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1.
Breast Cancer Res ; 26(1): 37, 2024 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-38454442

RESUMO

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/metabolismo
2.
Cell Death Dis ; 15(3): 212, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38485719

RESUMO

During the maturation of hematopoietic stem/progenitor cells (HSPCs) to fully differentiated mature B lymphocytes, developing lymphocytes may undergo malignant transformation and produce B-cell lymphomas. Emerging evidence shows that through the endothelial-hematopoietic transition, specialized endothelial cells called the hemogenic endothelium can differentiate into HSPCs. However, the contribution of genetic defects in hemogenic endothelial cells to B-cell lymphomagenesis has not yet been investigated. Here, we report that mice with endothelial cell-specific deletion of Fbw7 spontaneously developed diffuse large B-cell lymphoma (DLBCL) following Bcl6 accumulation. Using lineage tracing, we showed that B-cell lymphomas in Fbw7 knockout mice were hemogenic endothelium-derived. Mechanistically, we found that FBW7 directly interacted with Bcl6 and promoted its proteasomal degradation. FBW7 expression levels are inversely correlated with BCL6 expression. Additionally, pharmacological disruption of Bcl6 abolished Fbw7 deletion-induced B-cell lymphomagenesis. We conclude that selective deletion of E3 ubiquitin ligase FBW7 in VE-cadherin positive endothelial cells instigates diffuse large B-cell lymphoma via upregulation of BCL6 stability. In addition, the mice with endothelial cell-specific deletion of Fbw7 provide a valuable preclinical platform for in vivo development and evaluation of novel therapeutic interventions for the treatment of DLBCL.


Assuntos
Antígenos CD , Caderinas , Linfoma Difuso de Grandes Células B , Ubiquitina-Proteína Ligases , Animais , Camundongos , Células Endoteliais/metabolismo , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/metabolismo , Camundongos Knockout , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
3.
Proc Natl Acad Sci U S A ; 121(12): e2309902121, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38483988

RESUMO

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/genética
4.
Sci Signal ; 17(826): eadh4475, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38442201

RESUMO

The translation elongation factor eEF1A promotes protein synthesis. Its methylation by METTL13 increases its activity, supporting tumor growth. However, in some cancers, a high abundance of eEF1A isoforms is associated with a good prognosis. Here, we found that eEF1A2 exhibited oncogenic or tumor-suppressor functions depending on its interaction with METTL13 or the phosphatase PTEN, respectively. METTL13 and PTEN competed for interaction with eEF1A2 in the same structural domain. PTEN-bound eEF1A2 promoted the ubiquitination and degradation of the mitosis-promoting Aurora kinase A in the S and G2 phases of the cell cycle. eEF1A2 bridged the interactions between the SKP1-CUL1-FBXW7 (SCF) ubiquitin ligase complex, the kinase GSK3ß, and Aurora-A, thereby facilitating the phosphorylation of Aurora-A in a degron site that was recognized by FBXW7. Genetic ablation of Eef1a2 or Pten in mice resulted in a greater abundance of Aurora-A and increased cell cycling in mammary tumors, which was corroborated in breast cancer tissues from patients. Reactivating this pathway using fimepinostat, which relieves inhibitory signaling directed at PTEN and increases FBXW7 expression, combined with inhibiting Aurora-A with alisertib, suppressed breast cancer cell proliferation in culture and tumor growth in vivo. The findings demonstrate a therapeutically exploitable, tumor-suppressive role for eEF1A2 in breast cancer.


Assuntos
Aurora Quinase A , Neoplasias da Mama , Neoplasias Mamárias Animais , PTEN Fosfo-Hidrolase , Fator 1 de Elongação de Peptídeos , Animais , Feminino , Humanos , Camundongos , Aurora Quinase A/genética , Aurora Quinase A/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proteína 7 com Repetições F-Box-WD/genética , Glicogênio Sintase Quinase 3 beta , Neoplasias Mamárias Animais/genética , Neoplasias Mamárias Animais/metabolismo , Neoplasias Mamárias Animais/patologia , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Fator 1 de Elongação de Peptídeos/genética , Fator 1 de Elongação de Peptídeos/metabolismo
5.
J Hazard Mater ; 468: 133704, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38364577

RESUMO

Our previous study revealed that 1-nitropyrene (1-NP) exposure evoked pulmonary fibrosis in mice. However, the exact mechanism remained elusive. We found that 1-NP induced telomere damage and cellular senescence in mice lungs, and two alveolar epithelial cells lines. 1-NP downregulated telomere repeat binding factor 2 (TRF2), and upregulated FBXW7. Mechanistically, 1-NP-caused TRF2 ubiquitination and proteasomal degradation depended on E3 ubiquitin ligase activity of FBXW7. Moreover, 1-NP upregulated FBXW7 m6A modification via an ALKBH5-YTHDF1-dependent manner. Further analysis suggested 1-NP promoted ALKBH5 SUMOylation and subsequent proteasomal degradation. Additionally, 1-NP evoked mitochondrial reactive oxygen species (mtROS) overproduction. Mito-TEMPO, a mitochondrial-targeted antioxidant, mitigated 1-NP-caused mtROS overproduction, ALKBH5 SUMOylation, FBXW7 m6A modification, TRF2 degradation, cellular senescence, and pulmonary fibrosis. Taken together, mtROS-initiated ALKBH5 SUMOylation and subsequent FBXW7 m6A modification is indispensable for TRF2 degradation and cellular senescence in alveolar epithelial cells during 1-NP-induced pulmonary fibrosis. Our study provides target intervention measures towards 1-NP-evoked pulmonary fibrosis.


Assuntos
Adenina/análogos & derivados , Fibrose Pulmonar , Pirenos , Sumoilação , Animais , Camundongos , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Células Epiteliais Alveolares/metabolismo , Fibrose Pulmonar/induzido quimicamente
6.
Cell Mol Life Sci ; 81(1): 87, 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38349431

RESUMO

The existence of cancer stem cells is widely acknowledged as the underlying cause for the challenging curability and high relapse rates observed in various tumor types, including non-small cell lung cancer (NSCLC). Despite extensive research on numerous therapeutic targets for NSCLC treatment, the strategies to effectively combat NSCLC stemness and achieve a definitive cure are still not well defined. The primary objective of this study was to examine the underlying mechanism through which Fructose-1,6-bisphosphatase 1 (FBP1), a gluconeogenic enzyme, functions as a tumor suppressor to regulate the stemness of NSCLC. Herein, we showed that overexpression of FBP1 led to a decrease in the proportion of CD133-positive cells, weakened tumorigenicity, and decreased expression of stemness factors. FBP1 inhibited the activation of Notch signaling, while it had no impact on the transcription level of Notch 1 intracellular domain (NICD1). Instead, FBP1 interacted with NICD1 and the E3 ubiquitin ligase FBXW7 to facilitate the degradation of NICD1 through the ubiquitin-proteasome pathway, which is independent of the metabolic enzymatic activity of FBP1. The aforementioned studies suggest that targeting the FBP1-FBXW7-NICD1 axis holds promise as a therapeutic approach for addressing the challenges of NSCLC recurrence and drug resistance.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/genética , Proteína 7 com Repetições F-Box-WD/genética , Frutose , Neoplasias Pulmonares/genética , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
7.
J Exp Clin Cancer Res ; 43(1): 34, 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38281999

RESUMO

BACKGROUND: The development of radioresistance seriously hinders the efficacy of radiotherapy in lung cancer. However, the underlying mechanisms by which radioresistance occurs are still incompletely understood. The N6-Methyladenosine (m6A) modification of RNA is involved in cancer progression, but its role in lung cancer radioresistance remains elusive. This study aimed to identify m6A regulators involved in lung cancer radiosensitivity and further explore the underlying mechanisms to identify therapeutic targets to overcome lung cancer radioresistance. METHODS: Bioinformatic mining was used to identify the m6A regulator IGF2BP2 involved in lung cancer radiosensitivity. Transcriptome sequencing was used to explore the downstream factors. Clonogenic survival assays, neutral comet assays, Rad51 foci formation assays, and Annexin V/propidium iodide assays were used to determine the significance of FBW7/IGF2BP2/SLC7A5 axis in lung cancer radioresistance. Chromatin immunoprecipitation (ChIP)-qPCR analyses, RNA immunoprecipitation (RIP) and methylated RNA immunoprecipitation (MeRIP)-qPCR analyses, RNA pull-down analyses, co-immunoprecipitation analyses, and ubiquitination assays were used to determine the feedback loop between IGF2BP2 and SLC7A5 and the regulatory effect of FBW7/GSK3ß on IGF2BP2. Mice models and tissue microarrays were used to verify the effects in vivo. RESULTS: We identified IGF2BP2, an m6A "reader", that is overexpressed in lung cancer and facilitates radioresistance. We showed that inhibition of IGF2BP2 impairs radioresistance in lung cancer both in vitro and in vivo. Furthermore, we found that IGF2BP2 enhances the stability and translation of SLC7A5 mRNA through m6A modification, resulting in enhanced SLC7A5-mediated transport of methionine to produce S-adenosylmethionine. This feeds back upon the IGF2BP2 promoter region by further increasing the trimethyl modification at lysine 4 of histone H3 (H3K4me3) level to upregulate IGF2BP2 expression. We demonstrated that this positive feedback loop between IGF2BP2 and SLC7A5 promotes lung cancer radioresistance through the AKT/mTOR pathway. Moreover, we found that the ubiquitin ligase FBW7 functions with GSK3ß kinase to recognize and degrade IGF2BP2. CONCLUSIONS: Collectively, our study revealed that the m6A "reader" IGF2BP2 promotes lung cancer radioresistance by forming a positive feedback loop with SLC7A5, suggesting that IGF2BP2 may be a potential therapeutic target to control radioresistance in lung cancer.


Assuntos
Proteína 7 com Repetições F-Box-WD , Transportador 1 de Aminoácidos Neutros Grandes , Neoplasias Pulmonares , Proteínas de Ligação a RNA , Animais , Camundongos , Linhagem Celular Tumoral , Glicogênio Sintase Quinase 3 beta/genética , Transportador 1 de Aminoácidos Neutros Grandes/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/radioterapia , RNA , Proteína 7 com Repetições F-Box-WD/genética , Proteínas de Ligação a RNA/genética , Tolerância a Radiação
8.
Gene ; 901: 148181, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38244948

RESUMO

FBXW7, belonging to the F-Box protein family, is considered a candidate cancer susceptibility gene. Our findings indicate that single nucleotide polymorphisms (SNPs) in the FBXW7 gene are linked to cancer risk, strengthening FBXW7's role in the pathogenesis of colorectal cancer. Our case-control study comprised of 450 patients diagnosed with colorectal cancer (CRC) and an equal number of 450 healthy subjects. FBXW7 SNPs rs2255137C>T and rs6842544C>T were genotyped using PCR-Restriction Fragment Length Polymorphism (PCR-RFLP) and Single-Stranded Conformation Polymorphism (SSCP) techniques and further cross-checked by direct sequencing. Linkage disequilibrium and haplotype analyses of these SNPs were also assessed. The in-silico approach was used to reveal the functional analysis between the nonsynonymous variation (rs6842544) and CRC followed by its validation at the protein level by western blotting and reverse transcription-PCR. A significant association of colorectal cancer was detected with rs6842544 SNP. However, there was no association between FBXW7 rs2255137 polymorphism and CRC. The homozygous individuals carrying the C variant in FBXW7 rs6842544 showed a slightly higher risk for colorectal cancer (OR = 1.590, 95%CI = 0.39 âˆ¼ 2.89, p = 0.011). The haplotype CC identified in this study seemed to be associated with good prognosis (OR = 1.22, 95% CI = 1.00 âˆ¼ 1.47, p = 0.0013) whereas the TT haplotype was found to reduce the CRC risk (OR = 0.642, 95%CI = 0.48 âˆ¼ 0.84, p = 0.039). In-silico prediction proposed that the variant R133G is responsible for the lower expression of FBXW7. Additionally, the expression profiling of FBXW7 nonsynonymous SNP was significantly lower in primary CRC tissues than in the paired non-cancerous tissues at protein and mRNA levels. The study indicates that the FBXW7 rs6842544 is associated with the risk of development of CRC and could serve as a molecular biological marker to screen high-risk groups for CRC.


Assuntos
Neoplasias Colorretais , Proteína 7 com Repetições F-Box-WD , Predisposição Genética para Doença , Humanos , Estudos de Casos e Controles , Neoplasias Colorretais/patologia , Proteína 7 com Repetições F-Box-WD/genética , Genótipo , Polimorfismo de Nucleotídeo Único
9.
J Transl Med ; 22(1): 99, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38268032

RESUMO

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/genética
10.
Mol Oncol ; 18(3): 562-579, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38279565

RESUMO

Notch signaling is aberrantly activated in approximately 30% of hepatocellular carcinoma (HCC), significantly contributing to tumorigenesis and disease progression. Expression of the major Notch receptor, NOTCH1, is upregulated in HCC cells and correlates with advanced disease stages, although the molecular mechanisms underlying its overexpression remain unclear. Here, we report that expression of the intracellular domain of NOTCH1 (NICD1) is upregulated in HCC cells due to antagonism between the E3-ubiquitin ligase F-box/WD repeat-containing protein 7 (FBXW7) and the large scaffold protein abnormal spindle-like microcephaly-associated protein (ASPM) isoform 1 (ASPM-i1). Mechanistically, FBXW7-mediated polyubiquitination and the subsequent proteasomal degradation of NICD1 are hampered by the interaction of NICD1 with ASPM-i1, thereby stabilizing NICD1 and rendering HCC cells responsive to stimulation by Notch ligands. Consistently, downregulating ASPM-i1 expression reduced the protein abundance of NICD1 but not its FBXW7-binding-deficient mutant. Reinforcing the oncogenic function of this regulatory module, the forced expression of NICD1 significantly restored the tumorigenic potential of ASPM-i1-deficient HCC cells. Echoing these findings, NICD1 was found to be strongly co-expressed with ASPM-i1 in cancer cells in human HCC tissues (P < 0.001). In conclusion, our study identifies a novel Notch signaling regulatory mechanism mediated by protein-protein interaction between NICD1, FBXW7, and ASPM-i1 in HCC cells, representing a targetable vulnerability in human HCC.


Assuntos
Carcinoma Hepatocelular , Proteínas F-Box , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proteínas F-Box/genética , Proteínas F-Box/metabolismo , Proteína 7 com Repetições F-Box-WD/genética , Neoplasias Hepáticas/patologia , Proteínas do Tecido Nervoso/metabolismo , Receptor Notch1/genética , Receptor Notch1/metabolismo
11.
Cell Death Dis ; 15(1): 34, 2024 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-38212325

RESUMO

Intrahepatic cholangiocarcinoma (ICC) is the second most common malignancy among primary liver cancers, with an increasing overall incidence and poor prognosis. The intertumoral and intratumoral heterogeneity of ICC makes it difficult to find efficient drug therapies. Therefore, it is essential to identify tumor suppressor genes and oncogenes that induce ICC formation and progression. Here, we performed CRISPR/Cas9-mediated genome-wide screening in a liver-specific Smad4/Pten knockout mouse model (Smad4co/co;Ptenco/co;Alb-Cre, abbreviated as SPC), which normally generates ICC after 6 months, and detected that mutations in Trp53, Fbxw7, Inppl1, Tgfbr2, or Cul3 markedly accelerated ICC formation. To illustrate the potential mechanisms, we conducted transcriptome sequencing and found that multiple receptor tyrosine kinases were activated, which mainly upregulated the PI3K pathway to induce cell proliferation. Remarkably, the Cul3 mutation stimulated cancer progression mainly by altering the immune microenvironment, whereas other mutations promoted the cell cycle. Moreover, Fbxw7, Inppl1, Tgfbr2, and Trp53 also affect inflammatory responses, apelin signaling, mitotic spindles, ribosome biogenesis, and nucleocytoplasmic transport pathways, respectively. We further examined FDA-approved drugs for the treatment of liver cancer and performed high-throughput drug screening of the gene-mutant organoids. Different drug responses and promising drug therapies, including chemotherapy and targeted drugs, have been discovered for ICC.


Assuntos
Neoplasias dos Ductos Biliares , Colangiocarcinoma , Camundongos , Animais , Receptor do Fator de Crescimento Transformador beta Tipo II/metabolismo , Proteína 7 com Repetições F-Box-WD/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Colangiocarcinoma/tratamento farmacológico , Colangiocarcinoma/genética , Colangiocarcinoma/metabolismo , Mutação/genética , Transdução de Sinais , Ductos Biliares Intra-Hepáticos/patologia , Neoplasias dos Ductos Biliares/tratamento farmacológico , Neoplasias dos Ductos Biliares/genética , Neoplasias dos Ductos Biliares/metabolismo , Microambiente Tumoral
12.
Mol Oncol ; 18(2): 369-385, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37866880

RESUMO

The F-box and WD repeat domain containing 7 (FBXW7) tumour suppressor gene encodes a substrate-recognition subunit of Skp, cullin, F-box (SCF)-containing complexes. The tumour-suppressive role of FBXW7 is ascribed to its ability to drive ubiquitination and degradation of oncoproteins. Despite this molecular understanding, therapeutic approaches that target defective FBXW7 have not been identified. Using genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 screens, focussed RNA-interference screens and whole and phospho-proteome mass spectrometry profiling in multiple FBXW7 wild-type and defective isogenic cell lines, we identified a number of FBXW7 synthetic lethal targets, including proteins involved in the response to replication fork stress and proteins involved in replication origin firing, such as cell division cycle 7-related protein kinase (CDC7) and its substrate, DNA replication complex GINS protein SLD5 (GINS4). The CDC7 synthetic lethal effect was confirmed using small-molecule inhibitors. Mechanistically, FBXW7/CDC7 synthetic lethality is dependent upon the replication factor telomere-associated protein RIF1 (RIF1), with RIF1 silencing reversing the FBXW7-selective effects of CDC7 inhibition. The delineation of FBXW7 synthetic lethal effects we describe here could serve as the starting point for subsequent drug discovery and/or development in this area.


Assuntos
Proteínas de Ciclo Celular , Neoplasias , Humanos , Proteína 7 com Repetições F-Box-WD/genética , Linhagem Celular Tumoral , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Ubiquitinação , Interferência de RNA , Domínios Proteicos , Ubiquitina-Proteína Ligases/metabolismo , Neoplasias/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Cromossômicas não Histona/genética
13.
Gastric Cancer ; 27(2): 235-247, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38142463

RESUMO

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 farmacológico
14.
Oral Dis ; 29(8): 3259-3267, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38055341

RESUMO

BACKGROUND: Oral cancer is associated with high risk of morbidity and mortality. However, effective treatment for oral cancer is urgently required in clinics. In this study, we aimed to determine whether F-box/WD repeat-containing protein 7 (FBXW7), an essential tumor suppressor gene, can regulate autophagy and improve the prognosis in oral squamous cell carcinoma (OSCC). METHODS: mRNA levels of FBXW7 and myeloid cell leukemia 1 (MCL-1) in OSCC tissues and adjacent normal tissues were measured by qRT-PCR. FBXW7 and MCL-1 were overexpressed in OSCC cell line using lentivirus containing FBXW7 and MCL-1, respectively. Protein expression was determined by Western blot. RESULTS: The mRNA and protein levels of FBXW7 were decreased in patients with OSCC, whereas the mRNA and protein levels of MCL-1 were increased. Moreover, the mRNA coding for autophagy proteins was reduced in patients with OSCC. Additionally, it was found that overexpression of FBXW7 significantly reduced MCL-1 expression and upregulated autophagy-related proteins, including Beclin1, autophagy related 7, and microtubule-associated protein light chain 3. CONCLUSION: Our results suggest that FBXW7 affects autophagy through MCL1 in OSCC.


Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Humanos , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Carcinoma de Células Escamosas/patologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Linhagem Celular Tumoral , Neoplasias Bucais/genética , Neoplasias Bucais/patologia , Autofagia/genética , Neoplasias de Cabeça e Pescoço/genética , RNA Mensageiro , Proliferação de Células , Regulação Neoplásica da Expressão Gênica
15.
Nat Commun ; 14(1): 6982, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37914694

RESUMO

Nonalcoholic steatohepatitis (NASH) is epidemiologically associated with obesity and diabetes and can lead to liver cirrhosis and hepatocellular carcinoma if left untreated. The intricate signaling pathways that orchestrate hepatocyte energy metabolism and cellular stress, intrahepatic cell crosstalk, as well as interplay between peripheral tissues remain elusive and are crucial for the development of anti-NASH therapies. Herein, we reveal E3 ligase FBXW7 as a key factor regulating hepatic catabolism, stress responses, systemic energy homeostasis, and NASH pathogenesis with attenuated FBXW7 expression as a feature of advanced NASH. Multiomics and pharmacological intervention showed that FBXW7 loss-of-function in hepatocytes disrupts a metabolic transcriptional axis conjointly controlled by the nutrient-sensing nuclear receptors ERRα and PPARα, resulting in suppression of fatty acid oxidation, elevated ER stress, apoptosis, immune infiltration, fibrogenesis, and ultimately NASH progression in male mice. These results provide the foundation for developing alternative strategies co-targeting ERRα and PPARα for the treatment of NASH.


Assuntos
Neoplasias Hepáticas , Hepatopatia Gordurosa não Alcoólica , Animais , Masculino , Camundongos , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Hepatócitos/metabolismo , Homeostase , Fígado/metabolismo , Neoplasias Hepáticas/metabolismo , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/metabolismo , Nutrientes , PPAR alfa/genética , PPAR alfa/metabolismo , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo
16.
Cancer Res Commun ; 3(12): 2596-2607, 2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38032106

RESUMO

FBXW7 is a commonly mutated tumor suppressor gene that functions to regulate numerous oncogenes involved in cell-cycle regulation. Genome-wide CRISPR fitness screens identified a signature of DNA repair and DNA damage response genes as required for the growth of FBXW7-knockout cells. Guided by these findings, we show that FBXW7-mutant cells have high levels of replication stress, which results in a genotype-specific vulnerability to inhibition of the ATR signaling pathway, as these mutant cells become heavily reliant on a robust S-G2 checkpoint. ATR inhibition induces an accelerated S-phase, leading to mitotic catastrophe and cell death caused by the high replication stress present in FBXW7-/- cells. In addition, we provide evidence in cell and organoid studies, and mining of publicly available high-throughput drug screening efforts, that this genotype-specific vulnerability extends to multiple types of cancer, providing a rational means of identifying responsive patients for targeted therapy. SIGNIFICANCE: We have elucidated the synthetic lethal interactions between FBXW7 mutation and DNA damage response genes, and highlighted the potential of ATR inhibitors as targeted therapies for cancers harboring FBXW7 alterations.


Assuntos
Reparo do DNA , Neoplasias , Humanos , Proteína 7 com Repetições F-Box-WD/genética , Proteínas Mutadas de Ataxia Telangiectasia/genética , Mutação , Neoplasias/genética , Morte Celular
17.
Neoplasma ; 70(6): 733-746, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38014700

RESUMO

F-box and WD repeat domain containing 7 (FBXW7) is an aboriginal and high-frequency mutant gene associated with esophageal squamous cell carcinoma (ESCC). This study was designed to determine the clinical value and molecular mechanisms of FBXW7 in the development of ESCC. The clinical significance of FBXW7 was analyzed in ESCC from TCGA data. The effects of FBXW7 on proliferation, colony formation, migration and invasion, angiogenesis, and apoptosis were tested in ESCC cells. PCR-array, sphere formation assay, and quantitative real-time polymerase chain reaction (qPCR) were used to explore the mechanism of FBXW7. FBXW7 was a significantly mutated gene in ESCC. It was an independent and potential predictor for survival in ESCC patients. In addition, FBXW7 overexpression significantly inhibited ESCC cell proliferation, migration, invasion, angiogenesis, and promoted cell apoptosis. PCR array revealed that FBXW7 overexpression leads to a significant change of gene expressions associated with angiogenesis, cell senescence, and DNA damage and repair. Sphere formation assay and qPCR showed FBXW7 was associated with ESCC stem cell formation. Our results suggest that FBXW7 may act as a tumor suppressor by repressing cancer stem cell formation and regulating tumor angiogenesis, cell senescence, DNA damage, and repair in ESCC.


Assuntos
Carcinoma de Células Escamosas , Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , MicroRNAs , Humanos , Carcinoma de Células Escamosas do Esôfago/genética , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Carcinoma de Células Escamosas/genética , Neoplasias Esofágicas/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Movimento Celular/genética , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética
18.
Cell Mol Life Sci ; 80(12): 374, 2023 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-38008853

RESUMO

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/metabolismo
19.
Cancer Res Commun ; 3(11): 2244-2255, 2023 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-37902422

RESUMO

Women of African descent have the highest breast cancer mortality in the United States and are more likely than women from other population groups to develop an aggressive disease. It remains uncertain to what extent breast cancer in Africa is reminiscent of breast cancer in African American or European American patients. Here, we performed whole-exome sequencing of genomic DNA from 191 breast tumor and non-cancerous adjacent tissue pairs obtained from 97 African American, 69 European American, 2 Asian American, and 23 Kenyan patients. Our analysis of the sequencing data revealed an elevated tumor mutational burden in both Kenyan and African American patients, when compared with European American patients. TP53 mutations were most prevalent, particularly in African American patients, followed by PIK3CA mutations, which showed similar frequencies in European American, African American, and the Kenyan patients. Mutations targeting TBX3 were confined to European Americans and those targeting the FBXW7 tumor suppressor to African American patients whereas mutations in the ARID1A gene that are known to confer resistance to endocrine therapy were distinctively enriched among Kenyan patients. A Kyoto Encyclopedia of Genes and Genomes pathway analysis could link FBXW7 mutations to an increased mitochondrial oxidative phosphorylation capacity in tumors carrying these mutations. Finally, Catalogue of Somatic Mutations in Cancer (COSMIC) mutational signatures in tumors correlated with the occurrence of driver mutations, immune cell profiles, and neighborhood deprivation with associations ranging from being mostly modest to occasionally robust. To conclude, we found mutational profiles that were different between these patient groups. The differences concentrated among genes with low mutation frequencies in breast cancer. SIGNIFICANCE: The study describes differences in tumor mutational profiles between African American, European American, and Kenyan breast cancer patients. It also investigates how these profiles may relate to the tumor immune environment and the neighborhood environment in which the patients had residence. Finally, it describes an overrepresentation of ARID1A gene mutations in breast tumors of the Kenyan patients.


Assuntos
Negro ou Afro-Americano , Neoplasias da Mama , Feminino , Humanos , Negro ou Afro-Americano/genética , Neoplasias da Mama/genética , Proteína 7 com Repetições F-Box-WD/genética , Quênia , Mutação , Estados Unidos , Brancos/genética , População Negra/genética , Asiático/genética
20.
J Immunol ; 211(11): 1701-1713, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37843504

RESUMO

Dendritic cells (DCs), a driver of psoriasis pathogenesis, produce IL-23 and trigger IL-23/IL-17 cytokine axis activation. However, the mechanisms regulating IL-23 induction remain unclear. In the current study, we found that mice with E3 ligase FBXW7 deficiency in DCs show reduced skin inflammation correlated with the reduction of IL-23/IL-17 axis cytokines in the imiquimod-induced psoriasis model. Fbxw7 deficiency results in decreased production of IL-23 in DCs. FBXW7 interacts with the lysine N-methyltransferase suppressor of variegation 39 homolog 2 (SUV39H2), which catalyzes the trimethylation of histone H3 Lys9 (H3K9) during transcription regulation. FBXW7 mediates the ubiquitination and degradation of SUV39H2, thus decreasing H3K9m3 deposition on the Il23a promoter. The Suv39h2 knockout mice displayed exacerbated skin inflammation with the IL-23/IL-17 axis overactivating in the psoriasis model. Taken together, our results indicate that FBXW7 increases IL-23 expression in DCs by degrading SUV39H2, thereby aggravating psoriasis-like inflammation. Inhibition of FBXW7 or the FBXW7/SUV39H2/IL-23 axis may represent a novel therapeutic approach to psoriasis.


Assuntos
Dermatite , Psoríase , Animais , Camundongos , Células Dendríticas/metabolismo , Dermatite/patologia , Modelos Animais de Doenças , Epigênese Genética , Proteína 7 com Repetições F-Box-WD/genética , Proteína 7 com Repetições F-Box-WD/metabolismo , Inflamação/metabolismo , Interleucina-17/metabolismo , Interleucina-23/metabolismo , Psoríase/patologia , Pele/patologia , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo
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