CUL7 promotes cancer cell survival through promoting Caspase-8 ubiquitination

Ubiquitination in pyroptosis pathway: A potential therapeutic target for sepsis

Sepsis remains a significant clinical challenge, causing numerous deaths annually and representing a major global health burden. Pyroptosis, a unique form of programmed cell death characterized by cell lysis and the release of inflammatory mediators, is a crucial factor in the pathogenesis and progression of sepsis, septic shock, and organ dysfunction. Ubiquitination, a key post-translational modification influencing protein fate, has emerged as a promising target for managing various inflammatory conditions, including sepsis. This review integrates the current knowledge on sepsis, pyroptosis, and the ubiquitin system, focusing on the molecular mechanisms of ubiquitination within pyroptotic pathways activated during sepsis. By exploring how modulating ubiquitination can regulate pyroptosis and its associated inflammatory signaling pathways, this review provides insights into potential therapeutic strategies for sepsis, highlighting the need for further research into these complex molecular networks.

Longitudinal skeletal growth and growth plate morphological characteristics of chondro-tissue specific CUL7 knockout mice

BACKGROUND

3 M syndrome is first reported in 1975，which characterized by severe pre- and postnatal growth retardation, skeletal malformation and facial dysmorphism. These three genes (CUL7, OBSL1 and CCDC8) have been identified to be respond for 3 M syndrome, of which CUL7 is accounting for approximately 70%. To date, the molecular mechanism underlying the pathogenesis of 3 M syndrome remains poorly understood. Previous studies showed that no Cul7-/- mice could survive after birth, because of growth retardation at late gestational stage and respiratory distress after birth. The establishment of the animal model of cartilage specific Cul7 knockout mice (Cul7fl/fl;Col2a1-CreERT2 mice) has confirmed that Cul7fl/fl;Col2a1-CreERT2 mice can be selective in a time- and tissue-dependent manner, which can provide an experimental basis for further research on severe genetic diseases related to growth plates.

OBJECTIVE

To establish a model of Cul7fl/fl;Col2a1-CreERT2 mice based on Cre/LoxP system, and to further observe its phenotype and morphological changes in growth plate.

METHODS

The Cul7fl/fl;Col2a1-CreERT2 mice were taken as the experimental group, while the genotype of Cul7fl/+;Col2a1-CreERT2 mice were used as the control group. The gross morphological features and X-ray films of limbs in the two groups were observed every week for 3-6 consecutive weeks, and the length of the mice from nose to the tail, the length of femur and tibia were recorded. In the meantime, The histological morphology of tibial growth plates was compared between the two groups.

RESULTS

A preliminary model of Cul7fl/fl;Col2a1-CreERT2 mice was established. The Cul7fl/fl;Col2a1-CreERT2 mice had abnormally short and deformed limbs (P<0.05), increased thickness of growth plate, the disorderly arranged chondrocyte columns, decreased number of cells in the proliferation zone, changes in the shape from flat to round, obviously expanded extracellular matrix, and disordered arrangement, thickening and loosening of bone trabecula at the proximal metaphysis of the femur.

CONCLUSIONS

The knockout of Cul7 gene may affect both the proliferation of chondrocytes and the endochondral osteogenesis, confirming that Cul7 is essential for the normal development of bone in the body.

E3 ubiquitin ligases in cancer stem cells: key regulators of cancer hallmarks and novel therapeutic opportunities

BACKGROUND

Human malignancies are composed of heterogeneous subpopulations of cancer cells with phenotypic and functional diversity. Among them, a unique subset of cancer stem cells (CSCs) has both the capacity for self-renewal and the potential to differentiate and contribute to multiple tumor properties. As such, CSCs are promising cellular targets for effective cancer therapy. At the molecular level, hyper-activation of multiple stemness regulatory signaling pathways and downstream transcription factors play critical roles in controlling CSCs establishment and maintenance. To regulate CSC properties, these stemness pathways are controlled by post-translational modifications including, but not limited to phosphorylation, acetylation, methylation, and ubiquitination.

CONCLUSION

In this review, we focus on E3 ubiquitin ligases and their roles and mechanisms in regulating essential hallmarks of CSCs, such as self-renewal, invasion and metastasis, metabolic reprogramming, immune evasion, and therapeutic resistance. Moreover, we discuss emerging therapeutic approaches to eliminate CSCs through targeting E3 ubiquitin ligases by chemical inhibitors and proteolysis-targeting chimera (PROTACs) which are currently under development at the discovery, preclinical, and clinical stages. Several outstanding issues such as roles for E3 ubiquitin ligases in heterogeneity and phenotypical/functional evolution of CSCs remain to be studied under pathologically and clinically relevant conditions. With the rapid application of functional genomic and proteomic approaches at single cell, spatiotemporal, and even single molecule levels, we anticipate that more specific and precise functions of E3 ubiquitin ligases will be delineated in dictating CSC properties. Rational design and proper translation of these mechanistic understandings may lead to novel therapeutic modalities for cancer procession medicine.

Dual role of deubiquitinating enzyme USP19 regulates mitotic progression and tumorigenesis by stabilizing survivin

Survivin is a component of the chromosomal passenger complex, which includes Aurora B, INCENP, and Borealin, and is required for chromosome segregation and cytokinesis. We performed a genome-wide screen of deubiquitinating enzymes for survivin. For the first time, we report that USP19 has a dual role in the modulation of mitosis and tumorigenesis by regulating survivin expression. Our results found that USP19 stabilizes and interacts with survivin in HCT116 cells. USP19 deubiquitinates survivin protein and extends its half-life. We also found that USP19 functions as a mitotic regulator by controlling the downstream signaling of survivin protein. Targeted genome knockout verified that USP19 depletion leads to several mitotic defects, including cytokinesis failure. In addition, USP19 depletion results in significant enrichment of apoptosis and reduces the growth of tumors in the mouse xenograft. We envision that simultaneous targeting of USP19 and survivin in oncologic drug development would increase therapeutic value and minimize redundancy.

Identification and verification of the prognostic value of CUL7 in colon adenocarcinoma

CUL7, a gene composed of 26 exons associated with cullin 7 protein, is also an E3 ligase that is closely related to cell senescence, apoptosis, and cell transformation and also plays an important role in human cancer. However, there is no systematic pan-cancer analysis has been performed to explore its role in prognosis and immune prediction. In this study, the expression of CUL7 in colon adenocarcinoma (COAD) was investigated to determine its prognosis value. First, based on the Cancer Genome Atlas (TCGA), Genotypic-Tissue Expression Project(GTEx), Cancer Cell Line Encyclopedias(CCLE), and TISIDB database, the potential role of CUL7 in different tumors was explored. Subsequently, the expression of CUL7 in COAD was explored and verified by Immunohistochemistry (IHC). Furthermore, the mutation frequency of CUL7 in COAD was analyzed, and the prognostic value of CUL7 in COAD was discussed. In addition, the nomogram was constructed, and its prognostic value was verified by follow-up data from Jiangmen Central Hospital. Finally, PPI network analysis explored the potential biological function of CUL7 in COAD. The results show that CUL7 is upregulated in most tumors, which is significantly associated with poor survival. At the same time, CUL7 is correlated with the clinical stage and immune landscape of various tumors. In colorectal cancer, CUL7 was overexpressed in tumor tissues by IHC with a mutation frequency of about 4%. CUL7 is an independent prognostic factor for colorectal cancer. The nomogram constructed has effective predictive performance, and external databases proved the prognostic value of CUL7. In addition, PPI network analysis showed that CUL7 was closely related to FBXW8, and further pathway enrichment analysis showed that CUL7 was mainly involved in ubiquitin-mediated proteolysis. Therefore, our study provides a comprehensive understanding of the potential role of CUL7 in different tumors, and CUL7 might be a prognostic marker for COAD.

Whole Blood Transcriptional Fingerprints of High-Grade Glioma and Longitudinal Tumor Evolution under Carbon Ion Radiotherapy

Simple Summary

Particle therapy with carbon ions is a promising novel option for the treatment of recurrent high-grade glioma (rHGG). Lack of initial and sequential biopsies limits the investigation of rHGG evolution under therapy. We hypothesized that peripheral blood transcriptome derived from liquid biopsies (lbx) as a minimal invasive method may provide a useful decision support for identification of glioma grade and provide novel means for longitudinal molecular monitoring of tumor evolution under carbon ion irradiation (CIR). We demonstrate feasibility and report patient, tumor and treatment fingerprints in whole blood transcriptomes of rHGG patients with pre-CIR and three post-CIR time points.

Abstract

Purpose: To assess the value of whole blood transcriptome data from liquid biopsy (lbx) in recurrent high-grade glioma (rHGG) patients for longitudinal molecular monitoring of tumor evolution under carbon ion irradiation (CIR). Methods: Whole blood transcriptome (WBT) analysis (Illumina HumanHT-12 Expression BeadChips) was performed in 14 patients with rHGG pre re-irradiation (reRT) with CIR and 3, 6 and 9 weeks post-CIR (reRT grade III:5, 36%, IV:9, 64%). Patients were irradiated with 30, 33, 36 GyRBE (n = 5, 6, 3) in 3GyRBE per fraction. Results: WTB analysis showed stable correlation with treatment characteristics and patients tumor grade, indicating a preserved tumor origin specific as well as dynamic transcriptional fingerprints of peripheral blood cells. Initial histopathologic tumor grade was indirectly associated with TMEM173 (STING), DNA-repair (ATM, POLD4) and hypoxia related genes. DNA-repair, chromatin remodeling (LIG1, SMARCD1) and immune response (FLT3LG) pathways were affected post-CIR. Longitudinal WTB fingerprints identified two distinct trajectories of rHGG evolution, characterized by differential and prognostic CRISPLD2 expression pre-CIR. Conclusions: Lbx based WTB analysis holds the potential for molecular stratification of rHGG patients and therapy monitoring. We demonstrate the feasibility of the peripheral blood transcriptome as a sentinel organ for identification of patient, tumor characteristics and CIR specific fingerprints in rHGG.

Identification of Potential Genomic Alterations and the circRNA-miRNA-mRNA Regulatory Network in Primary and Recurrent Synovial Sarcomas

Introduction: Synovial sarcoma (SS) is one of the most invasive soft tissue sarcomas, prone to recurrence and metastasis, and the efficacy of surgical treatment and chemotherapy for SS remains poor. Therefore, the diagnosis and treatment of SS remain a significant challenge. This study aimed to analyze the mutated genes of primary SS (PSS) and recurrent SS (RSS), discover whether these sarcomas exhibit some potential mutated genes, and then predict associated microRNAs (miRNA) and circular RNAs (circRNA) by analyzing the mutated genes. We focused on the regulation mechanism of the circRNA-miRNA-mutated hub gene in PSS and RSS.

Methods: We performed a comprehensive genomic analysis of four pairs of formalin-fixed paraffin-embedded samples of PSS and RSS, using Illumina human exon microarrays. The gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) function, and pathway enrichment of the mutated genes were analyzed, and the protein-protein interaction (PPI) network was forecast using String software 11.0. The hub genes were then obtained using the Molecular Complex Detection (MCODE) plug-in for Cytoscape 3.7.2 and were used to analyze overall survival (OS) using the Gene Expression Profiling Interactive Analysis (GEPIA) database. The corresponding miRNAs were obtained from the miRDB 5.0 and TargetScan 7.2 databases. The corresponding circRNAs of the hub genes were found through the miRNAs from these databases: Circbank, CircInteractome, and StarBase v2.0. Thereafter we set up a competing endogenous RNA (ceRNA) network with circRNA-miRNA and miRNA-messenger RNA (mRNA) pairs.

Results: Using the chi-squared test, 391 mutated genes were screened using a significance level of p-values < 0.01 from the four pairs of PSS and RSS samples. A GO pathway analysis of 391 mutated genes demonstrated that differential expression mRNAs (DEmRNAs) might be bound up with the “positive regulation of neurogenesis,” “cell growth,” “axon part,” “cell−substrate junction,” or “protein phosphatase binding” of SS. The PPI network was constructed using 391 mutated genes, and 53 hub genes were identified (p < 0.05). Eight variant hub genes were discovered to be statistically significant using the OS analysis (p < 0.05). The circRNA-miRNA-mRNA (ceRNA) network was constructed, and it identified two circRNAs (hsa_circ_0070557 and hsa_circ_0070558), 10 miRNAs (hsa-let-7a-3p, hsa-let-7b-3p, hsa-let-7f-1-3p, hsa-let-7f-2-3p, hsa-mir-1244, hsa-mir-1197, hsa-mir-124-3p, hsa-mir-1249-5p, hsa-mir-1253, and hsa-mir-1271-5p) and five hub genes (CENPE, ENPP3, GPR18, MDC1, and PLOD2).

Conclusion: This study screened novel biological markers and investigated the differentiated circRNA-miRNA-mutated hub gene axis, which may play a pivotal role in the nosogenesis of PSS and RSS. Some circRNAs may be deemed new diagnostic or therapeutic targets that could be conducive to the future clinical treatment of SS.

Targeting NEDDylation as a Novel Approach to Improve the Treatment of Head and Neck Cancer

Head and neck cancer is diagnosed in nearly 900,000 new patients worldwide each year. Despite this alarming number, patient outcomes, particularly for those diagnosed with late-stage and human papillomavirus (HPV)-negative disease, have only marginally improved in the last three decades. New therapeutics that target novel pathways are desperately needed. NEDDylation is a key cellular process by which NEDD8 proteins are conjugated to substrate proteins in order to modulate their function. NEDDylation is closely tied to appropriate protein degradation, particularly proteins involved in cell cycle regulation, DNA damage repair, and cellular stress response. Components of the NEDDylation pathway are frequently overexpressed or hyperactivated in many cancer types including head and neck cancer, which contribute to disease progression and drug resistance. Therefore, targeting NEDDylation could have a major impact for malignancies with alterations in the pathway, and this has already been demonstrated in preclinical studies and clinical trials. Here, we will survey the mechanisms by which aberrant NEDDylation contributes to disease pathogenesis and discuss the potential clinical implications of inhibiting NEDDylation as a novel approach for the treatment of head and neck cancer.

Cullin-RING Ligases as Promising Targets for Gastric Carcinoma Treatment

Gastric carcinoma has serious morbidity and mortality, which seriously threats human health. The studies on gastrointestinal cell biology have shown that the ubiquitination modification that occurs after protein translation plays an essential role in the pathogenesis of gastric carcinoma. Protein ubiquitination is catalyzed by E3 ubiquitin ligase and can regulate various substrate proteins in different cellular pathways. Cullin-RING E3 ligase (CRLs) is a representative of the E3 ubiquitin ligase family, which requires cullin (CUL) neddylation modification for activation to regulate homeostasis of ~20% of cellular proteins. The substrate molecules regulated by CRLs are often involved in many cell progressions such as cell cycle progression, cell apoptosis, DNA damage and repair. Given that CRLs play an important role in modulation of biological activities, so targeting a certain CULs member neddylation may be an attractive strategy for selectively controlling the cellular proteins levels to achieve the goal of cancer treatment. In this review, we will discuss the roles of CULs and Ring protein in gastric carcinoma and summarize the current neddylation modulators for gastric carcinoma treatment.

DNA Methylation in Ovarian Cancer Susceptibility

Epigenetic alterations are somatically acquired over the lifetime and during neoplastic transformation but may also be inherited as widespread 'constitutional' alterations in normal tissues that can cause cancer predisposition. Epithelial ovarian cancer (EOC) has an established genetic susceptibility and mounting epidemiological evidence demonstrates that DNA methylation (DNAm) intermediates as well as independently contributes to risk. Targeted studies of known EOC susceptibility genes (CSGs) indicate rare, constitutional BRCA1 promoter methylation increases familial and sporadic EOC risk. Blood-based epigenome-wide association studies (EWAS) for EOC have detected a total of 2846 differentially methylated probes (DMPs) with 71 genes replicated across studies despite significant heterogeneity. While EWAS detect both symptomatic and etiologic DMPs, adjustments and analytic techniques may enrich risk associations, as evidenced by the detection of dysregulated methylation of BNC2-a known CSG identified by genome-wide associations studies (GWAS). Integrative genetic-epigenetic approaches have mapped methylation quantitative trait loci (meQTL) to EOC risk, revealing DNAm variations that are associated with nine GWAS loci and, further, one novel risk locus. Increasing efforts to mapping epigenome variation across populations and cell types will be key to decoding both the genomic and epigenomic causal pathways to EOC.

The functional analysis of Cullin 7 E3 ubiquitin ligases in cancer

Cullin (CUL) proteins have critical roles in development and cancer, however few studies on CUL7 have been reported due to its characteristic molecular structure. CUL7 forms a complex with the ROC1 ring finger protein, and only two F-box proteins Fbxw8 and Fbxw11 have been shown to bind to CUL7. Interestingly, CUL7 can interact with its substrates by forming a novel complex that is independent of these two F-box proteins. The biological implications of CUL-ring ligase 7 (CRL7) suggest that the CRL7 may not only perform a proteolytic function but may also play a non-proteolytic role. Among the existing studied CRL7-based E3 ligases, CUL7 exerts both tumor promotion and suppression in a context-dependent manner. Currently, the mechanism of CUL7 in cancer remains unclear, and no studies have addressed potential therapies targeting CUL7. Consistent with the roles of the various CRL7 adaptors exhibit, targeting CRL7 might be an effective strategy for cancer prevention and treatment. We systematically describe the recent major advances in understanding the role of the CUL7 E3 ligase in cancer and further summarize its potential use in clinical therapy.

Cullin-7 (CUL7) is overexpressed in glioma cells and promotes tumorigenesis via NF-κB activation

BACKGROUND

Cullin-7 (CUL7) is a member of the DOC domain-containing cullin family and is involved in the regulation of cell transformation. However, the clinical significance, potential mechanism and upstream regulators of CUL7 in malignant gliomas remain to be determined.

METHODS

Expression level data and clinical information were obtained via the Cancer Genome Atlas (TCGA) database, the Chinese Glioma Genome Atlas (CGGA) database, immunohistochemistry (IHC) and western blot analysis. Gene set enrichment analysis (GSEA) was used to explore the potential molecular mechanisms of CUL7. RNA silencing was performed using siRNA or lentiviral constructs in U87MG and U251 glioma cell lines and GSC267 glioma stem cells. CUL7 overexpression was performed using the GV141-CUL7 plasmid construct. In addition, overexpression of miR-3940-5p was performed and validated by quantitative real-time PCR (qRT-PCR). Cells were characterized in vitro or in vivo to evaluate their molecular status, cell proliferation, invasion, and migration by Cell Counting Kit (CCK)-8, EdU, flow cytometry, colony formation, Transwell and 3D tumour spheroid invasion assays. Coimmunoprecipitation (co-IP) and western blotting were performed to test the mechanisms of activation of the NF-κB signalling pathway.

RESULTS

High CUL7 expression was associated with a high tumour grade, a mesenchymal molecular glioma subtype and a poor prognosis in patients. Gene silencing of CUL7 in U87MG and U251 cells significantly inhibited tumour growth, invasion and migration in vitro and in vivo. Western blot analysis revealed that cyclin-dependent kinase inhibitors and epithelial-mesenchymal transition (EMT) molecular markers changed under CUL7 silencing conditions. In contrast, CUL7 overexpression promoted tumour growth, invasion and migration. Gene set enrichment analysis (GSEA) and western blot analysis revealed that CUL7 was positively associated with the NF-κB pathway. Moreover, with coimmunoprecipitation assays, we discovered that CUL7 physically associated with MST1, which further led to ubiquitin-mediated MST1 protein degradation, which promoted activation of the NF-κB signalling pathway. Finally, CUL7 was found to be downregulated by miR-3940-5p, which suppressed the development of gliomas.

CONCLUSIONS

Our findings indicate that CUL7 plays a significant role in promoting tumorigenesis via NF-κB activation and that it can be negatively regulated by miR-3940-5p in human gliomas. Furthermore, CUL7 might be a candidate molecular target for the treatment of glioma.

The role of E3 ubiquitin ligase HECTD3 in cancer and beyond

Ubiquitin modification plays significant roles in protein fate determination, signaling transduction, and cellular processes. Over the past 2 decades, the number of studies on ubiquitination has demonstrated explosive growth. E3 ubiquitin ligases are the key enzymes that determine the substrate specificity and are involved in cancer. Several recent studies shed light on the functions and mechanisms of HECTD3 E3 ubiquitin ligase. This review describes the progress in the recent studies of HECTD3 in cancer and other diseases. We propose that HECTD3 is a potential biomarker and a therapeutic target, and discuss the future directions for HECTD3 investigations.

Cullin-RING E3 Ubiquitin Ligase 7 in Growth Control and Cancer

CRL7^Fbxw8 is an E3 ubiquitin ligase complex, containing cullin7 (CUL7) as a scaffold, the F-box protein Fbxw8 as a substrate receptor, the Skp1 adaptor, and the ROC1/Rbx1 RING finger protein for working with E2 enzyme to facilitate ubiquitin transfer. This chapter provides an update on studies linking CRL7^Fbxw8 to hereditary human growth retardation disease, as at least 64 cul7 germ line mutations were found in patients with autosomal recessive 3-M syndrome. CRL7^Fbxw8 interacts with two additional 3-M associated proteins OBSL1 and CCDC8, leading to subcellular localization of the E3 complex to regions including plasma membrane, centrosome, and Golgi. At least ten mammalian cellular proteins were identified or implicated as CRL7^Fbxw8 substrates. Discussion focuses on the possible impact of CRL7^Fbxw8-mediated proteolytic or non-proteolytic pathways in growth control and cancer.

TRIM28 protects CARM1 from proteasome-mediated degradation to prevent colorectal cancer metastasis

TRIM28 (Tripartite motif-containing protein 28), a member of TRIM family, is aberrantly expressed and reportedly has different functions in many types of human cancer. However, the biological roles of TRIM28 and related mechanism in colorectal cancer (CRC) remain unclear. Here, we showed that TRIM28 was downregulated in colorectal cancer compared with normal mucosa, especially at advanced stages, and acted as an independent prognostic factor of favorable outcome. Functional studies demonstrated that TRIM28 restrained CRC migration and invasion in vitro and in vivo. Mechanistically, we reported that CARM1 (co-activator-associated arginine methyltransferase1) was a critical player downstream of TRIM28. TRIM28 interacted with CARM1, and protected CARM1 from proteasome-mediated degradation through physical protein-protein interaction to suppress CRC metastasis. Further, TRIM28 suppressed the migration and invasion of CRC cells through inhibiting WNT/β-catenin signaling in a CARM1-dependent manner, but independent of CARM1's methyltransferase activity. The protein expression of CARM1 was positively correlated with TRIM28 in CRC tissues. Patients with high levels of TRIM28 and CARM1 had improved prognosis, whereas patients with low TRIM28 and CARM1 expression had the poor outcomes. Thus, our study reveals an inhibitory role of TRIM28 in CRC metastasis, which was achieved through a TRIM28-CARM1-WNT/β-catenin axis. This work provides potential prognostic and therapeutic targets for CRC treatment.

Natural Product Mediated Regulation of Death Receptors and Intracellular Machinery: Fresh from the Pipeline about TRAIL-Mediated Signaling and Natural TRAIL Sensitizers

Rapidly developing resistance against different therapeutics is a major stumbling block in the standardization of therapy. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-mediated signaling has emerged as one of the most highly and extensively studied signal transduction cascade that induces apoptosis in cancer cells. Rapidly emerging cutting-edge research has helped us to develop a better understanding of the signaling machinery involved in inducing apoptotic cell death. However, excitingly, cancer cells develop resistance against TRAIL-induced apoptosis through different modes. Loss of cell surface expression of TRAIL receptors and imbalance of stoichiometric ratios of pro- and anti-apoptotic proteins play instrumental roles in rewiring the machinery of cancer cells to develop resistance against TRAIL-based therapeutics. Natural products have shown excellent potential to restore apoptosis in TRAIL-resistant cancer cell lines and in mice xenografted with TRAIL-resistant cancer cells. Significantly refined information has previously been added and continues to enrich the existing pool of knowledge related to the natural-product-mediated upregulation of death receptors, rebalancing of pro- and anti-apoptotic proteins in different cancers. In this mini review, we will set spotlight on the most recently published high-impact research related to underlying mechanisms of TRAIL resistance and how these deregulations can be targeted by natural products to restore TRAIL-mediated apoptosis in different cancers.