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Our previous study found that cullin 4B (CUL4B) inhibited rheumatoid arthritis (RA) pathology through glycogen synthase kinase-3beta (GSK3β)/canonical Wnt signalling pathway. in this work, pre-experiment and bioinformatics analysis suggested that circ_0011058 may lead to the up-regulation of CUL4B expression by inhibiting miR-335-5p. Therefore, we studied whether circ_0011058 can promote the expression of cUl4B through sponging the miR-335-5p and further promote the pathological development of RA. Bioinformatics prediction, real-time quantitative PCR (RT-qPCR), western blot (WB), double luciferase reporter gene and other relevant methods were used to study the inhibition of circ_0011058 on RA pathology and its molecular mechanism. Results showed that the expression of circ_0011058 was significantly increased in adjuvant arthritis (AA) rats and RA fibroblast-like synoviocytes (FLS). the knockout of circ_0011058 inhibited the proliferation of AA FLS and RA FLS, decreased the levels of interleukin-1 beta (IL-1β), interleukin 6 (IL-6), interleukin 8 (IL-8), and inhibited the expression of matrix metalloproteinase 3 (MMP3), fibronectin, which showed that circ_0011058 had a strong role in promoting RA pathology. Furthermore, miR-335-5p expression was reduced in AA rats and RA FLS. the highly expressed circ_0011058 directly sponged the miR-335-5p, which led to the increase of CUL4B expression and promoted the activation of the GSK3β/canonical signalling pathway. Finally, we confirmed that miR-335-5p mediated the roles of circ_0011058 in promoting RA pathological development, which showed that the circ_0011058/ miR-335-5p/CUL4B signal axis was involved in RA pathology. this work was of great significance for clarifying the roles of circ_0011058 in RA pathology, and further work was needed to establish whether circ_0011058 was a potential therapeutic target or diagnostic marker for RA. [ABSTRACT FROM AUTHOR]

Abstract CUL4B, a crucial scaffolding protein in the largest E3 ubiquitin ligase complex CRL4B, is involved in a broad range of physiological and pathological processes. While previous research has shown that CUL4B participates in maintaining intestinal homeostasis and function, its involvement in facilitating intestinal recovery following ionizing radiation (IR) damage has not been fully elucidated. Here, we utilized in vivo and in vitro models to decipher the role of CUL4B in intestinal repair after IR-injury. Our findings demonstrated that prior to radiation exposure, CUL4B inhibited the ubiquitination modification of PSME3, which led to the accumulation of PSME3 and subsequent negative regulation of p53-mediated apoptosis. In contrast, after radiation, CUL4B dissociated from PSME3 and translocated into the nucleus at phosphorylated histones H2A (γH2AX) foci, thereby impeding DNA damage repair and augmenting p53-mediated apoptosis through inhibition of BRCA1 phosphorylation and RAD51. Our study elucidated the dynamic role of CUL4B in the repair of radiation-induced intestinal damage and uncovered novel molecular mechanisms underlying the repair process, suggesting a potential therapeutic strategy of intestinal damage after radiation therapy for cancers.

CUL4B, a crucial scaffolding protein in the largest E3 ubiquitin ligase complex CRL4B, is involved in a broad range of physiological and pathological processes. While previous research has shown that CUL4B participates in maintaining intestinal homeostasis and function, its involvement in facilitating intestinal recovery following ionizing radiation (IR) damage has not been fully elucidated. Here, we utilized in vivo and in vitro models to decipher the role of CUL4B in intestinal repair after IR-injury. Our findings demonstrated that prior to radiation exposure, CUL4B inhibited the ubiquitination modification of PSME3, which led to the accumulation of PSME3 and subsequent negative regulation of p53-mediated apoptosis. In contrast, after radiation, CUL4B dissociated from PSME3 and translocated into the nucleus at phosphorylated histones H2A (γH2AX) foci, thereby impeding DNA damage repair and augmenting p53-mediated apoptosis through inhibition of BRCA1 phosphorylation and RAD51. Our study elucidated the dynamic role of CUL4B in the repair of radiation-induced intestinal damage and uncovered novel molecular mechanisms underlying the repair process, suggesting a potential therapeutic strategy of intestinal damage after radiation therapy for cancers. [ABSTRACT FROM AUTHOR]

Background: The role of the histone ubiquitination-related gene in the cisplatin resistance of lung adenocarcinoma (LUAD) remains an intricate subject. Methods: We accessed transcriptome data of both wild type and cisplatin-resistant cells from the GSE108214 dataset, and garnered transcriptome and clinical data of LUAD patients from The Cancer Genome Atlas (TCGA) database. Utilizing the R software, we analyzed these public datasets in depth. Real-time Quantitative PCR (qPCR) was used to detect the RNA level of CUL4B. Effect of CUL4B on cell proliferation was evaluated using CCK8 and colony formation assay. Effect of CUL4B on cell invasion was evaluated using transwell assay. Cisplatin sensitivity was evaluated by calculating IC50. Results: Our analysis shed light on the significance of the histone ubiquitination-related gene, CUL4B, in relation to cisplatin resistance and the overall survival rates of LUAD patients. Notably, CUL4B was found to be overexpressed in both lung cancer tissues and cells. Meanwhile, in vitro experiments indicated can CUL4B significantly promote the proliferation, invasion and migration of lung cancer cells. Furthermore, suppressing CUL4B expression led to a noticeable reduction in the IC50 value of cisplatin in lung cancer cells. A deep dive into biological enrichment analysis revealed that among patients exhibiting high CUL4B expression, there was a pronounced activation of the G2M checkpoint and the PI3K/AKT/mTOR signaling pathways. Immune microenvironment analysis has revealed that patients with elevated CUL4B expression may exhibit increased infiltration of M2 macrophages, coupled with a reduced infiltration of CD8+ T cells and activated NK cells. Notably, we observed higher CUL4B expression among those who responded positively to immunotherapy. Conclusion: These findings underscore the significance of CUL4B in the resistance to cisplatin in lung cancer, highlighting its potential as a therapeutic target. [ABSTRACT FROM AUTHOR]

Cullin 4B (CUL4B), which acts as a scaffold protein in CUL4B-RING ubiquitin ligase complexes (CRL4B), is frequently overexpressed in cancer and represses tumor suppressors through epigenetic mechanisms. However, the expression and function of CUL4B in esophageal squamous cell carcinoma (ESCC) have not been well illustrated. In this study, we show that upregulation of CUL4B in ESCC cells enhances proliferation, invasion and cisplatin (CDDP)-resistance, while knockdown of CUL4B significantly represses the malignant activities. Mechanistically, we demonstrate that CUL4B promotes proliferation and migration of ESCC cells through inhibiting expression of transforming growth factor beta receptor III (TGFBR3). CRL4B complex binds to the promoter of TGFBR3 , and represses its transcription by catalyzing monoubiquitination at H2AK119 and coordinating with PRC2 and HDAC complexes. Taken together, our findings establish a critical role for the CUL4B/TGFBR3 axis in the regulation of ESCC malignancy. • Upregulation of CUL4B enhances malignant phenotypes of ESCC cells. • Knockdown of CUL4B represses ESCC cell malignant activities. • CUL4B inhibits the expression of TGFBR3. • CUL4B bound to the promoter of TGFBR3, and epigenetically repressed its transcription. [ABSTRACT FROM AUTHOR]

Circular RNA (circRNA) regulates malignant tumors, including ovarian cancer (OC). The present research study aimed to reveal the biological mechanism of circRNA mitofusin 2 (circMFN2) in OC. Cell biological behaviors were investigated using clonogenicity assay, EdU assay, transwell assay, and flow cytometry analysis. Quantitative reverse transcription polymerase chain reaction (qRT‐PCR) and western blot analysis were implemented to detect the levels of circMFN2, miR‐198, Cullin 4B (CUL4B), and apoptosis‐related proteins. Glycolysis was assessed by glucose assay kit, lactate assay kit, and ATP level detection kit. The relationships among miR‐198, circMFN2, and CUL4B were verified by dual‐luciferase reporter assay and RNA immunoprecipitation assay. The xenograft mice model was used to analyze tumor growth in vivo. The expression of circMFN2 and CUL4B was increased, while miR‐330‐5p was decreased in OC tissues or cells. The absence of CircMFN2 hindered cell proliferation, migration, invasion, and glycolysis and promoted apoptosis in OC cells. We found that circMFN2 promoted CUL4B expression via sponging miR‐198. MiR‐198 depletion reversed circMFN2 knockdown‐induced effects in OC cells. Furthermore, CUL4B overexpression overturned the inhibitory effect of miR‐198 in OC cells. And the absence of circMFN2 inhibited tumor growth in vivo. CircMFN2 repressed OC progression by regulating the miR‐198/CUL4B axis. Highlights: CircMFN2 was upregulated in ovarian cancer (OC) tissues.CircSFMBT2 mediated CUL4B expression via sponging miR‐198.CircMFN2 knockdown inhibited OC cell development by the miR‐198/CUL4B axis. [ABSTRACT FROM AUTHOR]

Abstract Background Treatment failure is the main cause of death from papillary thyroid carcinoma (PTC). It is urgent to look for new intervention targets and to develop new therapies for treating PTC. Aurora-A kinase (AURKA) functionally regulates cell mitosis and is closely related to the occurrence and development of a variety of tumours. However, the expression and potential functions of AURKA in PTC remain largely elusive. Results Clinicopathologically, AURKA is highly expressed in PTC tissues compared to normal tissues and is correlated with lymph node metastasis, TNM stage and patient prognosis. Biologically, AURKA functions as an oncoprotein to promote the proliferation and migration of PTC cells. Mechanistically, AURKA directly binds to SIN1 and compromises CUL4B-based E3 ligase-mediated ubiquitination and subsequent degradation of SIN1, leading to hyperactivation of the mTORC2-AKT pathway in PTC cells. Conclusions We found that AURKA plays critical roles in regulating the progression of PTC by activating the mTORC2-AKT pathway, highlighting the potential of targeting AURKA to treat PTC.

Circular RNA lysine demethylase 4A (circKDM4A) is also named circ_0012098 and its abnormal expression has been confirmed in serum exosomes of prostate cancer (PC) patients. However, whether PC progression involves the exosomal circ_0012098 remains unknown. RNA expression of circKDM4A, microRNA-338-3p (miR-338-3p) and cullin 4B (CUL4B) was detected by quantitative real-time polymerase chain reaction. Protein expression was checked by Western blot. The positive expression rate of nuclear proliferation marker (ki-67) was analyzed by immunohistochemistry assay. Dual-luciferase reporter assay and RNA immunoprecipitation assay were used to identify the interaction between miR-338-3p and circKDM4A or CUL4B. Mouse model assay was performed to determine the effect of exosomal circKDM4A on tumorigenesis in vivo. CircKDM4A expression was significantly upregulated in the serum exosomes from PC patients compared with the exosomes from healthy volunteers. Exosomes treatment promoted the proliferation, migration and invasion of PC cells but inhibited apoptosis; however, these effects were attenuated after circKDM4A knockdown. Meanwhile, circKDM4A depletion restored exosome-increased circKDM4A expression. Additionally, circKDM4A acted as a miR-338-3p sponge, and miR-338-3p bound to CUL4B in PC cells. CircKDM4A regulated the effect of exosome-induced PC cell malignancy by interacting with miR-338-3p and CUL4B. Moreover, circKDM4A silencing relieved exosome-induced tumor growth in vivo. Exosomal circKDM4A promoted PC malignant progression by the miR-338-3p/CUL4B axis, providing a therapeutic target for PC. [ABSTRACT FROM AUTHOR]

• 43% of CUL4B patients develop seizures. • CUL4B -associated epilepsy may also be drug-resistant and persist beyond infancy. • Seizures can arise with different mutation types. • Neuroimaging features do not predict the development of epilepsy in CUL4 B patients. : Cabezas syndrome is a rare X-linked disease caused by mutations in CUL4B and characterized by developmental delay/intellectual disability, somatic dysmorphisms, behavioural disorder, ataxia/tremors. Although seizures have been formerly reported, their clinical semiology, EEG features and long-term outcome are largely unknown. This study aims to expand knowledge on epilepsy associated with Cabezas syndrome and to understand whether different types of variants in the CUL4B gene or brain MRI abnormalities may influence seizure onset and epilepsy course. With this in mind, we characterised the epileptic phenotype of a 17-year-old adolescent harbouring a CUL4B novel variant and performed a systematic literature review of CUL4B-associated seizures, analysing mutation types and neuroimaging features as epilepsy predictors. Our case observation indicates that CUL4B-associated epilepsy may also be drug-resistant and persist beyond infancy. Literature analysis shows that 43% of CUL4B patients develop seizures, with no statistically significant differences in epilepsy development according to mutation type and neuroimaging features. Our study extends knowledge of CUL4B-associated epilepsy, offering new insights into disease progression. [ABSTRACT FROM AUTHOR]

Lu Liu,1 Ruting Hui,2 Tianyang Zeng,3 Xuetao Yang,3 Qingchen Wu,3 Tao Yang3,4 1Intensive Care Unit of Thoracic and Cardiovascular Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, People’s Republic of China; 2Department of Rehabilitation Medicine, Chengdu First People’s Hospital, Chengdu, 61007, People’s Republic of China; 3Department of Thoracic and Cardiovascular Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, People’s Republic of China; 4Department of Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, CT, 06520, USACorrespondence: Tao Yang, Department of Thoracic and Cardiovascular Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, People’s Republic of China, Email xiangfei654@hotmail.comBackground: Malignant pleural mesothelioma (MPM) is a particularly fatal cancer with a median survival of less than one year. The value of single-agent checkpoint inhibitors is still obscure in MPM. We aim to reveal CUL4B prognostic role and immune infiltrates in MPM patients.Methods: CUL4B expression profile and clinical information of malignant pleura mesothelioma individuals were collected from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) dataset. Quantitative real-time PCR (qRT-PCR) analysis measured CUL4B mRNA expression in epithelioid, biphasic, sarcomatoid, and normal pleural cell lines.Results: CUL4B expression elevated in MPM and had a high diagnostic value with AUC = 0.772. Additionally, our results showed that CUL4B high expression significantly correlated with poorer outcomes in MPM. Moreover, GSEA revealed 15 KEGG pathways enriched in the CUL4B high-expression group, and 22 were exhibited in the CUL4B low-expression group. Otherwise, our results showed that CUL4B was relevant to Wnt antagonistic factors (BARX2), Insulin-like growth factor binding protein 3 (IGFBP3), and Phosphatase and tensin homolog (PTEN). In addition, our results revealed that CUL4B expression was positively linked with four types of immune cells, whereas CUL4B expression was negatively linked with three types of immune cells. Additionally, our results showed that CUL4B expression regulates T helper cells, Tcm, and Th2 cells infiltration MPM microenvironment. Finally, our results identified CUL4B high expression in MPM cell line NCI-H2052 (epithelioid), MSTO-211H (biphasic), and NCI-H28 (sarcomatoid).Conclusion: CUL4B is a valuable prognostic biomarker and a critical immune cell infiltration regulator in MPM.Keywords: malignant pleural mesothelioma, CUL4B, prognosis, tumorigenesis, immune infiltrates

Objective: Hepatitis B virus (HBV) infection is a major public health problem worldwide. However, the regulatory mechanisms underlying HBV replication remain unclear. Cullin 4B-RING ubiquitin E3 ligase (CRL4B) is involved in regulating diverse physiological and pathophysiological processes. In our study, we aimed to explain the role of CUL4B in HBV infection. Methods: Cul4b transgenic mice or conditional knockout mice, as well as liver cell lines with CUL4B overexpression or knockdown, were used to assess the role of CUL4B in HBV replication. Immunoprecipitation assays and immunofluorescence staining were performed to study the interaction between CUL4B and HBx. Cycloheximide chase assays and in vivo ubiquitination assays were performed to evaluate the half-life and the ubiquitination status of HBx. Results: The hydrodynamics-based hepatitis B model in Cul4b transgenic or conditional knockout mice indicated that CUL4B promoted HBV replication (P < 0.05). Moreover, the overexpression or knockdown system in human liver cell lines validated that CUL4B increased HBV replication in an HBx-dependent manner. Importantly, immunoprecipitation assays and immunofluorescence staining showed an interaction between CUL4B and HBx. Furthermore, CUL4B upregulated HBx protein levels by inhibiting HBx ubiquitination and proteasomal degradation (P < 0.05). Finally, a positive correlation between CUL4B expression and HBV pgRNA level was observed in liver tissues from HBV-positive patients and HBV transgenic mice. Conclusions: CUL4B enhances HBV replication by interacting with HBx and disrupting its ubiquitin-dependent proteasomal degradation. CUL4B may therefore be a potential target for anti-HBV therapy.

Background: Treatment failure is the main cause of death from papillary thyroid carcinoma (PTC). It is urgent to look for new intervention targets and to develop new therapies for treating PTC. Aurora-A kinase (AURKA) functionally regulates cell mitosis and is closely related to the occurrence and development of a variety of tumours. However, the expression and potential functions of AURKA in PTC remain largely elusive. Results: Clinicopathologically, AURKA is highly expressed in PTC tissues compared to normal tissues and is correlated with lymph node metastasis, TNM stage and patient prognosis. Biologically, AURKA functions as an oncoprotein to promote the proliferation and migration of PTC cells. Mechanistically, AURKA directly binds to SIN1 and compromises CUL4B-based E3 ligase-mediated ubiquitination and subsequent degradation of SIN1, leading to hyperactivation of the mTORC2-AKT pathway in PTC cells. Conclusions: We found that AURKA plays critical roles in regulating the progression of PTC by activating the mTORC2-AKT pathway, highlighting the potential of targeting AURKA to treat PTC. [ABSTRACT FROM AUTHOR]

Platinum‐based chemotherapy drugs play a very important role in the treatment of patients with advanced colorectal cancer, but the drug resistance of platinum‐based chemotherapy drugs is an important topic that puzzles us. If we can find mechanisms of resistance, it will be revolutionary for us. We analysed the differential genes, core genes and their enrichment pathways in platinum‐resistant and non‐resistant patients through a public database. Platinum‐resistant cell lines were cultured in vitro for in vitro colony and Transwell analysis. Tumorigenesis analysis of nude mice in vivo. Verify the function of core genes. Through differential gene and enrichment analysis, we found that CUL4B was the main factor affecting platinum drug resistance and EMT. Our hypothesis was further verified by in vitro drug‐resistant and wild‐type cell lines and in vivo tumorigenesis analysis of nude mice. CUL4B leads to platinum drug resistance in colorectal cancer by affecting tumour EMT. [ABSTRACT FROM AUTHOR]

Our previous study found that Cullin 4B (CUL4B) inhibited rheumatoid arthritis (RA) pathology through glycogen synthase kinase-3beta (GSK3β)/canonical Wnt signalling pathway. In this work, pre-experiment and bioinformatics analysis suggested that circ&#95;0011058 may lead to the up-regulation of CUL4B expression by inhibiting miR-335-5p. Therefore, we studied whether circ&#95;0011058 can promote the expression of CUL4B through sponging the miR-335-5p and further promote the pathological development of RA. Bioinformatics prediction, real-time quantitative PCR (RT-qPCR), western blot (WB), double luciferase reporter gene and other relevant methods were used to study the inhibition of circ&#95;0011058 on RA pathology and its molecular mechanism. Results showed that the expression of circ&#95;0011058 was significantly increased in adjuvant arthritis (AA) rats and RA fibroblast-like synoviocytes (FLS). The knockout of circ&#95;0011058 inhibited the proliferation of AA FLS and RA FLS, decreased the levels of interleukin-1 beta (IL-1β), interleukin 6 (IL-6), interleukin 8 (IL-8), and inhibited the expression of matrix metalloproteinase 3 (MMP3), fibronectin, which showed that circ&#95;0011058 had a strong role in promoting RA pathology. Furthermore, miR-335-5p expression was reduced in AA rats and RA FLS. The highly expressed circ&#95;0011058 directly sponged the miR-335-5p, which led to the increase of CUL4B expression and promoted the activation of the GSK3β/canonical signalling pathway. Finally, we confirmed that miR-335-5p mediated the roles of circ&#95;0011058 in promoting RA pathological development, which showed that the circ&#95;0011058/miR-335-5p/CUL4B signal axis was involved in RA pathology. This work was of great significance for clarifying the roles of circ&#95;0011058 in RA pathology, and further work was needed to establish whether circ&#95;0011058 was a potential therapeutic target or diagnostic marker for RA.

Estrogen receptor α (ERα) is the dominant tumorigenesis driver in breast cancer (BC), and ERα-positive BC (ERα+ BC) accounts for more than two-thirds of BC cases. MOF (males absent on the first) is a highly conserved histone acetyltransferase that acetylates lysine 16 of histone H4 (H4K16) and several non-histone proteins. Unbalanced expression of MOF has been identified, and high MOF expression predicted a favorable prognosis in BC. However, the association of MOF with ERα and the regulatory mechanisms of MOF in ERα signaling remain elusive. Our study revealed that the expression of MOF is negatively correlated with that of ERα in BC. In ERα+ BC cells, MOF overexpression downregulated the protein abundance of ERα in both cytoplasm and nucleus, thus attenuating ERα-mediated transactivation as well as cellular proliferation and in vivo tumorigenicity of BC cells. MOF promoted ERα protein degradation through CUL4B-mediated ubiquitin-proteasome pathway and induced HSP90 hyperacetylation that led to the loss of chaperone protection of HSP90 to ERα. We also revealed that suppression of MOF restored ERα expression and increased the sensitivity of ERα-negative BC cells to tamoxifen treatment. These results provide a new insight into the tumor-suppressive role of MOF in BC via negatively regulating ERα action, suggesting that MOF might be a potential therapeutic target for BC. [ABSTRACT FROM AUTHOR]

Abstract Mounting evidence has shown that long noncoding RNAs (lncRNAs) play critical roles in carcinogenesis and tumor progression. SNHG12 has been identified in multiple types of malignant tumors. However, the role of SNHG12 in human non‐small cell lung cancer (NSCLC) is poorly characterized, and the relevant underlying mechanism remains unclear. The expression levels of SNHG12, miR‐101‐3p, and CUL4B in collected human NSCLC tumor tissues and NSCLC cell lines were tested via qRT‐PCR. Then, NSCLC cellular proliferation, migration and invasion were determined, followed by MTT, scratch and Transwell assays. Dual‐luciferase reporter assays and RNA pulldown assays were adopted to explore the target site. Moreover, western blotting was performed to detect the relevant protein expression concerning the CUL4B/PI3K/AKT pathway. This study clarified that SNHG12 knockdown significantly reduced proliferation, migration, invasion and EMT of NSCLC cells. Our data indicated that SNHG12 targeted and negatively regulated miR‐101‐3p, and this depletion reversed the inhibitory effect of si‐SNHG12 on NSCLC cells. Furthermore, CUL4B was confirmed as a functional target of miR‐101‐3p, and its knockdown resulted in a strong alleviation of the NSLCL cell phenotype, which was enhanced by the silencing of miR‐101‐3p. Mechanistically, we found that SNHG12 regulated miR‐101‐3p to modulate the PI3K/AKT pathway mediated by CUL4B.These observations suggested that lncRNA SNHG12‐mediated miR‐101‐3p downregulation regulated the malignant phenotype of NSCLC cells by targeting CUL4B through the PI3K/AKT pathway, which may present a path to novel therapeutic strategies for NSCLC therapy.

Acute respiratory distress syndrome (ARDS) is a critical disease with a high mortality rate, characterized by obstinate hypoxemia caused by accumulation of alveolar fluid and excessive uncontrolled inflammation. Na,K-ATPase α1 (ATP1A1) subunit is an important component of Na,K-ATPase that transports Na+ and K+ and scavenges alveolar fluid. The function of Na,K-ATPase is always impaired during ARDS and results in more severe symptoms of ARDS. However, the regulatory mechanism of Na,K-ATPase after ARDS remains unclear. Here, we revealed ATP1A1 was downregulated post-transcriptionally by an E3 ligase component CUL4B mediated proteasomal degradation. Moreover, we found insulin could inhibit the upregulation of CUL4B in an insulin receptor cofactor HCF-1-dependent manner. Our study resolved the molecular mechanism underlying the clearance impairment of alveolar fluid and provided a clue for the usage of insulin as a potential therapeutic medicine for ARDS. [Display omitted] • CUL4B directly interacted with Na,K-ATPase α1 subunit in vivo. • Insulin effectively inhibited the upregulation of an E3 ligase component CUL4B caused by LPS. • CUL4B downregulated Na,K-ATPase α1 subunit post-transcriptionally via proteasomal degradation. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) within the periodontal ligament (PDL), termed periodontal ligament stem cells (PDLSCs), have a self-renewing capability and a multidirectional differentiation potential. The molecular mechanisms that regulate multidirectional differentiation, such as the osteogenic differentiation of PDLSCs, remain to be elucidated. Cullin 4B (CUL4B), which assembles the CUL4B-RING ubiquitin ligase (CRL4B) complex, is involved in regulating a variety of developmental and physiological processes including the skeletal development and stemness of cancer stem cells. However, nothing is known about the possible role of CUL4B in the osteogenic differentiation of PDLSCs. Here, we found that knockdown of CUL4B decreased the proliferation, migration, stemness and osteogenic differentiation ability of PDLSCs. Mechanistically, we demonstrate that CUL4B cooperates with the PRC2 complex to repress the expression of miR-320c and miR-372/373-3p, which results in the upregulation of RUNX2, a master transcription factor (TF) that regulates osteogenic differentiation. In brief, the present study reveals the role of CUL4B as a new regulator of osteogenic differentiation in PDLSCs.

Glioma multiforme (GBM) is the most common malignant primary brain tumors. Despite the considerable advances in GBM treatment, it is still one of the most lethal forms of brain tumor. New clinical biomarkers and therapeutic targets are immediately required. MicroRNAs (miRNAs) are a class of small, evolutionarily conserved noncoding RNAs and have emerged as the key regulators of many cancers. Here in this study, we showed that miR-674-5p was probably an important regulator of glioma cell growth. After the transfection with miR-674-5p mimic or inhibitor, we found that the expression level of miR-674-5p was negatively related with cell proliferation and migration in C6 cells. Based on the prediction of the target genes of miR-674-5p on the website, we chose Cullin 4B (Cul4b), a gene upregulated in GBM, and proved that it was a target of miR-674-5p. In addition, we explored the role of miR-674-5p in glioma growth in vivo. Taken together, the present study indicated that miR-674-5p suppressed glioma cell proliferation and migration by targeting Cul4b. [ABSTRACT FROM AUTHOR]

Background: Circular RNAs (circRNAs) are crucial regulators in human cancers, including non-small cell lung cancer (NSCLC). In this study, we explore the biological functions and molecular mechanisms of circ_0074027 in NSCLC. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to determine the expression of circ_0074027, paired like homeodomain 1 (PITX1) mRNA, microRNA-335-5p (miR-335-5p), and cullin 4B (CUL4B) mRNA. The features of circ_0074027 were analyzed by RNase R digestion assay. Flow cytometry analysis was adopted to analyze cell cycle and cell apoptosis. Cell counting kit-8 (CCK-8) assay and colony formation assay were performed to assess cell proliferation. Western blot assay was conducted to measure protein levels. Dual-luciferase reporter and RNA pull-down assays were carried out to verify the relationships among circ_0074027, miR-335-5p, and CUL4B. The murine xenograft model was established to investigate the role of circ_0074027 in vivo. Results: High expression of circ_0074027 was found in NSCLC tissues and cells. Circ_0074027 knockdown suppressed cell viability, cell cycle process, and colony formation and promoted apoptosis in NSCLC cells in vitro and inhibited tumor growth in vivo. Circ_0074027 acted as a sponge of miR-335-5p. The effect of circ_0074027 knockdown on NSCLC progression was weakened by miR-335-5p inhibition. Moreover, CUL4B was a target gene of miR-335-5p. CUL4B overexpression reversed the inhibitory effects on cell viability, cell cycle process, and colony formation and the promotional effect on cell apoptosis caused by miR-335-5p in NSCLC. Conclusion: Circ_0074027 facilitated NSCLC cell progression through regulating miR-335-5p/CUL4B axis. [ABSTRACT FROM AUTHOR]

Abstract Detecting clinical grade CNV based on WES is being improved in the NGS era.

Abstract Background Ovarian cancer (OC) is the gynecologic cancer with the highest mortality. Circular RNAs (circRNAs) play a vital role in the development and progression of cancer. This study aimed to explore the potential role of circ_0015756 in OC and its molecular mechanism. Methods The levels of circ_0015756, microRNA-942-5p (miR-942-5p) and Cullin 4B (CUL4B) were determined by quantitative real-time PCR (qRT-PCR) or Western blot assay. Cell proliferation, apoptosis, migration and invasion were assessed by Cell Counting Kit-8 (CCK-8), colony formation assay, flow cytometry and transwell assay. The levels of proliferation-related and metastasis-related proteins were measured by Western blot assay. The relationship between miR-942-5p and circ_0015756 or CUL4B was verified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Xenograft assay was used to analyze tumor growth in vivo. Results Circ_0015756 and CUL4B levels were increased, while miR-942-5p level was decreased in OC tissues and cells. Depletion of circ_0015756 suppressed proliferation, migration and invasion and promoted apoptosis in OC cells. Down-regulation of circ_0015756 hindered OC cell progression via modulating miR-942-5p. Also, up-regulation of miR-942-5p impeded OC cell development by targeting CUL4B. Mechanistically, circ_0015756 up-regulated CUL4B via sponging miR-942-5p. Moreover, circ_0015756 silencing inhibited tumor growth in vivo. Conclusion Knockdown of circ_0015756 suppressed OC progression via regulating miR-942-5p/CUL4B axis, suggesting that circ_0015756 might be a potential therapeutic target for ovarian cancer.

It was shown previously that inhibition of ERN1 (endoplasmic reticulum to nucleus signaling 1) pathway, a central mediator of the unfolded protein response, leads to suppression of tumor growth through down-regulation of key pro-proliferative and up-regulation of tumor suppressor factors and modifies the sensitivity of these genes to glucose and glutamine deprivation. However, the executive mechanisms of ERN1 mediated control of glioma cell proliferation are not yet known. The goal of this study was to estimate the effect of glucose and glutamine deprivations on expression of cancer related genes in glioma U87 cells at ERN1 signaling inhibition for evaluation of their possible significance in ERN1 mediated control of glioma cell proliferation. We have studied the effect of glucose and glutamine deprivations on the expression level of cancer related genes encoding TMED10 (transmembrane p24 trafficking protein 10), MYL9 (myosin, light chain 9, regulatory), SPOCK1 (sparc/osteonectin, cwcv and kazal-like domains proteoglycan 1), CUL4A (cullin 4A), and CUL4B in U87 glioma control cells and cells with ERN1 knockdown. It was shown that at glucose deprivation the expression level of MYL9, SPOCK1 and CUL4B genes was significantly up-regulated in control glioma cells. ERN1 knockdown modified the sensitivity to glucose deprivation of all studied genes except TMED10 gene. At glutamine deprivation the expression of MYL9, CUL4A and CUL4B genes was shown to be up-regulated in control glioma cells. The sensitivity of MYL9, TMED10 and CUL4B gene expression to glutamine deprivation in glioma cells with ERN1 knockdown was significantly modified, while CUL4A and SPOCK1 gene expression did not respond to ERN1 inhibition. The present study demonstrates that glucose and glutamine deprivation affected the expression of the most studied genes in a specific manner and that inhibition of ERN1 signaling preferentially modified their expression at glucose and glutamine deprivation.

Abstract Background Ovarian cancer is one of the most common malignant tumors in the female reproductive system with the highest mortality rate. Cul4B participates in the oncogenesis and progression of several malignant tumors. However, the role of Cul4B in ovarian cancer has not been studied. Results High expression of intratumor Cul4B was associated with poor patient survival. Cul4B expression was associated with FIGO stage and Cul4B was independent risk factor of ovarian cancer disease-free survival and overall survival. In vitro studies revealed that overexpression of Cul4B promoted tumor proliferation while knockdown of Cul4B significantly inhibited the proliferation capacity of ovarian cancer cells. Mechanistically, Cul4B was found to promotes cell entering S phase from G0/G1 phase by regulating the expression of CDK2 and CyclinD1. Cul4B regulates the expression of CDK2 and CyclinD1 by repressing miR-372. Conclusions The results revealed that high expression of Cul4B is associated with poor ovarian cancer prognosis and Cul4B may serve as a potential treating target for an adjuvant therapy.

Objective: The E3 ligase, CRL4, plays diverse roles in different cellular processes, such as DNA damage, transcriptional regulation, cell cycle progression, and cell apoptosis. Our previous study showed that CUL4A and CUL4B had a strong association with tobacco smoking risk in lung squamous cell carcinoma (SCC) and small cell lung carcinoma (SCLC). This study aimed to define the potential mechanism underlying the roles of CUL4A and CUL4B in the development of SCC and SCLC. Methods: We determined the role of CUL4A and CUL4B in the cell cycle and apoptosis of SCC and SCLC, and identified the key apoptosis-related gene involved in the oncogenic activity of CUL4B by Western blot, immunohistochemical staining, flow cytometry, and enzyme inhibition experiments. Results: We found that depletion of CUL4A and CUL4B reduced the proliferation of SCC and SCLC cells. CUL4Aknockdown but not CUL4Bknockdown arrested cells in G1 phase while upregulating P21 and CUL4Bknockdown promoted cell apoptosis through upregulation of FOXO3A. Accordingly, CUL4B decreased FOXO3A expression by activating the ERK signaling pathway and mediating FOXO3A degradation via the ubiquitin-proteasome pathway. Conclusions: These results identified the function of E3 ligase CRL4 in regulating SCC and SCLC cell proliferation, which provides a potential strategy for cancer therapy by targeting FOXO3A and the E3 ligase, CRL4.

Calcifying pseudoneoplasms of the neuraxis (CAPNON) are rare, slow‐growing, benign lesions occurring throughout the neuroaxis that are frequently misdiagnosed and overlooked by clinicians. Here, we report a case of a 56‐year‐old woman who presented with a history of recurrent headache for the previous six years. Magnetic resonance imaging (MRI) revealed a 2.3‐cm‐sized solid mass in the right frontal lobe that was surrounded by marked edematous areas. The lesion demonstrated dense calcification and avid enhancement. The lesion was initially diagnosed as oligodendroglioma, and then found to be CAPNON based on histopathology of a surgically resected tissue. Genetic analysis revealed a nonsense mutation in the CUL4B gene. The patient's condition appeared to reflect a reactive, rather than neoplastic, process. Clinicians should be prepared to detect such pseudotumors histopathologically in order to avoid unnecessary differential tests of neoplastic or infectious diseases, as well as potentially harmful therapies. [ABSTRACT FROM AUTHOR]

Variants in cullin 4B (CUL4B) are a known cause of syndromic X-linked intellectual disability. Here, we describe an additional 25 patients from 11 families with variants in CUL4B. We identified nine different novel variants in these families and confirmed the pathogenicity of all nontruncating variants. Neuroimaging data, available for 15 patients, showed the presence of cerebral malformations in ten patients. The cerebral anomalies comprised malformations of cortical development (MCD), ventriculomegaly, and diminished white matter volume. The phenotypic heterogeneity of the cerebral malformations might result from the involvement of CUL-4B in various cellular pathways essential for normal brain development. Accordingly, we show that CUL-4B interacts with WDR62, a protein in which variants were previously identified in patients with microcephaly and a wide range of MCD. This interaction might contribute to the development of cerebral malformations in patients with variants in CUL4B.

Mounting evidence has shown that long noncoding RNAs (lncRNAs) play critical roles in carcinogenesis and tumor progression. SNHG12 has been identified in multiple types of malignant tumors. However, the role of SNHG12 in human non‐small cell lung cancer (NSCLC) is poorly characterized, and the relevant underlying mechanism remains unclear. The expression levels of SNHG12, miR‐101‐3p, and CUL4B in collected human NSCLC tumor tissues and NSCLC cell lines were tested via qRT‐PCR. Then, NSCLC cellular proliferation, migration and invasion were determined, followed by MTT, scratch and Transwell assays. Dual‐luciferase reporter assays and RNA pulldown assays were adopted to explore the target site. Moreover, western blotting was performed to detect the relevant protein expression concerning the CUL4B/PI3K/AKT pathway. This study clarified that SNHG12 knockdown significantly reduced proliferation, migration, invasion and EMT of NSCLC cells. Our data indicated that SNHG12 targeted and negatively regulated miR‐101‐3p, and this depletion reversed the inhibitory effect of si‐SNHG12 on NSCLC cells. Furthermore, CUL4B was confirmed as a functional target of miR‐101‐3p, and its knockdown resulted in a strong alleviation of the NSLCL cell phenotype, which was enhanced by the silencing of miR‐101‐3p. Mechanistically, we found that SNHG12 regulated miR‐101‐3p to modulate the PI3K/AKT pathway mediated by CUL4B.These observations suggested that lncRNA SNHG12‐mediated miR‐101‐3p downregulation regulated the malignant phenotype of NSCLC cells by targeting CUL4B through the PI3K/AKT pathway, which may present a path to novel therapeutic strategies for NSCLC therapy. [ABSTRACT FROM AUTHOR]

Abstract Previous studies have revealed that CUL4B is overexpressed in various types of cancer and that its overexpression is related to the progression and metastasis of tumors. However, the biological functions of CUL4B in the progression of head and neck squamous cell carcinoma (HNSCC) are still not well understood. In the current study, we aimed to determine the changes in biological functions and molecular events that are related to CUL4B overexpression. Interestingly, our results showed that CUL4B is upregulated in HNSCC and that its upregulation is associated with poor survival and worse histological grade. Overexpression of CUL4B promoted cancer cell growth, invasion, and migration, as well as epithelial‐mesenchymal transition, whereas the loss of CUL4B abrogated these malignant phenotypes. Moreover, our mechanistic investigations suggest that the Wnt/β‐catenin signaling pathway was activated by CUL4B overexpression. Treatment with a Wnt/β‐catenin inhibitor decreased CUL4B‐induced migration and invasion, establishing a key role of Wnt/β‐catenin signaling in mediating the effects of CUL4B expression. Together, these results demonstrate a key contribution of CUL4B overexpression in the malignant behavior of HNSCC cells, at least in part through the stimulation of angiogenesis and the activation of the Wnt/β‐catenin signaling pathway.

Abstract Background Neural tube defects (NTDs) are common birth defects involving the central nervous system. Recent studies on the etiology of human NTDs have raised the possibility that epigenetic regulation could be involved in determining susceptibility to them. Results Here, we show that the H2AK119ub1 E3 ligase CUL4B is required for the activation of retinoic acid (RA)-inducible developmentally critical homeobox (HOX) genes in NT2/D1 embryonal carcinoma cells. RA treatment led to attenuation of H2AK119ub1 due to decrease in CUL4B, further affecting HOX gene regulation. Furthermore, we found that CUL4B interacted directly with RORγ and negatively regulated its transcriptional activity. Interestingly, knockdown of RORγ decreased the expression of HOX genes along with increased H2AK119ub1 occupancy levels, at HOX gene sites in N2/D1 cells. In addition, upregulation of HOX genes was observed along with lower levels of CUL4B-mediated H2AK119ub1 in both mouse and human anencephaly NTD cases. Notably, the expression of HOXA10 genes was negatively correlated with CUL4B levels in human anencephaly NTD cases. Conclusions Our results indicate that abnormal HOX gene expression induced by aberrant CUL4B-mediated H2AK119ub1 levels may be a risk factor for NTDs, and highlight the need for further analysis of genome-wide epigenetic modifications in NTDs.

Abstract Cullin4B (CUL4B) is a scaffold protein of the CUL4B‐Ring E3 ligase (CRL4B) complex. However, the role of CUL4B in the development of breast cancer remains poorly understood. Here it is shown that CRL4B interacts with multiple histone deacetylase (HDAC)‐containing corepressor complexes, including MTA1/NuRD, SIN3A, CoREST, and NcoR/SMRT complexes. It is demonstrated that CRL4B/NuRD(MTA1) complexes cooccupy the E‐cadherin and AXIN2 promoters, and could be recruited by transcription factors including Snail and ZEB2 to promote cell invasion and tumorigenesis both in vitro and in vivo. Remarkably, CUL4B responded to transformation and migration/invasion stimuli and is essential for multiple epithelial‐mesenchymal transition (EMT) signaling pathways such as hypoxia. Furthermore, the transcription of CUL4B is directedly activated by hypoxia‐inducible factor 1α (HIF1α) and repressed by the ERα‐GATA3 axis. Overexpressing of CUL4B successfully induced CSC‐like properties. Strikingly, CUL4B expression is markedly upregulated during breast cancer progression and correlated with poor prognosis. The results suggest that CUL4B lies at a critical crossroads between EMT and stem cell properties, supporting CUL4B as a potential novel target for the development of anti‐breast cancer therapy.

Resistance to temozolomide (TMZ), the first-line chemotherapeutic drug for glioblastoma (GBM) and anaplastic gliomas, is one of the most significant obstacles in clinical treatment. TMZ resistance is regulated by complex genetic and epigenetic networks. Understanding the mechanisms of TMZ resistance can help to identify novel drug targets and more effective therapies. CUL4B has been shown to be upregulated and promotes progression and chemoresistance in several cancer types. However, its regulatory effect and mechanisms on TMZ resistance have not been elucidated. The aim of this study was to decipher the role and mechanism of CUL4B in TMZ resistance. Western blot and public datasets analysis showed that CUL4B was upregulated in glioma specimens. CUL4B elevation positively correlated with advanced pathological stage, tumor recurrence, malignant molecular subtype and poor survival in glioma patients receiving TMZ treatment. CUL4B expression was correlated with TMZ resistance in GBM cell lines. Knocking down CUL4B restored TMZ sensitivity, while upregulation of CUL4B promoted TMZ resistance in GBM cells. By employing senescence β-galactosidase staining, quantitative reverse transcription PCR and Chromatin immunoprecipitation experiments, we found that CUL4B coordinated histone deacetylase (HDAC) to co-occupy the CDKN1A promoter and epigenetically silenced CDKN1A transcription, leading to attenuation of TMZ-induced senescence and rendering the GBM cells TMZ resistance. Collectively, our findings identify a novel mechanism by which GBM cells develop resistance to TMZ and suggest that CUL4B inhibition may be beneficial for overcoming resistance.

Objective To investigate the role of CUL4B-RING E3 ubiquitin ligase (CRL4B) complex in pancreatic tumorigenesis and the molecular mechanism. Methods Pancreatic cells were divided into control group (transfected with negative control lentivirus), shCUL4B group (transfected with CUL4B lentivirus), shDDB1 group [transfected with DNA damage binding protein 1 (DDB1) lentivirus], and shCUL4B+ siSFRP1 group (transfected with CUL4B lentivirus and SFRP1-siRNA). RNA-seq was performed in pancreatic cancer cell lines with CUL4B and DDB1 knocked down respectively, to identify the target genes regulated by CRL4B complex. Real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) was used to detect the mRNA expression levels of target genes. Chromatin immunoprecipitation (ChIP) assay was used to identify the target genes directly regulated by CUL4B and DDB1. Western blot was used to detect the protein expression levels of the epithelial-mesenchymal transition (EMT) markers. The EdU cell proliferation test was used to detect cell proliferation ability. The scratch repair test and Transwell cell invasion test were used to detect cell migration and invasion ability. Finally, the sequencing data of pancreatic cancer-related tumor samples and normal samples in GEO, TCGA and GTEx databases were used to analyze the expression correlations of CUL4B, DDB1 and their downstream target genes. Results RNA-seq results showed that target genes regulated by CRL4B complex involved in a number of malignant tumor-related signaling pathways. qRT-PCR results verified that the mRNA expression levels of the target genes of CUL4B or DDB1 knockdown groups were higher than those of the control group, and the difference was statistically significant (P<0.05). ChIP-PCR results showed that CRL4B complex directly bound to the promoter regions of the target genes, NME1 and SFRP1, and the enrichment of monoubiquitination of lysine at 119 of histone H2A (H2AK119ub1) in the promoter region of target gene was reduced after CUL4B knockdown. The proliferation rate in PANC-1 cell line of the control group was (32.10±3.58)%, higher than (13.95±1.66)% in the shCUL4B group and (22.38±0.77)% in the shCUL4B+ siSFRP1 group (P<0.05). The proliferation rate in AsPC-1 cell line of the control group was (35.47±7.80)%, higher than (19.60±3.58)% in the shCUL4B group and (30.09±0.81)% in the shCUL4B+ siSFRP1 group (P<0.05). The scratch repair experiment showed that the migration rate of PANC-1 cell line control group was (53.18±3.70)%, higher than that (17.46±2.62)% in the shCUL4B group and (44.99±9.18)% in the shCUL4B + siSFRP1 group (P<0.05). Western blot showed the expression levels of epithelial markers including α-catenin and γ-catenin in the control group were 1.00±0.03 and 1.01±0.11, respectively, lower than 1.44±0.01 and 1.21±0.06 in the shCUL4B group (P<0.05). The expression levels of mesenchymal markers including fibronectin and vimentin in the control group were 1.01±0.14 and 1.02±0.18, respectively, higher than 1.53±0.13 and 1.22±0.07 in the shCUL4B+ siSFRP1 group (P<0.05). The cell metastasis rate of the control group was (100.00±3.96)%, higher than the (35.49±0.34)% in the shCUL4B group and (107.06±2.77)% in the shCUL4B+ siSFRP1 group, the difference was statistically significant (P<0.05). The expressions of CUL4B and DDB1 were significantly upregulated in the pancreatic cancer tissues, and were negatively correlated with the expression of SFRP1 (r=-0.342 and r=-0.264, respectively). Conclusions CRL4B complex inhibits the transcription of target gene SFRP1 and promotes the development of pancreatic cancer. Moreover, CRL4B complex is upregulated in pancreatic cancer, which provide a potential of therapeutic target for pancreatic cancer. [ABSTRACT FROM AUTHOR]

Tamoxifen (TAM) resistance is a significant clinical challenge in endocrine therapies for estrogen receptor (ER)‐positive breast cancer patients. Cullin 4B (CUL4B), which acts as a scaffold protein in CUL4B–RING ubiquitin ligase complexes (CRL4B), is frequently overexpressed in cancer and represses tumor suppressors through diverse epigenetic mechanisms. However, the role and the underlying mechanisms of CUL4B in regulating drug resistance remain unknown. Here, we showed that CUL4B promotes TAM resistance in breast cancer cells through a miR‐32‐5p/ER‐α36 axis. We found that upregulation of CUL4B correlated with decreased TAM sensitivity of breast cancer cells, and knockdown of CUL4B or expression of a dominant‐negative CUL4B mutant restored the response to TAM in TAM‐resistant MCF7‐TAMR and T47D‐TAMR cells. Mechanistically, we demonstrated that CUL4B renders breast cancer cells TAM‐resistant by upregulating ER‐α36 expression, which was mediated by downregulation of miR‐32‐5p. We further showed that CRL4B epigenetically represses the transcription of miR‐32‐5p by catalyzing monoubiquitination at H2AK119 and coordinating with PRC2 and HDAC complexes to promote trimethylation at H3K27 at the promoter of miR‐32‐5p. Pharmacologic or genetic inhibition of CRL4B/PRC2/HDAC complexes significantly increased TAM sensitivity in breast cancer cells in vitro and in vivo. Taken together, our findings thus establish a critical role for the CUL4B–miR‐32‐5p–ER‐α36 axis in the regulation of TAM resistance and have important therapeutic implications for combined application of TAM and the inhibitors of CRL4B/PRC2/HDAC complex in breast cancer treatment. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Cullin4B (CUL4B) is a scaffold protein of the CUL4B‐Ring E3 ligase (CRL4B) complex. However, the role of CUL4B in the development of breast cancer remains poorly understood. Here it is shown that CRL4B interacts with multiple histone deacetylase (HDAC)‐containing corepressor complexes, including MTA1/NuRD, SIN3A, CoREST, and NcoR/SMRT complexes. It is demonstrated that CRL4B/NuRD(MTA1) complexes cooccupy the E‐cadherin and AXIN2 promoters, and could be recruited by transcription factors including Snail and ZEB2 to promote cell invasion and tumorigenesis both in vitro and in vivo. Remarkably, CUL4B responded to transformation and migration/invasion stimuli and is essential for multiple epithelial‐mesenchymal transition (EMT) signaling pathways such as hypoxia. Furthermore, the transcription of CUL4B is directedly activated by hypoxia‐inducible factor 1α (HIF1α) and repressed by the ERα‐GATA3 axis. Overexpressing of CUL4B successfully induced CSC‐like properties. Strikingly, CUL4B expression is markedly upregulated during breast cancer progression and correlated with poor prognosis. The results suggest that CUL4B lies at a critical crossroads between EMT and stem cell properties, supporting CUL4B as a potential novel target for the development of anti‐breast cancer therapy. [ABSTRACT FROM AUTHOR]

Although several molecular targeted therapy and immunotherapy have been developed, cutaneous melanoma prognosis is still not satisfying. Cul4b promotes the progression of several malignant tumors by regulating cell proliferation. However, its prognostic role in malignant cutaneous melanoma has not been evaluated. In this study, immunohistochemistry was performed to assess the expression of Cul4b in a consecutive patient cohort. The prognostic role of Cul4b was estimated with univariate and multivariate analysis. Cul4b was knocked down in melanoma cell line to evaluate its role in promoting cell proliferation. The results revealed that Cul4b was highly expressed in some of the cutaneous malignant melanoma patients and high expression of Cul4b was associated with poor melanoma-specific overall survival and poor disease-free survival. Cul4b expression was associated with Breslow categories, Clark level, and Ki67 expression. Univariate and multivariate analysis revealed that Cul4b is an independent prognosis risk factor of cutaneous melanoma. Downregulation of Cul4b inhibited the proliferation ability of melanoma cells and downregulated the expression of CDKN2A. These results suggest that Cul4b plays an essential role in cutaneous melanoma progression and may serve as a promising treatment target. [ABSTRACT FROM AUTHOR]

Resistance to temozolomide (TMZ), the first-line chemotherapeutic drug for glioblastoma (GBM) and anaplastic gliomas, is one of the most significant obstacles in clinical treatment. TMZ resistance is regulated by complex genetic and epigenetic networks. Understanding the mechanisms of TMZ resistance can help to identify novel drug targets and more effective therapies. CUL4B has been shown to be upregulated and promotes progression and chemoresistance in several cancer types. However, its regulatory effect and mechanisms on TMZ resistance have not been elucidated. The aim of this study was to decipher the role and mechanism of CUL4B in TMZ resistance. Western blot and public datasets analysis showed that CUL4B was upregulated in glioma specimens. CUL4B elevation positively correlated with advanced pathological stage, tumor recurrence, malignant molecular subtype and poor survival in glioma patients receiving TMZ treatment. CUL4B expression was correlated with TMZ resistance in GBM cell lines. Knocking down CUL4B restored TMZ sensitivity, while upregulation of CUL4B promoted TMZ resistance in GBM cells. By employing senescence β-galactosidase staining, quantitative reverse transcription PCR and Chromatin immunoprecipitation experiments, we found that CUL4B coordinated histone deacetylase (HDAC) to co-occupy the CDKN1A promoter and epigenetically silenced CDKN1A transcription, leading to attenuation of TMZ-induced senescence and rendering the GBM cells TMZ resistance. Collectively, our findings identify a novel mechanism by which GBM cells develop resistance to TMZ and suggest that CUL4B inhibition may be beneficial for overcoming resistance. [ABSTRACT FROM AUTHOR]

Cullins, critical members of the cullin-RING ubiquitin ligases (CRLs), are often aberrantly expressed in different cancers. However, the underlying mechanisms regarding aberrant expression of these cullins and the specific substrates of CRLs in different cancers are mostly unknown. Here, we demonstrate that overexpressed CUL4B in human osteosarcoma cells forms an E3 complex with DNA damage binding protein 1 (DDB1) and DDB1- and CUL4-associated factor 13 (DCAF13). In vitro and in vivo analyses indicated that the CRL4BDCAF13 E3 ligase specifically recognized the tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10) for degradation, and disruption of this E3 ligase resulted in PTEN accumulation. Further analyses indicated that miR-300 directly targeted the 3′ UTR of CUL4B, and DNA hypermethylation of a CpG island in the miR-300 promoter region contributed to the downregulation of miR-300. Interestingly, ectopic expression of miR-300 or treatment with 5-AZA-2′-deoxycytidine, a DNA methylation inhibitor, decreased the stability of CRL4BDCAF13 E3 ligase and reduced PTEN ubiquitination. By applying in vitro screening to identify small molecules that specifically inhibit CUL4B-DDB1 interaction, we found that TSC01131 could greatly inhibit osteosarcoma cell growth and could disrupt the stability of the CRL4BDCAF13 E3 ligase. Collectively, our findings shed new light on the molecular mechanism of CUL4B function and might also provide a new avenue for osteosarcoma therapy.

Detecting clinical grade CNV based on WES is being improved in the NGS era. [ABSTRACT FROM AUTHOR]

Background: Prostate cancer (PCa) is the second most common cancer among men, threatening men's health and life. Long noncoding RNA Zinc-finger E-box binding homeobox 1 antisense gene 1 (ZEB1-AS1) and Cullin 4B (CUL4B) were reported to be connected with the tumorigenesis of PCa. However, it is unclear whether ZEB1-AS1 regulates the expression of CUL4B in PCa. Materials and Methods: The levels of ZEB1-AS1 and CUL4B in PCa tissues and cells were evaluated by quantitative real-time polymerase chain reaction. Protein levels of CUL4B, p21, CyclinD1, matrix metalloprotease 9 (MMP9), E-cadherin, phosphorylated-phosphatidylinositol 3 kinase (p-PI3K), PI3K phosphorylated protein kinase B (p-AKT), AKT, p-mTOR and mammalian target of rapamycin (mTOR) in PCa tissues or cells were assessed by Western blot analysis. The proliferation, migration, and invasion abilities of PCa cells were determined with 3-(4, 5-dimethylthiazol-2-YI)-2,5-diphenyltetrazolium bromide (MTT) or transwell assay. The interaction between ZEB1-AS1 or CUL4B and microRNA-342-3p (miR-342-3p) was predicted using starBase v2.0 database and confirmed by the dual-luciferase reporter assay. Results: ZEB1-AS1 and CUL4B were upregulated and miR-342-3p was downregulated in PCa tissues and cells. Both ZEB1-AS1 and CUL4B inhibition constrained proliferation, migration, and invasion of PCa cells. Moreover, the elevation of CUL4B reversed the effects of ZEB1-AS1 silencing on the proliferation, migration, and invasion of PCa cells. Importantly, ZEB1-AS1 modulated CUL4B expression by sponging miR-342-3p in PCa cells. Besides, ZEB1-AS1 mediated PI3K/AKT/mTOR signal pathway by miR-342-3p/CUL4B axis in PCa cells. Conclusion: ZEB1-AS1 modulated PCa progression through mediating PI3K/AKT/mTOR signaling by miR-342-3p/CUL4B axis, providing a possible strategy for the treatment of PCa. [ABSTRACT FROM AUTHOR]

Background: Ovarian cancer is one of the most common malignant tumors in the female reproductive system with the highest mortality rate. Cul4B participates in the oncogenesis and progression of several malignant tumors. However, the role of Cul4B in ovarian cancer has not been studied. Results: High expression of intratumor Cul4B was associated with poor patient survival. Cul4B expression was associated with FIGO stage and Cul4B was independent risk factor of ovarian cancer disease-free survival and overall survival. In vitro studies revealed that overexpression of Cul4B promoted tumor proliferation while knockdown of Cul4B significantly inhibited the proliferation capacity of ovarian cancer cells. Mechanistically, Cul4B was found to promotes cell entering S phase from G0/G1 phase by regulating the expression of CDK2 and CyclinD1. Cul4B regulates the expression of CDK2 and CyclinD1 by repressing miR-372. Conclusions: The results revealed that high expression of Cul4B is associated with poor ovarian cancer prognosis and Cul4B may serve as a potential treating target for an adjuvant therapy. [ABSTRACT FROM AUTHOR]

Aim: Cullin 4B (CUL4B) is a member of the cullin ubiquitin-ligase family, which participates in proteolysis. Aberrant CUL4B expression has been shown in many malignancies. This study aimed to elucidate oncogenic role of CUL4B in gastric cancer (GC). Methods: CUL4B expression in GC tissues was examined by RT-PCR and immunohistochemistry. The proliferation, invasion and tumorigenicity of GC cells with CUL4B overexpression or knockdown were evaluated. Results: CUL4B expression significantly increased in GC tissues, and was correlated to UICC stage and differentiation of GC, as well as poor overall survival and disease-free survival. Both univariate and multivariate analysis identified CUL4B as an independent predictor for GC patient prognosis. In addition, CUL4B promoted GC cell proliferation and invasion in vitro and tumor formation in vivo. Conclusion: CUL4B is overexpressed to promote GC development and progression. CUL4B is a promising prognostic marker and therapeutic target for GC. [ABSTRACT FROM AUTHOR]

Inflammation is one of the major causes of intervertebral disc degeneration (IDD). Emerging evidence has revealed that increase in the levels of pro‐inflammatory cytokines, such as interleukin 6 (IL‐6) and tumor necrosis factor alpha (TNF‐α), can activate a variety of signaling pathways, eventually resulting in IDD. Here, we show that the two cullin family genes, CUL4A and CUL4B, but not other cullins, are specifically overexpressed in IDD samples compared with healthy controls, and the CUL4A and CUL4B levels are positively correlated with the severity of IDD. In vitro analyses in human osteoblast cells (hFOB1.19), nucleus pulposus cells (hNPCs), and annulus fibrosus cells (hAFCs) indicated that treatment with IL‐6 and TNF‐α can increase CUL4A and CUL4B levels. By performing a microRNA‐based microarray analysis, we found a set of microRNAs (miRNAs) that were differentially expressed in IDD samples compared with samples from healthy controls. Of these miRNAs, miR‐194‐5p, was significantly downregulated in IDD samples and could bind to the three prime untranslated regions (3′‐UTRs) of both CUL4A and CUL4B, thereby downregulating their expression. The in vitro overexpression or downregulation of miR‐194‐5p, with a miR‐194‐5p‐mimic or with anti‐miR‐194‐5p, can cause the repression or induction of both CUL4A and CUL4B, respectively. Interestingly, treatment with IL‐6 and TNF‐α inhibitors in primary hNPCs and hAFCs that were isolated from patients with IDD led to the downregulation of CUL4A and CUL4B. Together, these findings provide insight into how the inflammation‐dependent downregulation of miR‐194‐5p contributes to the pathogenesis of IDD, which may aid in the development of new therapeutic approaches for IDD by directly targeting miR‐194‐5p or CUL4A and CUL4B. [ABSTRACT FROM AUTHOR]

Lung cancer is the most frequent cancer type and is the leading cause of tumour‐associated deaths worldwide. Nuclear cap‐binding protein 1 (NCBP1) is necessary for capped RNA processing and intracellular localization. It has been reported that silencing of NCBP1 resulted in cell growth reduction in HeLa cells. Nevertheless, its clinical significance and underlying molecular mechanisms in non–small‐cell lung cancer remain unclear. In this study, we found that NCBP1 was significantly overexpressed in lung cancer tissues and several lung cancer cell lines. Through knockdown and overexpression experiments, we showed that NCBP1 promoted lung cancer cell growth, wound healing ability, migration and epithelial‐mesenchymal transition. Mechanistically, we found that cullin 4B (CUL4B) was a downstream target gene of NCBP1 in NSCLC. NCBP1 up‐regulated CUL4B expression via interaction with nuclear cap‐binding protein 3 (NCBP3). CUL4B silencing significantly reversed NCBP1‐induced tumorigenesis in vitro. Based on these findings, we propose a model involving the NCBP1‐NCBP3‐CUL4B oncoprotein axis, providing novel insight into how CUL4B is activated and contributes to LUAD progression. [ABSTRACT FROM AUTHOR]

Inflammation is well known as an important driver of the initiation of colitis‐associated cancer (CAC). Some cytokines, such as IL‐6 and TNF‐α can activate expression of the oncogene c‐Myc (MYC) and regulate its downstream effects. Cullin‐RING E3 Ligases (CRLs) are emerging as master regulators controlling tumorigenesis. Here, we demonstrate that two cullin genes, CUL4A and CUL4B, but not other members, are specifically overexpressed in CAC tumour samples and positively correlate with levels of the proinflammatory cytokines IL‐1β and IL‐6. In vitro experiments revealed that the transcription factor c‐Myc can specifically activate the expression of CUL4A and CUL4B by binding to a conserved site (CACGTG) located in their promoters. Additionally, we found that both CUL4A and CUL4B can form an E3 complex with DNA damage‐binding protein 1 (DDB1) and DDB1‐CUL4‐associated factor 4 (DCAF4). In vitro and in vivo ubiquitination analyses indicate that CRL4DCAF4 E3 ligase specifically directs degradation of ST7 (suppression of tumorigenicity 7). Overexpression of c‐Myc in human colon epithelial cells resulted in the accumulation of CUL4A, CUL4B and DCAF4, but degradation of ST7. In contrast, knockdown of c‐Myc, CUL4A or CUL4B in the colon adenocarcinoma cell line HT29 caused accumulation of ST7 and inhibition of cell proliferation, colony formation ability and in vivo tumour growth. Collectively, our results provide in vitro and in vivo evidence that c‐Myc regulates CRL4DCAF4 E3 ligase activity to mediate ubiquitination of ST7, whose presence is physiologically essential for CAC tumorigenesis. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Previous studies have revealed that CUL4B is overexpressed in various types of cancer and that its overexpression is related to the progression and metastasis of tumors. However, the biological functions of CUL4B in the progression of head and neck squamous cell carcinoma (HNSCC) are still not well understood. In the current study, we aimed to determine the changes in biological functions and molecular events that are related to CUL4B overexpression. Interestingly, our results showed that CUL4B is upregulated in HNSCC and that its upregulation is associated with poor survival and worse histological grade. Overexpression of CUL4B promoted cancer cell growth, invasion, and migration, as well as epithelial‐mesenchymal transition, whereas the loss of CUL4B abrogated these malignant phenotypes. Moreover, our mechanistic investigations suggest that the Wnt/β‐catenin signaling pathway was activated by CUL4B overexpression. Treatment with a Wnt/β‐catenin inhibitor decreased CUL4B‐induced migration and invasion, establishing a key role of Wnt/β‐catenin signaling in mediating the effects of CUL4B expression. Together, these results demonstrate a key contribution of CUL4B overexpression in the malignant behavior of HNSCC cells, at least in part through the stimulation of angiogenesis and the activation of the Wnt/β‐catenin signaling pathway.CUL4B upregulated in HNSCC, which relate to poor survival and worse histological grade. CUL4B promotes cancer cell growth, invasion, and migration. Wnt/β‐catenin signaling pathway involved in the action of CUL4B in HNSCC. [ABSTRACT FROM AUTHOR]

Background: The role of the histone ubiquitination-related gene in the cisplatin resistance of lung adenocarcinoma (LUAD) remains an intricate subject. Methods: We accessed transcriptome data of both wild type and cisplatin-resistant cells from the GSE108214 dataset, and garnered transcriptome and clinical data of LUAD patients from The Cancer Genome Atlas (TCGA) database. Utilizing the R software, we analyzed these public datasets in depth. Real-time Quantitative PCR (qPCR) was used to detect the RNA level of CUL4B. Effect of CUL4B on cell proliferation was evaluated using CCK8 and colony formation assay. Effect of CUL4B on cell invasion was evaluated using transwell assay. Cisplatin sensitivity was evaluated by calculating IC50. Results: Our analysis shed light on the significance of the histone ubiquitination-related gene, CUL4B, in relation to cisplatin resistance and the overall survival rates of LUAD patients. Notably, CUL4B was found to be overexpressed in both lung cancer tissues and cells. Meanwhile, in vitro experiments indicated can CUL4B significantly promote the proliferation, invasion and migration of lung cancer cells. Furthermore, suppressing CUL4B expression led to a noticeable reduction in the IC50 value of cisplatin in lung cancer cells. A deep dive into biological enrichment analysis revealed that among patients exhibiting high CUL4B expression, there was a pronounced activation of the G2M checkpoint and the PI3K/AKT/mTOR signaling pathways. Immune microenvironment analysis has revealed that patients with elevated CUL4B expression may exhibit increased infiltration of M2 macrophages, coupled with a reduced infiltration of CD8 + T cells and activated NK cells. Notably, we observed higher CUL4B expression among those who responded positively to immunotherapy. Conclusion: These findings underscore the significance of CUL4B in the resistance to cisplatin in lung cancer, highlighting its potential as a therapeutic target., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Yin, Zhang, Zeng, Chen, Guan, Ran and Du.)

OBJECTIVE: The functions of miRNA-708 for various diseases have been con- firmed. However, its roles in osteosarcoma are unclear. In this study, we aimed to explore the role of miRNA-708 in osteosarcoma. PATIENTS AND METHODS: Detection of the expression of miRNA-708 and CUL4B was used by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Cells were transfected with miRNA-708 mimics (mimics group) and miRNA negative control (NC group). Detection of cell growth curve at 24 h, 48 h, 72 h, and 96 h was made by cell counting kit-8 (CCK-8). Examination of the apoptosis rate was made by flow cytometry. The identification of the regulatory function was made by the luciferase reporter assay. The expression level of CUL4B was detected by Western blot. RESULTS: MiRNA-708 expression was reduced in the tumor cell lines. Compared with NC group, miRNA-708 expression was up-regulated by transfecting with mimics. Lower proliferation efficiency and higher cell apoptosis were showed in miRNA-708 mimics group relative to NC group. MiRNA-708 could regulate the expression of CUL4B by binding to its 3'UTR area. Furthermore, lower miRNA-708 and higher CUL4B were expressed in tumor tissues. MiRNA-708 expression was lower in tissues with IIB-III stage than that in IA-IIA stage. CONCLUSIONS: MiRNA-708/CUL4B axis contributes into cell proliferation and apoptosis of osteosarcoma. [ABSTRACT FROM AUTHOR]

The E3 ubiquitin ligase HUWE1/Mule/ARF-BP1 plays an important role in diverse biological processes including DNA damage repair and apoptosis. Our previous study has shown that in response to DNA damage HUWE1 was downregulated in CUL4B-mediated ubiquitination and subsequent proteasomal degradation, and CUL4B-mediated regulation of HUWE1 was important for cell survival upon DNA damage. CUL4B is a core component of the CUL4B Ring ligase complexes containing ROC1, DDB1 and a DDB1-Cullin Associated Factors (DCAFs), the latter of which are DDB1-binding WD40 adaptors critical for substrate recognition and recruitment. However, the identity of DCAF in CRL4B that mediates degradation of HUWE1 remains elusive. Here we report that RBBP7 is the DCAF in the CRL4B complex bridging the DDB1-CUL4B-ROC1 to HUWE1. Loading of HUWE1 to the E3 ubiquitin ligase complex resulted in its polyubiquitination, and consequently its proteasome mediated degradation. Overexpression of RBBP7 promoted HUWE1 protein degradation, while depletion of RBBP7 stabilized HUWE1, and hence accelerated the degradation of MCL-1 and BRCA1, two substrates of HUWE1 that are critical in apoptosis and DNA damage repair. Taken together, these data reveal CRL4B RBBP7 is the E3 ligase responsible for the proteasomal degradation of HUWE1, and further provide a potential strategy for cancer therapy by targeting HUWE1 and the CUL4B E3 ligase complex. [ABSTRACT FROM AUTHOR]