine; BMDC: bone marrow-derived dendritic cell; BMDM: bone marrow-derived macrophage; CFUs: colony-forming units; CXCL10/IP-10: C-X-C motif chemokine ligand 10; EBSS: Earle's balanced salt solution; ELISA: enzyme-linked immunosorbent assay; IFIT1/ISG56: interferon induced protein with tetratricopeptide repeats 1; IFNB/IFN-β: interferon beta; IL6: interleukin 6; IRF3, interferon regulatory factor 3; Lm: L. monocytogenes; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MEF: mouse embryonic fibroblast; MOI: multiplicity of infection; PLA: proximity ligation assay; PMA: phorbol myristate acetate; PMA-THP1, PMA-differentiated THP1; PMs: peritoneal macrophages; PTMs: posttranslational modifications; STING1, stimulator of interferon response cGAMP interactor 1; TBK1, TANK binding kinase 1; TNF/TNF-α: tumor necrosis factor; TRIM7/RNF90: tripartite motif containing; Hainan Provincial Natural Science Foundation of China.

Silencing RPL8 inhibits the progression of hepatocellular carcinoma by down-regulating the mTORC1 signalling pathway

This study aimed to explore the role of ribosomal protein L8 (RPL8) in controlling hepatocellular carcinoma (LIHC) development. We measured RPL8 expression, apoptosis, cell viability, proliferation, migration, invasion, glucose uptake, lactate production, and the ATP/ADP ratio of LIHC cells to investigate the effect of RPL8 on LIHC. Bioinformatic analysis was employed to analyse RPL8 expression and its potential mechanism in LIHC. RPL8 was upregulated in LIHC tissues and cells. RPL8 silencing accelerated apoptosis and suppressed viability, growth, and movement of LIHC cells. Additionally, RPL8 silencing inhibited glycolysis in LIHC cells. Bioinformatic analysis revealed that RPL8 is regulated by the upstream transcription factor upstream stimulating factor 1 (USF1) and activates the mTORC1 signalling pathway. USF1 overexpression eliminated the inhibitory effect of RPL8 silencing in LIHC cells. RPL8 overexpression increased cell growth, movement, and glycolysis in LIHC. However, inhibition of the mTORC1 signalling pathway eliminated the effect of RPL8 overexpression on LIHC cells. In conclusion, RPL8 may affect LIHC progression by regulating the mTORC1 signalling pathway.

Immune Pathways with Aging Characteristics Improve Immunotherapy Benefits and Drug Prediction in Human Cancer

(1) Background: Perturbation of immune-related pathways can make substantial contributions to cancer. However, whether and how the aging process affects immune-related pathways during tumorigenesis remains largely unexplored. (2) Methods: Here, we comprehensively investigated the immune-related genes and pathways among 25 cancer types using genomic and transcriptomic data. (3) Results: We identified several pathways that showed aging-related characteristics in various cancers, further validated by conventional aging-related gene sets. Genomic analysis revealed high mutation burdens in cytokines and cytokines receptors pathways, which were strongly correlated with aging in diverse cancers. Moreover, immune-related pathways were found to be favorable prognostic factors in melanoma. Furthermore, the expression level of these pathways had close associations with patient response to immune checkpoint blockade therapy in melanoma and non-small cell lung cancer. Applying a net-work-based method, we predicted immune- and aging-related genes in pan-cancer and utilized these genes for potential immunotherapy drug discovery. Mapping drug target data to our top-ranked genes identified potential drug targets, FYN, JUN, and SRC. (4) Conclusions: Taken together, our systematic study helped interpret the associations among immune-related pathways, aging, and cancer and could serve as a resource for promoting clinical treatment.

Prognostic value of tripartite motif (TRIM) family gene signature from bronchoalveolar lavage cells in idiopathic pulmonary fibrosis

BACKGROUND

Tripartite motif (TRIM) family genes get involved in the pathogenesis and development of various biological processes; however, the prognostic value of TRIM genes for idiopathic pulmonary fibrosis (IPF) needs to be explored.

METHODS

We acquired gene expression based on bronchoalveolar lavage (BAL) cells and clinical data of three independent IPF cohorts in the GSE70866 dataset from the Gene expression omnibus (GEO) database. Differentially expressed TRIM genes (DETGs) between IPF patients and healthy donors were identified and used to establish a risk signature by univariate and multivariate Cox regression analysis in the training cohort. The risk signature was further validated in other IPF cohorts, and compared with previously published signatures. Moreover, we performed functional enrichment analysis to explore the potential mechanisms. Eventually, the quantitative real time PCR was conducted to validate the expressions of the key genes in BAL from 12 IPF patients and 12 non-IPF controls from our institution.

RESULTS

We identified 4 DETGs including TRIM7, MEFV, TRIM45 and TRIM47 significantly associated with overall survival (OS) of IPF patients (P < 0.05). A multiple stepwise Cox regression analysis was performed to construct a 4-TRIM-gene prognostic signature. We categorized IPF patients into one low-risk group and the other high-risk group as per the average risk value of the TRIM prognostic signature in the training and validation cohorts. The IPF individuals in the low-risk group demonstrated an obvious OS advantage compared with the high-risk one (P < 0.01). The time-dependent receiver operating characteristic approach facilitated the verification of the predictive value of the TRIM prognostic signature in the training and validation cohorts, compared with other published signatures. A further investigation of immune cells and IPF survival displayed that higher proportion of resting memory CD4+ T cells and resting mast cells harbored OS advantage over lower proportion, however lower proportion of neutrophils, activated dendritic cells and activated NK cells indicated worse prognosis.

CONCLUSION

The TRIM family genes are significant for the prognosis of IPF and our signature could serve as a robust model to predict OS.

Study on the expression of TRIM7 in peripheral blood mononuclear cells of patients with sepsis and its early diagnostic value

Background

The early diagnosis of sepsis is beneficial to put forward a reasonable clinical treatment plan as soon as possible. This study was to explore the expression of Tripartite Motif 7 (TRIM7) in peripheral blood mononuclear cells (PBMCs) of patients with sepsis and its diagnostic value.

Methods

This is a cross-sectional study. A total of 69 patients with infectious diseases were enrolled in the emergency room. They were divided into the sepsis group (34 cases) and the non-sepsis infection group (35 cases). There were 25 healthy subjects who were selected as the control group. The expression of TRIM7 in PBMCs was observed by immunofluorescence staining. The correlation between the expression of TRIM7 mRNA and acute physiology and chronic health evaluation II (APACHE II) score, sequential organ failure assessment (SOFA) score, white blood cell (WBC), C-reactive protein (CRP), procalcitonin (PCT), tumor necrosis factor (TNF)-α and interleukin (IL)-6 was discussed. The receiver operating characteristic (ROC) curve was utilized for evaluating the value of TRIM7 expression for the early diagnosis of sepsis.

Results

The fluorescence intensity representing the expression level of TRIM7 in PBMCs of patients in the sepsis group was the lowest among three groups. The TRIM7 mRNA expression in PBMCs of the sepsis group was greatly decreased in comparison with that of the non-sepsis infection group and control group (P < 0.05). Spearman correlation analysis indicated that TRIM7 mRNA expression was negatively correlated with APACHE II score, SOFA score, WBC, CRP, PCT, TNF-α and IL-6. ROC curve analysis revealed that the area under curve (AUC) of TRIM7 mRNA expression in PBMCs for the diagnosis of sepsis was 0.798, with a 95% confidence interval of 0.691- 0.905, a sensitivity of 73.5%, and a specificity of 77.1%.

Conclusion

The expression of TRIM7 in PBMCs of patients with sepsis is significantly down-regulated, which has certain clinical value for early diagnosis of sepsis.

TRIM proteins in hepatocellular carcinoma

The tripartite motif (TRIM) protein family is a highly conserved group of E3 ligases with 77 members known in the human, most of which consist of a RING-finger domain, one or two B-box domains, and a coiled-coil domain. Generally, TRIM proteins function as E3 ligases to facilitate specific proteasomal degradation of target proteins. In addition, E3 ligase independent functions of TRIM protein were also reported. In hepatocellular carcinoma, expressions of TRIM proteins are both regulated by genetic and epigenetic mechanisms. TRIM proteins regulate multiple biological activities and signaling cascades. And TRIM proteins influence hallmarks of HCC. This review systematically demonstrates the versatile roles of TRIM proteins in HCC and helps us better understand the molecular mechanism of the development and progression of HCC.

TRIM7 modulates NCOA4-mediated ferritinophagy and ferroptosis in glioblastoma cells

Objective

Glioblastoma is one of the most common intracranial malignant tumors with an unfavorable prognosis, and iron metabolism as well as ferroptosis are implicated in the pathogenesis of glioblastoma. The present study aims to decipher the role and mechanisms of tripartite motif-containing protein 7 (TRIM7) in ferroptosis and glioblastoma progression.

Methods

Stable TRIM7-deficient or overexpressing human glioblastoma cells were generated with lentiviral vectors, and cell survival, lipid peroxidation and iron metabolism were evaluated. Immunoprecipitation, protein degradation and ubiquitination assays were performed to demonstrate the regulation of TRIM7 on its candidate proteins.

Results

TRIM7 expression was elevated in human glioblastoma cells and tissues. TRIM7 silence suppressed growth and induced death, while TRIM7 overexpression facilitated growth and inhibited death of human glioblastoma cells. Meanwhile, TRIM7-silenced cells exhibited increased iron accumulation, lipid peroxidation and ferroptosis, which were significantly reduced by TRIM7 overexpression. Mechanistically, TRIM7 directly bound to and ubiquitinated nuclear receptor coactivator 4 (NCOA4) using K48-linked chains, thereby reducing NCOA4-mediated ferritinophagy and ferroptosis of human glioblastoma cells. Moreover, we found that TRIM7 deletion sensitized human glioblastoma cells to temozolomide therapy.

Conclusion

We for the first time demonstrate that TRIM7 modulates NCOA4-mediated ferritinophagy and ferroptosis in glioblastoma cells, and our findings provide a novel insight into the progression and treatment for human glioblastoma.

TRIM7 Restricts Coxsackievirus and Norovirus Infection by Detecting the C-Terminal Glutamine Generated by 3C Protease Processing

TRIM7 catalyzes the ubiquitination of multiple substrates with unrelated biological functions. This cross-reactivity is at odds with the specificity usually displayed by enzymes, including ubiquitin ligases. Here we show that TRIM7's extreme substrate promiscuity is due to a highly unusual binding mechanism, in which the PRYSPRY domain captures any ligand with a C-terminal helix that terminates in a hydrophobic residue followed by a glutamine. Many of the non-structural proteins found in RNA viruses contain C-terminal glutamines as a result of polyprotein cleavage by 3C protease. This viral processing strategy generates novel substrates for TRIM7 and explains its ability to inhibit Coxsackie virus and norovirus replication. In addition to viral proteins, cellular proteins such as glycogenin have evolved C-termini that make them a TRIM7 substrate. The 'helix-ΦQ' degron motif recognized by TRIM7 is reminiscent of the N-end degron system and is found in ~1% of cellular proteins. These features, together with TRIM7's restricted tissue expression and lack of immune regulation, suggest that viral restriction may not be its physiological function.

Comprehensive Analysis of the Expression and Prognosis for Tripartite Motif-Containing Genes in Breast Cancer

Tripartite motif-containing genes (TRIMs), with a ubiquitin ligase’s function, play critical roles in antitumor immunity by activating tumor-specific immune responses and stimulating tumor proliferation, thus affecting patient outcomes. However, the expression pattern and prognostic values of TRIMs in breast cancer (BC) are not well clarified. In this study, several datasets and software were integrated to perform a comprehensive analysis of the expression pattern in TRIMs and investigate their prognosis values in BC. We found that TRIM59/46 were significantly upregulated and TRIM66/52-AS1/68/7/2/9/29 were decreased in BC and validated them using an independent cohort. The expression of numerous TRIMs are significantly correlated with BC molecular subtypes, but not with tumor stages or patient age at diagnosis. Higher expression of TRIM3/14/69/45 and lower expressions of TRIM68/2 were associated with better overall survival in BC using the Kaplan–Meier analysis. The multivariate Cox proportional hazards model identified TRIM45 as an independent prognostic marker. Further analysis of single-cell RNA-seq data revealed that most TRIMs are also expressed in nontumor cells. Higher expression of some TRIMs in the immune or stromal cells suggests an important role of TRIMs in the BC microenvironment. Functional enrichment of the co-expression genes indicates that they may be involved in muscle contraction and interferon-gamma signaling pathways. In brief, through the analysis, we provided several TRIMs that may contribute to the tumor progression and TRIM45 as a potential new prognostic biomarker for BC.

Targeting hypoxia-inducible factor pathways in sporadic and Von Hippel-Lindau syndrome-related kidney cancers

Hereditary and sporadic renal cell carcinomas (RCCs) are often associated with Von Hippel-Lindau (VHL)-gene inactivation. Patients with VHL disease have an increased risk of RCC, leading to bilateral nephrectomy and dialysis. In patients with advanced RCC, no standard second-lines are available after progression to immune checkpoint inhibitors (ICIs), and new agents are required to manage progression. HIFs have emerged as a promising target for metastatic RCC patients who have progressed to ICI-based combinations, as well as for those with RCC and VHL syndrome where the goal is to delay surgery and/or and preserve kidney function and avoid dialysis. This review describes the available evidence supporting the use of the small-molecule HIF-2 alpha inhibitor, belzutifan (MK-6482), as well as other new anti-HIF molecules that have demonstrated significant efficacy in VHL disease-related RCCs as well as for sporadic RCC that has progressed after the use of ICI-based combinations.

A prognostic risk model based on DNA methylation levels of genes and lncRNAs in lung squamous cell carcinoma

Background

Recurrence is a risk factor for the prognosis of lung squamous carcinoma (LUSC). DNA methylation levels of RNAs are also associated with LUSC prognosis. This study aimed to construct a prognostic model with high performance in predicting LUSC prognosis using the methylation levels of lncRNAs and genes.

Methods

The differentially expressed RNAs (DERs) and differentially methylated RNAs (DMRs) between the recurrent and non-recurrent LUSC tissues in The Cancer Genome Atlas (TCGA; training dataset) were identified. Weighted correlation network analysis was performed to identify co-methylation networks. Differentially methylated genes and lncRNAs with opposite expression-methylation levels were used for the screening of prognosis-associated RNAs. The prognostic model was constructed and its performance was validated in the GSE39279 dataset.

Results

A total of 664 DERs and 981 DMRs (including 972 genes) in recurrent LUSC tissues were identified. Three co-methylation modules, including 226 differentially methylated genes, were significantly associated with LUSC. Among prognosis-associated RNAs, 18 DERs/DMRs with opposite methylation-expression levels were included in the methylation prognostic risk model. LUSC patients with high risk scores had a poor prognosis compared with patients who had low risk scores (TCGA: HR = 3.856, 95% CI [2.297-6.471]; GSE39279: HR = 3.040, 95% CI [1.435-6.437]). This model had a high accuracy in predicting the prognosis (AUC = 0.903 and 0.800, respectively), equivalent to the nomogram model inclusive of clinical variables.

Conclusions

Referring to the methylation levels of the 16-RNAs might help to predict the survival outcomes in LUSC.

The roles of E3 ligases in Hepatocellular carcinoma

Hepatocarcinogenesis is a complex multistep biological process involving genetic and epigenetic alterations that are accompanied by activation of oncoproteins and inactivation of tumor suppressors, which in turn results in Hepatocellular carcinoma (HCC), one of the common tumors with high morbidity and mortality worldwide. The ubiquitin-proteasome system (UPS) is the key to protein degradation and regulation of physiological and pathological processes, and E3 ligases are key enzymes in the UPS that contain a variety of subfamily proteins involved in the regulation of some common signal pathways in HCC. There is growing evidence that many structural or functional dysfunctions of E3 are engaged in the development and progression of HCC. Herein, we review recent research advances in HCC-associated E3 ligases, describe their structure, classification, functional roles, and discuss some mechanisms of the abnormal activation or inactivation of the HCC-associated signal pathway due to the binding of E3 to known substrates. In addition, given the success of proteasome inhibitors in the treatment of malignant cancers, we characterize the current knowledge and future prospects for targeted therapies against aberrant E3 in HCC.

Comprehensive profiling of the TRIpartite motif family to identify pivot genes in hepatocellular carcinoma

INTRODUCTION

TRIpartite motif (TRIM) proteins are important members of the Really Interesting New Gene-finger-containing E3 ubiquitin-conjugating enzyme and are involved in the progression of hepatocellular carcinoma (HCC). However, the diverse expression patterns of TRIMs and their roles in prognosis and immune infiltrates in HCC have yet to be analyzed.

MATERIALS

Combined with previous research, we used an Oncomine database and the Human Protein Atlas to compare TRIM family genes' transcriptional levels between tumor samples and normal liver tissues, as verified by the Gene Expression Profiling Interactive Analysis database. We investigated the patient survival data of TRIMs from the Kaplan-Meier plotter database. Clinicopathologic characteristics associations and potential diagnostic and prognostic values were validated with clinical and expressional data collected from the cancer genome atlas.

RESULTS

We identified TRIM28, TRIM37, TRIM45, and TRIM59 as high-priority members of the TRIMs family that modulates HCC. Low expression of TRIM28 was associated with shorter overall survival (OS) than high expression (log-rank p = 0.009). The same trend was identified for TRIM37 (p = 0.001), TRIM45 (p = 0.013), and TRIM59 (p = 0.011). Multivariate analysis indicated that the level of TRIM37 was a significant independent prognostic factor for both OS (p = 0.043) and progression-free interval (p = 0.044). We performed expression and mutation analysis and functional pathways and tumor immune infiltration analysis of the changes in TRIM factors.

CONCLUSION

These data suggested that TRIM28, TRIM37, TRIM45, and TRIM59 could serve as efficient prognostic biomarkers and therapeutic targets in HCC.

HERC3 regulates epithelial-mesenchymal transition by directly ubiquitination degradation EIF5A2 and inhibits metastasis of colorectal cancer

E3 ligase is widely reported to exert fundamental functions in cancers. Through rigorous bioinformatic analysis concentrating E3 ligases based on data from Genotype-Tissue Expression (GTEx) and data from The Cancer Genome Atlas (TCGA), HERC3 was indicated to be downregulated in colorectal cancer (CRC) and HERC3 downregulation showed poor overall survival (OS) and disease-free survival (DFS). Through qRT-PCR, western blotting and Immunohistochemistry (IHC), analytical results were validated based on tissues in Zhongshan hospital. Functionally, HERC3 was indicated to inhibit the migration, invasion and metastasis in vitro and in vivo through transwell assays, wound healing assays and vivo experiments. And HERC3 could regulate epithelial-mesenchymal transition (EMT) in CRC. Furthermore, immunoprecipitation (IP), coimmunoprecipitation (co-IP) and GST-pulldown assays indicated that HERC3 could directly interact with EIF5A2 in vitro and in vivo through the RCC1 domain in HERC3. And HERC3 could function as an E3 to promote the K27 and K48-linked ubiquitination degradation of EIF5A2 via the HECT domain in HERC3, besides, K47, K67, K85, and K121 in EIF5A2 were identified as ubiquitination sites. In addition, HERC3 was indicated to affect the migration, invasion and metastasis and further regulatE EMT via EIF5A2/TGF-/Smad2/3 signal. The present study may provide insight into the mechanism of EMT in CRC.

TRIM7 suppresses cell invasion and migration through inhibiting HIF-1α accumulation in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is one frequent form of urologic malignancy characterized by deregulated hypoxia-inducible factor signaling, genetic and epigenetic alterations. Metastasis is the leading cause of mortality from ccRCC, and understanding the underlying mechanism of this event will provide better strategies for its management. Here, we identify tripartite motif containing 7 (TRIM7) as a tumor suppressor in ccRCC cells, which negatively regulates hypoxia-inducible factor 1α (HIF-1α) signaling through targeting the proto-oncogene Src. We observed the downregulated expression of TRIM7 in clinical ccRCC tissues and its correlation with the poor prognosis. In Caki-1 cells, depletion of TRIM7 increased cell migration and invasion under normoxic and hypoxic conditions. TRIM7 markedly reduced the abundance of Src protein via the ubiquitin-proteasome pathway. Further study showed that TRIM7 affected HIF-1α accumulation through targeting either the Src-triggered PI3K/AKT/mTOR signaling pathway or reactive oxygen species production. Overall, our findings highlight a novel mechanism for negative regulation of HIF-1 signaling pathway by TRIM7 and define a promising therapeutic strategy for ccRCC by modulating TRIM7.

Novel oncogenes and tumor suppressor genes in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a very deadly disease. HCC initiation and progression involve multiple genetic events, including the activation of proto-oncogenes and disruption of the function of specific tumor suppressor genes. Activation of oncogenes stimulates cell growth and survival, while loss-of-function mutations of tumor suppressor genes result in unrestrained cell growth. In this review, we summarize the new findings that identified novel proto-oncogenes and tumor suppressors in HCC over the past five years. These findings may inspire the development of novel therapeutic strategies to improve the outcome of HCC patients.

Inhibiting Src-mediated PARP1 tyrosine phosphorylation confers synthetic lethality to PARP1 inhibition in HCC

Hepatocellular carcinoma (HCC), a heterogeneous cancer with high mortality, is resistant to single targeted therapy; thus, combination therapy based on synthetic lethality is a promising therapeutic strategy for HCC. Poly (adenosine diphosphate [ADP]-ribose) polymerase 1 (PARP1) is the most recognized target for synthetic lethality; however, the therapeutic effect of PARP1 inhibition on HCC is disappointing. Therefore, exploring new synthetic lethal partners for the efficient manipulation of HCC is urgently required. In this study, we identified Src and PARP1 as novel synthetic lethal partners, and the combination therapy produced significant anti-tumor effects without causing obvious side effects. Mechanistically, Src interacted with PARP1 and phosphorylated PARP1 at the Y992 residue, which further mediated resistance to PARP1 inhibition. Overall, this study revealed that Src-mediated PARP1 phosphorylation induced HCC resistance to PARP1 inhibitors and indicated a therapeutic window of the Y992 phosphorylation of PARP1 for HCC patients. Moreover, synthetic lethal therapy by co-targeting PARP1 and Src have the potential to broaden the strategies for HCC and might benefit HCC patients with high Src activation and resistance to PARP1 inhibitors alone.

Pharmacological Modulation of Ubiquitin-Proteasome Pathways in Oncogenic Signaling

The ubiquitin-proteasome pathway (UPP) is involved in regulating several biological functions, including cell cycle control, apoptosis, DNA damage response, and apoptosis. It is widely known for its role in degrading abnormal protein substrates and maintaining physiological body functions via ubiquitinating enzymes (E1, E2, E3) and the proteasome. Therefore, aberrant expression in these enzymes results in an altered biological process, including transduction signaling for cell death and survival, resulting in cancer. In this review, an overview of profuse enzymes involved as a pro-oncogenic or progressive growth factor in tumors with their downstream signaling pathways has been discussed. A systematic literature review of PubMed, Medline, Bentham, Scopus, and EMBASE (Elsevier) databases was carried out to understand the nature of the extensive work done on modulation of ubiquitin-proteasome pathways in oncogenic signaling. Various in vitro, in vivo studies demonstrating the involvement of ubiquitin-proteasome systems in varied types of cancers and the downstream signaling pathways involved are also discussed in the current review. Several inhibitors of E1, E2, E3, deubiquitinase enzymes and proteasome have been applied for treating cancer. Some of these drugs have exhibited successful outcomes in in vivo studies on different cancer types, so clinical trials are going on for these inhibitors. This review mainly focuses on certain ubiquitin-proteasome enzymes involved in developing cancers and certain enzymes that can be targeted to treat cancer.

New biomarkers and therapeutic targets of human liver cancer: Transcriptomic findings

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related deaths worldwide, causing 782,000 deaths in 2018. Poor prognosis and lack of treatment are the reasons for the high mortality rate of HCC. In the current study, we conducted a comparative transcriptomic analysis, followed by a series of bioinformatics analyses, including Gene Ontology (GO) enrichment analysis and Ingenuity Pathway Analysis (IPA), aiming to unfold the detailed molecular mechanisms underlying the development of HCC. In the comparative transcriptomic analysis of 10 pairs of HCC tumoral tissues and adjunct nontumoral tissues, we identified 115 common differentially expressed genes in HCC. The GO enrichment analysis of these genes highlighted alterations in the immune response, cell proliferation and DNA damage, energetic metabolism, cell-matrix adhesion, and filament assembly in HCC. In addition, the canonical pathway analysis of IPA further showed the importance of many cell-signaling pathways involved in the carcinogenesis of HCC. The findings of this study provide a cluster of novel biomarkers and molecular therapeutic targets for HCC diagnosis and treatment.

Negative Regulation of RNF90 on RNA Virus-Triggered Antiviral Immune Responses Targeting MAVS

The antiviral innate immunity is the first line of host defense against viral infection. Mitochondrial antiviral signaling protein (MAVS, also named Cardif/IPS-1/VISA) is a critical protein in RNA virus-induced antiviral signaling pathways. Our previous research suggested that E3 ubiquitin-protein ligases RING-finger protein (RNF90) negatively regulate cellular antiviral responses by targeting STING for degradation, though its role in RNA virus infection remains unknown. This study demonstrated that RNF90 negatively regulated RNA virus-triggered antiviral innate immune responses in RNF90-silenced PMA-THP1 cells, RNF90-deficient cells (including HaCaTs, MEFs, and BMDMs), and RNF90-deficient mice. However, RNF90 regulated RNA virus-triggered antiviral innate immune responses independent of STING. RNF90 promoted K48-linked ubiquitination of MAVS and its proteasome-dependent degradation, leading to the inhibition of innate immune responses. Altogether, our findings suggested a novel function and mechanism of RNF90 in antiviral innate immunity.

Integrative proteomics reveals the role of E3 ubiquitin ligase SYVN1 in hepatocellular carcinoma metastasis

Background

Tumor metastasis is a major factor for poor prognosis of hepatocellular carcinoma (HCC), but the relationship between ubiquitination and metastasis need to be studied more systematically. We analyzed the ubiquitinome of HCC in this study to have a more comprehensive insight into human HCC metastasis.

Methods

The protein ubiquitination levels in 15 HCC specimens with vascular invasion and 15 without vascular invasion were detected by ubiquitinome. Proteins with significantly different ubiquitination levels between HCCs with and without vascular invasion were used to predict E3 ubiquitin ligases associated with tumor metastasis. The topological network of protein substrates and corresponding E3 ubiquitin ligases was constructed to identify the key E3 ubiquitin ligase. Besides, the growth, migration and invasion ability of LM3 and HUH7 hepatoma cell lines with and without SYVN1 expression interference were measured by cell proliferation assay, subcutaneous tumor assay, umphal vein endothelium tube formation assay, transwell migration and invasion assays. Finally, the interacting proteins of SYVN1 were screened and verified by protein interaction omics, immunofluorescence, and immunoprecipitation. Ubiquitin levels of related protein substrates in LM3 and HUH7 cells were compared in negative control, SYVN1 knockdown, and SYVN1 overexpression groups.

Results

In this study, our whole‐cell proteomic dataset and ubiquitinomic dataset contained approximately 5600 proteins and 12,000 ubiquitinated sites. We discovered increased ubiquitinated sites with shorter ubiquitin chains during the progression of HCC metastasis. In addition, proteomic and ubiquitinomic analyses revealed that high expression of E3 ubiquitin‐protein ligase SYVN1 is related with tumor metastasis. Furthermore, we found that SYVN1 interacted with heat shock protein 90 (HSP90) and impacted the ubiquitination of eukaryotic elongation factor 2 kinase (EEF2K).

Conclusions

The ubiquitination profiles of HCC with and without vascular invasion were significantly different. SYVN1 was the most important E3 ubiquitin‐protein ligase responsible for this phenomenon, and it was related with tumor metastasis and growth. Therefore, SYVN1 might be a potential therapeutic target for HCC.

TRIM7 inhibits enterovirus replication and promotes emergence of a viral variant with increased pathogenicity

To control viral infection, vertebrates rely on both inducible interferon responses and less well-characterized cell-intrinsic responses composed of "at the ready" antiviral effector proteins. Here, we show that E3 ubiquitin ligase TRIM7 is a cell-intrinsic antiviral effector that restricts multiple human enteroviruses by targeting viral 2BC, a membrane remodeling protein, for ubiquitination and proteasome-dependent degradation. Selective pressure exerted by TRIM7 results in emergence of a TRIM7-resistant coxsackievirus with a single point mutation in the viral 2C ATPase/helicase. In cultured cells, the mutation helps the virus evade TRIM7 but impairs optimal viral replication, and this correlates with a hyperactive and structurally plastic 2C ATPase. Unexpectedly, the TRIM7-resistant virus has a replication advantage in mice and causes lethal pancreatitis. These findings reveal a unique mechanism for targeting enterovirus replication and provide molecular insight into the benefits and trade-offs of viral evolution imposed by a host restriction factor.

MicroRNA-4491 enhances cell proliferation and inhibits cell apoptosis in non-small cell lung cancer via targeting TRIM7

MicroRNAs (miRNAs) are involved in the development of non-small cell lung cancer (NSCLC). However, the biological roles of several aberrantly expressed miRNAs have not been explored yet. In the present study, miR-4491 was identified as a novel upregulated miRNA in NSCLC tissues and cell lines. Downregulation of miR-4491 by a miR-4491 inhibitor inhibited the proliferation and triggered the apoptosis of NSCLC cells. Tripartite motif containing 7 (TRIM7), a tumor suppressor gene expressed in NSCLC, was demonstrated in the present study to be directly targeted by miR-4491. This finding was verified by bioinformatics analysis, reverse transcription-quantitative PCR, western blotting and dual luciferase reporter assays. Furthermore, downregulation of miR-4491 inactivated nuclear factor-κB signaling via induction of TRIM7. In addition, TRIM7 silencing attenuated the effect of miR-4491 inhibitor in NSCLC cells. The decreased TRIM7 level in NSCLC tissues was negatively correlated with miR-4491 expression in NSCLC tissues. In conclusion, the findings from this study demonstrated that miR-4491 expression was upregulated in NSCLC tissues and cells and that miR-4491 may promote NSCLC progression via targeting TRIM7.

Identification of CDC20 as an immune infiltration-correlated prognostic biomarker in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a malignancy with a poor prognosis. E3 ubiquitin-protein ligases play essential roles in HCC, such as regulating progression, migration, and metastasis. We aimed to explore a hub E3 ubiquitin-protein ligase gene and verify its association with prognosis and immune cell infiltration in HCC. Cell division cycle 20 (CDC20) was identified as a hub E3 ubiquitin-protein ligase in HCC by determining the intersecting genes in a protein-protein interaction (PPI) network of differentially expressed genes (DEGs) using HCC data from the International Cancer Genome Consortium (ICGC) and the gene list of 919 E3 ubiquitin-protein ligases. DEGs and their correlations with clinicopathological features were explored in The Cancer Genome Atlas (TCGA), ICGC, and Gene Expression Omnibus (GEO) databases via the Wilcoxon signed-rank test. The prognostic value of CDC20 was illustrated by Kaplan-Meier (K-M) curves and Cox regression analyses. Subsequently, the correlation between CDC20 and immune infiltration was demonstrated via the Tumor Immune Estimation Resource (TIMER) and Gene Expression Profiling Interactive Analysis (GEPIA). CDC20 expression was significantly higher in HCC than in normal tissues (all P < 0.05). High CDC20 expression predicted a poor prognosis and might be an independent risk factor in HCC (P < 0.05). Additionally, CDC20 was correlated with the immune infiltration of CD8 + T cells, T cells (general), monocytes, and exhausted T cells. This study reveals the potential prognostic value of CDC20 in HCC and demonstrates that CDC20 may be an immune-associated therapeutic target in HCC because of its correlation with immune infiltration.

The translational values of TRIM family in pan-cancers: From functions and mechanisms to clinics

Cancer is the second leading cause of human death across the world. Tripartite motif (TRIM) family, with E3 ubiquitin ligase activities in majority of its members, is reported to be involved in multiple cellular processes and signaling pathways. TRIM proteins have critical effects in the regulation of biological behaviors of cancer cells. Here, we discussed the current understanding of the molecular mechanism of TRIM proteins regulation of cancer cells. We also comprehensively reviewed published studies on TRIM family members as oncogenes or tumor suppressors in the oncogenesis, development, and progression of a variety of types of human cancers. Finally, we highlighted that certain TRIM family members are potential molecular biomarkers for cancer diagnosis and prognosis, and potential therapeutic targets.

ORN: Inferring patient-specific dysregulation status of pathway modules in cancer with OR-gate Network

Pathway level understanding of cancer plays a key role in precision oncology. However, the current amount of high-throughput data cannot support the elucidation of full pathway topology. In this study, instead of directly learning the pathway network, we adapted the probabilistic OR gate to model the modular structure of pathways and regulon. The resulting model, OR-gate Network (ORN), can simultaneously infer pathway modules of somatic alterations, patient-specific pathway dysregulation status, and downstream regulon. In a trained ORN, the differentially expressed genes (DEGs) in each tumour can be explained by somatic mutations perturbing a pathway module. Furthermore, the ORN handles one of the most important properties of pathway perturbation in tumours, the mutual exclusivity. We have applied the ORN to lower-grade glioma (LGG) samples and liver hepatocellular carcinoma (LIHC) samples in TCGA and breast cancer samples from METABRIC. Both datasets have shown abnormal pathway activities related to immune response and cell cycles. In LGG samples, ORN identified pathway modules closely related to glioma development and revealed two pathways closely related to patient survival. We had similar results with LIHC samples. Additional results from the METABRIC datasets showed that ORN could characterize critical mechanisms of cancer and connect them to less studied somatic mutations (e.g., BAP1, MIR604, MICAL3, and telomere activities), which may generate novel hypothesis for targeted therapy.

Crystal structure and mutational analysis of the human TRIM7 B30.2 domain provide insights into the molecular basis of its binding to glycogenin-1

Tripartite motif (TRIM)7 is an E3 ubiquitin ligase that was first identified through its interaction with glycogenin-1 (GN1), the autoglucosyltransferase that initiates glycogen biosynthesis. A growing body of evidence indicates that TRIM7 plays an important role in cancer development, viral pathogenesis, and atherosclerosis and, thus, represents a potential therapeutic target. TRIM family proteins share a multidomain architecture with a conserved N-terminal TRIM and a variable C-terminal domain. Human TRIM7 contains the canonical TRIM motif and a B30.2 domain at the C terminus. To contribute to the understanding of the mechanism of action of TRIM7, we solved the X-ray crystal structure of its B30.2 domain (TRIM7B30.2) in two crystal forms at resolutions of 1.6 Å and 1.8 Å. TRIM7B30.2 exhibits the typical B30.2 domain fold, consisting of two antiparallel β-sheets of seven and six strands, arranged as a distorted β-sandwich. Furthermore, two long loops partially cover the concave face of the β-sandwich defined by the β-sheet of six strands, thus forming a positively charged cavity. We used sequence conservation and mutational analyses to provide evidence of a putative binding interface for GN1. These studies showed that Leu423, Ser499, and Cys501 of TRIM7B30.2 and the C-terminal 33 amino acids of GN1 are critical for this binding interaction. Molecular dynamics simulations also revealed that hydrogen bond and hydrophobic interactions play a major role in the stability of a modeled TRIM7B30.2-GN1 C-terminal peptide complex. These data provide useful information that could be used to target this interaction for the development of potential therapeutic agents.

BUB1B promotes hepatocellular carcinoma progression via activation of the mTORC1 signaling pathway

Background and Aims

Accumulating studies identified that BUB1 mitotic checkpoint serine/threonine kinase B (BUB1B) is integrally involved in the initiation and development of tumors. Nevertheless, the precise biological role and underlying mechanisms of BUB1B in hepatocellular carcinoma (HCC) remain indistinct.

Method

To figure out the role of BUB1B in HCC, we first assessed its expression using The Cancer Genome Atlas (TCGA) and Gene Expression Profiling Interactive Analysis (GEPIA) databases. We then verified BUB1B expression in HCC tissues, nontumor tissues, and HCC cell lines through western blotting, quantitative reverse transcription‐polymerase chain reaction, and immunohistochemistry. To explore the specific function of BUB1B in HCC in vivo and in vitro, we performed the flow cytometry, Cell Counting Kit‐8, 5‐ethynyl‐2′‐deoxyuridine incorporation, colony formation, Transwell, wound‐healing, subcutaneous tumor growth, and metastasis assays. Additionally, we identified the BUB1B‐regulated pathways involved in HCC by using gene set enrichment analysis.

Results

Our data displayed that higher BUB1B expression was detected in HCC tissues and HCC cell lines. The overexpression of BUB1B was positively correlated with adverse clinicopathological characteristics. Survival analyses showed that lower recurrence‐free and overall survival rates were correlated with the overexpression of BUB1B in patients with HCC. Moreover, the malignancy of HCC was facilitated by BUB1B both in vivo and in vitro. Lastly, the results were confirmed by western blots, which showed that BUB1B upregulated mTORC1 signaling pathway in HCC. Meanwhile, the oncogenic effect of BUB1B will be impaired when the mTORC1 signaling pathway was inhibited by rapamycin.

Conclusion

We highlighted that BUB1B played an oncogenic role in HCC and was identified as a possible clinical prognostic factor and a potential novel therapeutic target for HCC.

N6-Methyladenosine modification of the TRIM7 positively regulates tumorigenesis and chemoresistance in osteosarcoma through ubiquitination of BRMS1

BACKGROUND

Metastasis is the leading cause of death in patients with osteosarcoma. Some of these patients fail to respond to chemotherapy and die of metastasis within a short period. Therefore, it is important to identify novel biomarkers to improve the diagnosis and treatment of osteosarcoma. TRIM7 is a member of the tripartite motif (TRIM) family protein that is involved in various pathological conditions including cancer; however, its role in osteosarcoma remains elusive.

METHODS

Cell proliferation, invasion and migration were measured by CCK-8 and Transwell. Immunoprecipitation and mass spectrometry analysis were used to identify candidate proteins associated with TRIM7. Immunoprecipitation, immunofluorescence, pull down and ubiquitination assay were performed to examine the regulation between TRIM7 and its candidate protein. m6A modification of TRIM7 was measured by RNA immunoprecipitation.

FINDINGS

TRIM7 expression was upregulated in osteosarcoma tissues and was an independent risk factor in predicting poor prognosis. TRIM7 regulates osteosarcoma cell migration and invasion through ubiquitination of breast cancer metastasis suppressor 1 (BRMS1). Moreover, chemoresistance was readily observed in osteosarcoma cells and in patient-derived xenograft (PDX) mice with higher TRIM7 levels. Loss of TRIM7 m6A modification was observed in osteosarcoma tissues. METTL3 and YTHDF2 were the main factors involved in the aberrant m6A modification of TRIM7.

INTERPRETATION

Overall, our findings show that TRIM7 plays a key role in regulating metastasis and chemoresistance in osteosarcoma through ubiquitination of BRMS1.

FUNDING

This work was financially supported by grants of NSFC (81001192, 81672658 and 81972521) and National Key Research Project of Science and Technology Ministry (2016YFC0106204).

The Effect of Dysfunctional Ubiquitin Enzymes in the Pathogenesis of Most Common Diseases

Ubiquitination is a multi-step enzymatic process that involves the marking of a substrate protein by bonding a ubiquitin and protein for proteolytic degradation mainly via the ubiquitin–proteasome system (UPS). The process is regulated by three main types of enzymes, namely ubiquitin-activating enzymes (E1), ubiquitin-conjugating enzymes (E2), and ubiquitin ligases (E3). Under physiological conditions, ubiquitination is highly reversible reaction, and deubiquitinases or deubiquitinating enzymes (DUBs) can reverse the effect of E3 ligases by the removal of ubiquitin from substrate proteins, thus maintaining the protein quality control and homeostasis in the cell. The dysfunction or dysregulation of these multi-step reactions is closely related to pathogenic conditions; therefore, understanding the role of ubiquitination in diseases is highly valuable for therapeutic approaches. In this review, we first provide an overview of the molecular mechanism of ubiquitination and UPS; then, we attempt to summarize the most common diseases affecting the dysfunction or dysregulation of these mechanisms.