RESUMO
A mesenchymal tumor phenotype associates with immunotherapy resistance, although the mechanism is unclear. Here, we identified FBXO7 as a maintenance regulator of mesenchymal and immune evasion phenotypes of cancer cells. FBXO7 bound and stabilized SIX1 co-transcriptional regulator EYA2, stimulating mesenchymal gene expression and suppressing IFNα/ß, chemokines CXCL9/10, and antigen presentation machinery, driven by AXL extracellular ligand GAS6. Ubiquitin ligase SCFFBXW7 antagonized this pathway by promoting EYA2 degradation. Targeting EYA2 Tyr phosphatase activity decreased mesenchymal phenotypes and enhanced cancer cell immunogenicity, resulting in attenuated tumor growth and metastasis, increased infiltration of cytotoxic T and NK cells, and enhanced anti-PD-1 therapy response in mouse tumor models. FBXO7 expression correlated with mesenchymal and immune-suppressive signatures in patients with cancer. An FBXO7-immune gene signature predicted immunotherapy responses. Collectively, the FBXO7/EYA2-SCFFBXW7 axis maintains mesenchymal and immune evasion phenotypes of cancer cells, providing rationale to evaluate FBXO7/EYA2 inhibitors in combination with immune-based therapies to enhance onco-immunotherapy responses.
Assuntos
Proteínas F-Box , Proteína 7 com Repetições F-Box-WD , Neoplasias , Animais , Linhagem Celular Tumoral , Proteínas F-Box/genética , Proteínas F-Box/metabolismo , Proteína 7 com Repetições F-Box-WD/genética , Proteínas de Homeodomínio/genética , Humanos , Evasão da Resposta Imune , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Camundongos , Neoplasias/genética , Proteínas Nucleares/metabolismo , Fenótipo , Proteínas Tirosina Fosfatases/genética , Ubiquitina/metabolismoRESUMO
FBXW7 is an E3 ubiquitin ligase that targets proteins for proteasome-mediated degradation and is mutated in various cancer types. Here, we use CRISPR base editors to introduce different FBXW7 hotspot mutations in human colon organoids. Functionally, FBXW7 mutation reduces EGF dependency of organoid growth by ~10,000-fold. Combined transcriptomic and proteomic analyses revealed increased EGFR protein stability in FBXW7 mutants. Two distinct phosphodegron motifs reside in the cytoplasmic tail of EGFR. Mutations in these phosphodegron motifs occur in human cancer. CRISPR-mediated disruption of the phosphodegron motif at T693 reduced EGFR degradation and EGF growth factor dependency. FBXW7 mutant organoids showed reduced sensitivity to EGFR-MAPK inhibitors. These observations were further strengthened in CRC-derived organoid lines and validated in a cohort of patients treated with panitumumab. Our data imply that FBXW7 mutations reduce EGF dependency by disabling EGFR turnover.
Assuntos
Proteínas F-Box , Neoplasias , Humanos , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Fator de Crescimento Epidérmico/genética , Fator de Crescimento Epidérmico/farmacologia , Fator de Crescimento Epidérmico/metabolismo , Proteômica , Receptores ErbB/genética , Receptores ErbB/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/metabolismo , Proteínas F-Box/genéticaRESUMO
Neurodevelopmental disorders are highly heterogenous conditions resulting from abnormalities of brain architecture and/or function. FBXW7 (F-box and WD-repeat-domain-containing 7), a recognized developmental regulator and tumor suppressor, has been shown to regulate cell-cycle progression and cell growth and survival by targeting substrates including CYCLIN E1/2 and NOTCH for degradation via the ubiquitin proteasome system. We used a genotype-first approach and global data-sharing platforms to identify 35 individuals harboring de novo and inherited FBXW7 germline monoallelic chromosomal deletions and nonsense, frameshift, splice-site, and missense variants associated with a neurodevelopmental syndrome. The FBXW7 neurodevelopmental syndrome is distinguished by global developmental delay, borderline to severe intellectual disability, hypotonia, and gastrointestinal issues. Brain imaging detailed variable underlying structural abnormalities affecting the cerebellum, corpus collosum, and white matter. A crystal-structure model of FBXW7 predicted that missense variants were clustered at the substrate-binding surface of the WD40 domain and that these might reduce FBXW7 substrate binding affinity. Expression of recombinant FBXW7 missense variants in cultured cells demonstrated impaired CYCLIN E1 and CYCLIN E2 turnover. Pan-neuronal knockdown of the Drosophila ortholog, archipelago, impaired learning and neuronal function. Collectively, the data presented herein provide compelling evidence of an F-Box protein-related, phenotypically variable neurodevelopmental disorder associated with monoallelic variants in FBXW7.
Assuntos
Proteína 7 com Repetições F-Box-WD , Transtornos do Neurodesenvolvimento , Ubiquitinação , Proteína 7 com Repetições F-Box-WD/química , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Células Germinativas , Mutação em Linhagem Germinativa , Humanos , Transtornos do Neurodesenvolvimento/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Human T-cell leukemia virus type 1 (HTLV-I) is the etiological agent of adult T-cell leukemia (ATL). Mutational analysis has demonstrated that the tumor suppressor, F-box and WD repeat domain containing 7 (FBXW7/FBW7/CDC4), is mutated in primary ATL patients. However, even in the absence of genetic mutations, FBXW7 substrates are stabilized in ATL cells, suggesting additional mechanisms can prevent FBXW7 functions. Here, we report that the viral oncoprotein Tax represses FBXW7 activity, resulting in the stabilization of activated Notch intracellular domain, c-MYC, Cyclin E, and myeloid cell leukemia sequence 1 (BCL2-related) (Mcl-1). Mechanistically, we demonstrate that Tax directly binds to FBXW7 in the nucleus, effectively outcompeting other targets for binding to FBXW7, resulting in decreased ubiquitination and degradation of FBXW7 substrates. In support of the nuclear role of Tax, a non-degradable form of the nuclear factor kappa B subunit 2 (NFκB2/p100) was found to delocalize Tax to the cytoplasm, thereby preventing Tax interactions with FBXW7 and Tax-mediated inhibition of FBXW7. Finally, we characterize a Tax mutant that is unable to interact with FBXW7, unable to block FBXW7 tumor suppressor functions, and unable to effectively transform fibroblasts. These results demonstrate that HTLV-I Tax can inhibit FBXW7 functions without genetic mutations to promote an oncogenic state. These results suggest that Tax-mediated inhibition of FBXW7 is likely critical during the early stages of the cellular transformation process. IMPORTANCE: F-box and WD repeat domain containing 7 (FBXW7), a critical tumor suppressor of human cancers, is frequently mutated or epigenetically suppressed. Loss of FBXW7 functions is associated with stabilization and increased expression of oncogenic factors such as Cyclin E, c-Myc, Mcl-1, mTOR, Jun, and Notch. In this study, we demonstrate that the human retrovirus human T-cell leukemia virus type 1 oncoprotein Tax directly interacts with FBXW7, effectively outcompeting other targets for binding to FBXW7, resulting in decreased ubiquitination and degradation of FBXW7 cellular substrates. We further demonstrate that a Tax mutant unable to interact with and inactivate FBXW7 loses its ability to transform primary fibroblasts. Collectively, our results describe a novel mechanism used by a human tumor virus to promote cellular transformation.
Assuntos
Proteínas de Ciclo Celular , Proteínas F-Box , Proteína 7 com Repetições F-Box-WD , Produtos do Gene tax , Vírus Linfotrópico T Tipo 1 Humano , Ubiquitina-Proteína Ligases , Proteína 7 com Repetições F-Box-WD/metabolismo , Proteína 7 com Repetições F-Box-WD/genética , Humanos , Vírus Linfotrópico T Tipo 1 Humano/genética , Vírus Linfotrópico T Tipo 1 Humano/metabolismo , Produtos do Gene tax/metabolismo , Produtos do Gene tax/genética , Proteínas F-Box/metabolismo , Proteínas F-Box/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Ligação ProteicaRESUMO
Chemotherapy resistance to colon cancer is an unavoidable obstacle in the clinical management of the disease. Clitocine, an adenosine analog, played a significant role in the chemosensitivity of human colon cancer cells by promoting MCL-1 protein degradation. However, the detailed mechanism remains to be further elucidated. We found that clitocine up-regulates the expression of FBXW7, a ubiquitin ligase involved in the MCL-1 degradation. Transcriptome sequencing analysis revealed that clitocine significantly inhibits the cAMP and ERK downstream signaling pathways in colon cancer cells, thereby enhancing FBXW7 expression and subsequently promoting the ubiquitination degradation of MCL-1 protein. We verified that clitocine regulated intracellular cAMP levels by competitive binding with the adenosine receptor A2B. Molecular docking assay also verified the binding relationship. By decreasing intracellular cAMP levels, clitocine blocks the activation of downstream signaling pathways, which ultimately enhances the drug sensitivity of colon cancer cells through increased FBXW7 expression due to the inhibition of its promoter DNA methylation. Both knock-out of adenosine receptor A2B and Br-cAMP treatment can effectively attenuate the function of clitocine in vitro and in vivo. This study clarified that clitocine enhanced the drug sensitivity of colon cancer cells by promoting FBXW7-mediated MCL-1 degradation via inhibiting the A2B/cAMP/ERK axis, providing further knowledge of the clinical application for clitocine.
RESUMO
Premature ovarian insufficiency (POI) is one of the important causes of female infertility. Yet the aetiology for POI is still elusive. FBXW7 (F-box with 7 tandem WD) is one of the important components of the Skp1-Cullin1-F-box (SCF) E3 ubiquitin ligase. FBXW7 can regulate cell growth, survival and pluripotency through mediating ubiquitylation and degradation of target proteins via triggering the ubiquitin-proteasome system, and is associated with tumorigenesis, haematopoiesis and testis development. However, evidence establishing the function of FBXW7 in ovary is still lacking. Here, we showed that FBXW7 protein level was significantly decreased in the ovaries of the cisplatin-induced POI mouse model. We further showed that mice with oocyte-specific deletion of Fbxw7 demonstrated POI, characterized with folliculogenic defects, early depletion of follicle reserve, disordered hormonal secretion, ovarian dysfunction and female infertility. Impaired oocyte-GCs communication, manifested as down-regulation of connexin 37, may contribute to follicular development failure in the Fbxw7-mutant mice. Furthermore, single-cell RNA sequencing and in situ hybridization results indicated an accumulation of Clu and Ccl2 transcripts, which may alter follicle microenvironment deleterious to oocyte development and accelerate POI. Our results establish the important role of Fbxw7 in folliculogenesis and ovarian function, and might provide valuable information for understanding POI and female infertility.
Assuntos
Proteína 7 com Repetições F-Box-WD , Oócitos , Folículo Ovariano , Insuficiência Ovariana Primária , Animais , Feminino , Insuficiência Ovariana Primária/genética , Insuficiência Ovariana Primária/metabolismo , Insuficiência Ovariana Primária/patologia , Proteína 7 com Repetições F-Box-WD/metabolismo , Proteína 7 com Repetições F-Box-WD/genética , Oócitos/metabolismo , Camundongos , Folículo Ovariano/metabolismo , Folículo Ovariano/crescimento & desenvolvimento , Folículo Ovariano/patologia , Modelos Animais de Doenças , Deleção de Genes , Camundongos Knockout , Infertilidade Feminina/genética , Infertilidade Feminina/metabolismo , Infertilidade Feminina/patologia , Cisplatino/efeitos adversosRESUMO
Increasing evidence shows the oncogenic function of FAM83D in human cancer, but how FAM83D exerts its oncogenic function remains largely unclear. Here, we investigated the importance of FAM83D/FBXW7 interaction in breast cancer (BC). We systematically mapped the FBXW7-binding sites on FAM83D through a comprehensive mutational analysis together with co-immunoprecipitation assay. Mutations at the FBXW7-binding sites on FAM83D led to that FAM83D lost its capability to promote the ubiquitination and proteasomal degradation of FBXW7; cell proliferation, migration, and invasion in vitro; and tumor growth and metastasis in vivo, indicating that the FBXW7-binding sites on FAM83D are essential for its oncogenic functions. A meta-evaluation of FAM83D revealed that the prognostic impact of FAM83D was independent on molecular subtypes. The higher expression of FAM83D has poorer prognosis. Moreover, high expression of FAM83D confers resistance to chemotherapy in BCs, which is experimentally validated in vitro. We conclude that identification of FBXW7-binding sites on FAM83D not only reveals the importance for FAM83D oncogenic function, but also provides valuable insights for drug target.
Assuntos
Neoplasias da Mama , Proteínas de Ciclo Celular , Humanos , Feminino , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Prognóstico , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismoRESUMO
BACKGROUND: Cancer stem cells (CSCs) are a small population of cells in tumor tissues that can drive tumor initiation and promote tumor progression. A small number of previous studies indirectly mentioned the role of F-box and WD repeat domain-containing 7 (FBXW7) as a tumor suppressor in Triple-negative breast cancer (TNBC). However, few studies have focused on the function of FBXW7 in cancer stemness in TNBC and the related mechanism. METHODS: We detected FBXW7 by immunohistochemistry (IHC) in 80 TNBC patients. FBXW7 knockdown and overexpression in MD-MBA-231 and HCC1937 cell models were constructed. The effect of FBXW7 on malignant phenotype and stemness was assessed by colony assays, flow cytometry, transwell assays, western blot, and sphere formation assays. Immunoprecipitation-Mass Spectrometry (IP-MS) and ubiquitination experiments were used to find and verify potential downstream substrate proteins of FBXW7. Animal experiments were constructed to examine the effect of FBXW7 on tumorigenic potential and cancer stemness of TNBC cells in vivo. RESULTS: The results showed that FBXW7 was expressed at low levels in TNBC tissues and positively correlated with prognosis of TNBC patients. In vitro, FBXW7 significantly inhibited colony formation, cell cycle progression, cell migration, EMT process, cancer stemness and promotes apoptosis. Further experiments confirmed that chromodomain-helicase-DNA-binding protein 4 (CHD4) is a novel downstream target of FBXW7 and is downregulated by FBXW7 via proteasomal degradation. Moreover, CHD4 could promote the nuclear translocation of ß-catenin and reverse the inhibitory effect of FBXW7 on ß-catenin, and ultimately activate the Wnt/ß-catenin pathway. Rescue experiments confirmed that the FBXW7-CHD4-Wnt/ß-catenin axis was involved in regulating the maintenance of CSC in TNBC cells. In animal experiments, FBXW7 reduced CSC marker expression and suppressed TNBC cell tumorigenesis in vivo. CONCLUSIONS: Taken together, these results highlight that FBXW7 degrades CHD4 protein through ubiquitination, thereby blocking the activation of the Wnt/ß-catenin pathway to inhibit the stemness of TNBC cells. Thus, targeting FBXW7 may be a promising strategy for therapeutic intervention against TNBC.
Assuntos
Neoplasias de Mama Triplo Negativas , Animais , Humanos , beta Catenina , Carcinogênese , Transformação Celular Neoplásica , Proteína 7 com Repetições F-Box-WD/genética , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase , Neoplasias de Mama Triplo Negativas/genéticaRESUMO
Emerging research has demonstrated that genomic alterations disrupting topologically associated domains (TADs) and chromatin interactions underlie the pathogenic mechanisms of specific copy number variants (CNVs) in neurodevelopmental disorders. We report two patients with a de novo deletion and a duplication in chromosome 4q31, potentially causing FBX-related neurodevelopmental syndrome by affecting the regulatory region of FBXW7. High-throughput chromosome conformation capture (Hi-C) analysis using available capture data in neural progenitor cells revealed the rewiring of the TAD boundary close to FBXW7. Both patients exhibited facial dysmorphisms, cardiac and limb abnormalities, and neurodevelopmental delays, showing significant clinical overlap with previously reported FBXW7-related features. We also included an additional 10 patients with CNVs in the 4q31 region from the literature and the DECIPHER database for Hi-C analysis, which confirmed that disruption of the regulatory region of FBXW7 likely contributes to the developmental defects observed in these patients.
Assuntos
Cromossomos Humanos Par 4 , Variações do Número de Cópias de DNA , Proteína 7 com Repetições F-Box-WD , Transtornos do Neurodesenvolvimento , Humanos , Proteína 7 com Repetições F-Box-WD/genética , Variações do Número de Cópias de DNA/genética , Masculino , Feminino , Transtornos do Neurodesenvolvimento/genética , Cromossomos Humanos Par 4/genética , Sequências Reguladoras de Ácido Nucleico/genética , Pré-Escolar , Deficiências do Desenvolvimento/genética , Deficiências do Desenvolvimento/patologia , Predisposição Genética para Doença , Criança , LactenteRESUMO
Somatic variants in the NOTCH pathway regulator FBXW7 are frequently seen in a variety of malignancies. Heterozygous loss-of-function germline variants in FBXW7 have recently been described as causative for a neurodevelopmental syndrome. Independently, FBXW7 was also considered as a susceptibility gene for Wilms tumor due to a few observations of heterozygous germline variants in patients with Wilms tumor. Whether the same FBXW7 variants are implicated in both, neurodevelopmental delay and Wilms tumor formation, remained unclear. By clinical testing, we now observed a patient with neurodevelopmental delay due to a de novo constitutional mosaic FBXW7 splice site pathogenic variant who developed Wilms tumor. In the tumor, we identified a second hit frameshift variant in FBXW7. Immunohistochemical staining was consistent with mosaic loss of FBXW7 protein expression in the tumor. Our data support the role of constitutional FBXW7 pathogenic variants in both, neurodevelopmental disorder and the etiology of Wilms tumor. Therefore, Wilms tumor screening should be considered in individuals with constitutional or germline pathogenic variants in FBXW7 and associated neurodevelopmental syndrome.
Assuntos
Proteína 7 com Repetições F-Box-WD , Predisposição Genética para Doença , Tumor de Wilms , Humanos , Masculino , Proteína 7 com Repetições F-Box-WD/genética , Mutação da Fase de Leitura/genética , Mutação em Linhagem Germinativa/genética , Neoplasias Renais/genética , Neoplasias Renais/patologia , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/patologia , Tumor de Wilms/genética , Tumor de Wilms/patologia , CriançaRESUMO
FBXW7, which encodes a substrate-specific receptor of an SCF E3 ligase complex, is a frequently mutated human tumor suppressor gene known to regulate the post-translational stability of various proteins involved in cellular proliferation. Here, using genome-wide CRISPR screens, we report a novel synthetic lethal genetic interaction between FBXW7 and CCNL1 and describe CCNL1 as a new substrate of the SCF-FBXW7 E3 ligase. Further analysis showed that the CCNL1-CDK11 complex is critical at the G2-M phase of the cell cycle since defective CCNL1 accumulation, resulting from FBXW7 mutation, leads to shorter mitotic time. Cells harboring FBXW7 loss-of-function mutations are hypersensitive to treatment with a CDK11 inhibitor, highlighting a genetic vulnerability that could be leveraged for cancer treatment.
Assuntos
Ciclinas , Proteína 7 com Repetições F-Box-WD , Ubiquitina-Proteína Ligases , Humanos , Proteína 7 com Repetições F-Box-WD/genética , Mutação , Ubiquitina-Proteína Ligases/genética , Ciclinas/metabolismo , UbiquitinaçãoRESUMO
BACKGROUND: Imatinib contributes to improving prognosis of high-risk or unresectable gastrointestinal stromal tumors (GISTs). As therapeutic efficacy is limited by imatinib resistance and toxicity, the exploration of predictive markers of imatinib therapeutic efficacy that enables patients to utilize more effective therapeutic strategies remains urgent. METHODS: The correlation between FBXW7 and imatinib resistance via FBXW7-MCL1 axis was evaluated in vitro and in vivo experiments. The significance of FBXW7 as a predictor of imatinib treatment efficacy was examined in 140 high-risk patients with GISTs. RESULTS: The ability of FBXW7 to predict therapeutic efficacy of adjuvant imatinib in high-risk GIST patients was determined through 5-year recurrence-free survival (RFS) rates analysis and multivariate analysis. FBXW7 affects imatinib sensitivity by regulating apoptosis in GIST-T1 cells. FBXW7 targets MCL1 to regulate apoptosis. MCL1 involves in the regulation of imatinib sensitivity through inhibiting apoptosis in GIST-T1 cells. FBXW7 regulates imatinib sensitivity by down-regulating MCL1 to enhance imatinib-induced apoptosis in vitro. FBXW7 regulates imatinib sensitivity of GIST cells by targeting MCL1 to predict efficacy of imatinib treatment in vivo. CONCLUSIONS: FBXW7 regulates imatinib sensitivity by inhibiting MCL1 to enhance imatinib-induced apoptosis in GIST, and predicts efficacy of imatinib treatment in high-risk GIST patients treated with imatinib.
Assuntos
Antineoplásicos , Proteína 7 com Repetições F-Box-WD , Neoplasias Gastrointestinais , Tumores do Estroma Gastrointestinal , Mesilato de Imatinib , Neoplasias Gástricas , Humanos , Antineoplásicos/uso terapêutico , Proteína 7 com Repetições F-Box-WD/metabolismo , Neoplasias Gastrointestinais/tratamento farmacológico , Neoplasias Gastrointestinais/patologia , Tumores do Estroma Gastrointestinal/tratamento farmacológico , Tumores do Estroma Gastrointestinal/patologia , Mesilato de Imatinib/uso terapêutico , Proteína de Sequência 1 de Leucemia de Células Mieloides/uso terapêutico , Neoplasias Gástricas/tratamento farmacológicoRESUMO
Faithful chromosome segregation requires correct attachment of kinetochores with the spindle microtubules. Erroneously-attached kinetochores recruit proteins to activate Spindle assembly checkpoint (SAC), which senses the errors and signals cells to delay anaphase progression for error correction. Temporal control of the levels of SAC activating-proteins is critical for checkpoint activation and silencing, but its mechanism is not fully understood. Here, we show that E3 ubiquitin ligase, SCF-FBXW7 targets BubR1 for ubiquitin-mediated degradation and thereby controls SAC in human cells. Depletion of FBXW7 results in prolonged metaphase arrest with increased stabilization of BubR1 at kinetochores. Similar kinetochore stabilization is also observed for BubR1-interacting protein, CENP-E. FBXW7 induced ubiquitination of both BubR1 and the BubR1-interacting kinetochore-targeting domain of CENP-E, but CENP-E domain degradation is dependent on BubR1. Interestingly, Cdk1 inhibition disrupts FBXW7-mediated BubR1 targeting and further, phospho-resistant mutation of Cdk1-targeted phosphorylation site, Thr 620 impairs BubR1-FBXW7 interaction and FBXW7-mediated BubR1 ubiquitination, supporting its role as a phosphodegron for FBXW7. The results demonstrate SCF-FBXW7 as a key regulator of spindle assembly checkpoint that controls stability of BubR1 and its associated CENP-E at kinetochores. They also support that upstream Cdk1 specific BubR1 phosphorylation signals the ligase to activate the process.
Assuntos
Proteínas de Ciclo Celular , Proteínas Serina-Treonina Quinases , Humanos , Proteínas de Ciclo Celular/metabolismo , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Células HeLa , Cinetocoros/metabolismo , Mitose , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Fuso Acromático/metabolismo , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismoRESUMO
The Notch pathway is a key cancer driver and is important in tumor progression. Early research suggested that Notch activity was highly dependent on the expression of the intracellular cleaved domain of Notch-1 (NICD). However, recent insights into Notch signaling reveal the presence of Notch pathway signatures, which may vary depending on different cancer types and tumor microenvironments. Herein, we perform a comprehensive investigation of the Notch signaling pathway in adult T-cell leukemia (ATL) primary patient samples. Using gene arrays, we demonstrate that the Notch pathway is constitutively activated in ATL patient samples. Furthermore, the activation of Notch in ATL cells remains elevated irrespective of the presence of activating mutations in Notch itself or its repressor, FBXW7, and that ATL cells are dependent upon Notch-1 expression for proliferation and survival. We demonstrate that ATL cells exhibit the expression of pivotal Notch-related genes, including notch-1, hes1, c-myc, H19, and hes4, thereby defining a critical Notch signature associated with ATL disease. Finally, we demonstrate that lncRNA H19 is highly expressed in ATL patient samples and ATL cells and contributes to Notch signaling activation. Collectively, our results shed further light on the Notch pathway in ATL leukemia and reveal new therapeutic approaches to inhibit Notch activation in ATL cells.
Assuntos
Leucemia-Linfoma de Células T do Adulto , MicroRNAs , RNA Longo não Codificante , Transdução de Sinais , Humanos , Leucemia-Linfoma de Células T do Adulto/genética , Leucemia-Linfoma de Células T do Adulto/metabolismo , Leucemia-Linfoma de Células T do Adulto/patologia , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Linhagem Celular Tumoral , Receptor Notch1/metabolismo , Receptor Notch1/genética , Regulação Leucêmica da Expressão Gênica , Receptores Notch/metabolismo , Receptores Notch/genética , Proliferação de Células/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Proteína 7 com Repetições F-Box-WD/genética , Regulação Neoplásica da Expressão Gênica , AdultoRESUMO
The tumor suppressor gene F-box and WD repeat domain-containing (FBXW) 7 reduces cancer stemness properties by promoting the protein degradation of pluripotent stem cell markers. We recently demonstrated the transcriptional repression of FBXW7 by the three-dimensional (3D) spheroid formation of several cancer cells. In the present study, we found that the transcriptional activity of FBXW7 was promoted by the inhibition of the Ca2+-activated K+ channel, KCa1.1, in a 3D spheroid model of human prostate cancer LNCaP cells through the Akt-Nrf2 signaling pathway. The transcriptional activity of FBXW7 was reduced by the siRNA-mediated inhibition of the CCAAT-enhancer-binding protein C/EBP δ (CEBPD) after the transfection of miR223 mimics in the LNCaP spheroid model, suggesting the transcriptional regulation of FBXW7 through the Akt-Nrf2-CEBPD-miR223 transcriptional axis in the LNCaP spheroid model. Furthermore, the KCa1.1 inhibition-induced activation of FBXW7 reduced (1) KCa1.1 activity and protein levels in the plasma membrane and (2) the protein level of the cancer stem cell (CSC) markers, c-Myc, which is a molecule degraded by FBXW7, in the LNCaP spheroid model, indicating that KCa1.1 inhibition-induced FBXW7 activation suppressed CSC conversion in KCa1.1-positive cancer cells.
Assuntos
Proteína 7 com Repetições F-Box-WD , Regulação Neoplásica da Expressão Gênica , Fator 2 Relacionado a NF-E2 , Neoplasias da Próstata , Transdução de Sinais , Esferoides Celulares , Humanos , Proteína 7 com Repetições F-Box-WD/metabolismo , Proteína 7 com Repetições F-Box-WD/genética , Masculino , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Esferoides Celulares/metabolismo , Linhagem Celular Tumoral , Regulação para Cima , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/genética , Canais de Potássio Ativados por Cálcio de Condutância Intermediária/antagonistas & inibidores , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismoRESUMO
During prolonged mitotic arrest induced by antimicrotubule drugs, cell fate decision is determined by two alternative pathways, one leading to cell death and the other inducing premature escape from mitosis by mitotic slippage. FBWX7, a member of the F-box family of proteins and substrate-targeting subunit of the SKP1-CUL1-F-Box E3 ubiquitin ligase complex, promotes mitotic cell death and prevents mitotic slippage, but molecular details underlying these roles for FBWX7 are unclear. In this study, we report that WDR5 (WD-repeat containing protein 5), a component of the mixed lineage leukemia complex of histone 3 lysine 4 methyltransferases, is a substrate of FBXW7. We determined by coimmunoprecipitation experiments and in vitro binding assays that WDR5 interacts with FBXW7 in vivo and in vitro. SKP1-CUL1-F-Box-FBXW7 mediates ubiquitination of WDR5 and targets it for proteasomal degradation. Furthermore, we find that WDR5 depletion counteracts FBXW7 loss of function by reducing mitotic slippage and polyploidization. In conclusion, our data elucidate a new mechanism in mitotic cell fate regulation, which might contribute to prevent chemotherapy resistance in patients after antimicrotubule drug treatment.
Assuntos
Proteína 7 com Repetições F-Box-WD , Histona-Lisina N-Metiltransferase , Peptídeos e Proteínas de Sinalização Intracelular , Humanos , Proteínas de Ciclo Celular/metabolismo , Proteína 7 com Repetições F-Box-WD/metabolismo , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lisina/metabolismo , Proteínas Ligases SKP Culina F-Box/genética , Proteínas Ligases SKP Culina F-Box/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
Osteoporosis influences life quality among elder people. Osteoblast dysfunction could cause the occurrence of osteoporosis. LncRNA XIST are involved in the progression of osteoporosis. However, the correlation between IRF-1 and XIST in osteogenic differentiation remains unclear. In the study, Clinical samples were collected for the analysis of XIST level. mRNA and protein levels were detected by RT-qPCR and western blot, respectively. H&E staining was performed to observe the histological changes in mice. Alizarin Red Staining was applied to assess the calcium deposits in hBMSCs. Meanwhile, the relation among XIST, miR-450b and FBXW7 was investigated by dual luciferase assay and ChIP. In vivo model was constructed to assess the impact of XIST in osteoporosis. XIST was found to be upregulated in osteoporosis, and XIST overexpression could inhibit the osteogenic differentiation in hBMSCs. IRF-1 could transcriptionally inhibit the expression of XIST, and XIST could inhibit osteogenic differentiation through binding with miR-450b in hBMSCs. In addition, miR-450b significantly promoted the osteogenic differentiation in hBMSCs via targeting FBXW7. Furthermore, XIST knockdown could inhibit the symptom of osteoporosis in vivo. IRF-1 promoted the osteogenic differentiation via mediation of lncRNA XIST/miR-450b/FBXW7 axis, and this finding might shed novel insights on exploring new ideas against osteoporosis.
Assuntos
Células-Tronco Mesenquimais , MicroRNAs , Osteoporose , RNA Longo não Codificante , Animais , Camundongos , Apoptose , Diferenciação Celular/genética , Células Cultivadas , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Células-Tronco Mesenquimais/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Osteogênese/genética , Osteoporose/genética , Osteoporose/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismoRESUMO
Our recent study suggests that FBXW7 loss of function plays a critical function in esophageal cancer. However, the mechanism of FBXW7 in promoting esophageal cancer is still unclear. Here, we explored the interaction protein of FBXW7 by screening of GST-pulldown and LC-MS/MS analysis in esophageal squamous cell carcinoma (ESCC) and identified ANXA2 as a potential target of FBXW7. FBXW7 loss of function could restore the expression of ANXA2 and promote the malignant biological characteristics of ESCC cells in vitro. Up-regulation of ANXA2 enhances the ERK pathway in ESCC. Furthermore, the 23rd tyrosine residue of ANXA2, phosphorylated by SRC, was regarded as playing important roles in the FBXW7-related degradation system. In clinical samples, we found that ANXA2 had high expression in ESCC tissues. High ANXA2 was associated with poor tumor staging. More importantly, we designed a combination regimen including SCH779284, a clinical ERK inhibitor against the phosphorylation of EKR and siRNA targeting ANXA2 by intratumor injection, and it produced potent inhibitory effects on the growth of xenograft tumors in vivo. In conclusion, this study provided evidence that FBXW7 loss of function could promote esophageal cancer through ANXA2 overexpression, and this novel regulation pathway may be used as an efficient target for ESCC treatment.
Assuntos
Anexina A2 , Carcinoma de Células Escamosas , Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Humanos , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/metabolismo , Neoplasias Esofágicas/patologia , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Carcinoma de Células Escamosas/patologia , Fosforilação , Cromatografia Líquida , Espectrometria de Massas em Tandem , Linhagem Celular Tumoral , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Anexina A2/metabolismoRESUMO
Activation of a canonical EGFR-Ras-Raf-ERK cascade initiates patterning of multipotent vulval precursor cells (VPCs) of Caenorhabditis elegans We have previously shown that this pathway includes a negative-feedback component in which MPK-1/ERK activity targets the upstream kinase LIN-45/Raf for degradation by the SEL-10/FBXW7 E3 ubiquitin ligase. This regulation requires a Cdc4 phosphodegron (CPD) in LIN-45 that is conserved in BRAF. Here, we identify and characterize the minimal degron that encompasses the CPD and is sufficient for SEL-10-mediated, MPK-1-dependent protein degradation. A targeted screen of conserved protein kinase-encoding genes yielded gsk-3 (an ortholog of human GSK3B) and cdk-2 (a CDK2-related kinase) as required for LIN-45 degron-mediated turnover. Genetic analysis revealed that LIN-45 degradation is blocked at the second larval stage due to cell cycle quiescence, and that relief of this block during the third larval stage relies on activation of CDKs. Additionally, activation of MPK-1 provides spatial pattern to LIN-45 degradation but does not bypass the requirement for gsk-3 and cdk-2 This analysis supports a model whereby MPK-1/ERK, GSK-3/GSK3 and CDK-2/CDK2, along with SEL-10/FBXW7, constitute a regulatory network that exerts spatial and temporal control of LIN-45/Raf degradation during VPC patterning.
Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/crescimento & desenvolvimento , Quinase 3 da Glicogênio Sintase/genética , Vulva/crescimento & desenvolvimento , Quinases raf/genética , Animais , Caenorhabditis elegans/genética , Proteínas de Ciclo Celular/genética , Diferenciação Celular/genética , Retroalimentação Fisiológica , Feminino , Regulação da Expressão Gênica no Desenvolvimento/genética , Fosfotransferases/genética , Proteólise , Transdução de Sinais/genética , Ubiquitina-Proteína Ligases , Vulva/metabolismoRESUMO
HIV-associated neurocognitive disorders (HAND) remain pervasive even with increased efficacy/use of antiretroviral therapies. Opioid use/abuse among HIV + individuals is documented to exacerbate CNS deficits. White matter (WM) alterations, including myelin pallor, and volume/structural alterations detected by diffusion tensor imaging are common observations in HIV + individuals, and studies in non-human primates suggest that WM may harbor virus. Using transgenic mice that express the HIV-1 Tat protein, we examined in vivo effects of 2-6 weeks of Tat and morphine exposure on WM using genomic and biochemical methods. RNA sequencing of striatal tissue at 2 weeks revealed robust changes in mRNAs associated with oligodendrocyte precursor populations and myelin integrity, including those for transferrin, the atypical oligodendrocyte marker N-myc downstream regulated 1 (Ndrg1), and myelin regulatory factor (Myrf/Mrf), an oligodendrocyte-specific transcription factor with a significant role in oligodendrocyte differentiation/maturation. Western blots conducted after 6-weeks exposure in 3 brain regions (striatum, corpus callosum, pre-frontal cortex) revealed regional differences in the effect of Tat and morphine on Myrf levels, and on levels of myelin basic protein (MBP), whose transcription is regulated by Myrf. Responses included individual and interactive effects. Although baseline and post-treatment levels of Myrf and MBP differed between brain regions, post-treatment MBP levels in striatum and pre-frontal cortex were compatible with changes in Myrf activity. Additionally, the Myrf regulatory ubiquitin ligase Fbxw7 was identified as a novel target in our model. These results suggest that Myrf and Fbxw7 contribute to altered myelin gene regulation in HIV.