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1.
Cancer Lett ; 468: 27-40, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31604115

RESUMO

Patients with recurrent nasopharyngeal carcinoma (NPC) have more co-existing distant metastasis than those of no-recurrence and are more likely to suffer distant metastasis after re-irradiation than patients with newly diagnosed NPC. However, the relationship between radioresistance and distant metastasis and the mechanisms involved in radioresistance-associated metastasis are still unclear. In this study, we proved that C-C motif chemokine ligand 2 (CCL2) expression was significantly elevated in HONE1-IR cells and recurrent NPC tumour. Inhibition of CCL2 enhanced sensitivity to radiotherapy in NPC cells. Moreover, autocrine CCL2 promoted NPC cell adaptive radioresistance, metastasis and epithelial-mesenchymal transition. Additionally, p53 activated CCL2 transcription. High CCL2 expression was highly associated with poorer locoregional recurrence free survival, progression free survival and overall survival in patients with newly diagnosed NPC. Notably, high CCL2 expression was an independent prognostic factor for distant metastasis free survival in recurrent NPC patients. Our results provide insights into the autocrine signalling mechanisms of CCL2 and suggest that inhibition of autocrine CCL2 may be a candidate treatment strategy for management of radioresistant NPC.

2.
Cancer Res ; 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31484669

RESUMO

The genetic events occuring in recurrent nasopharyngeal carcinoma (rNPC) are poorly understood. Here, we performed whole-genome and whole-exome sequencing in 55 rNPC and 44 primarily diagnosed NPC (pNPC) patients; with 7 patients having paired rNPC and pNPC samples. Previously published pNPC exome data were integrated for analysis. rNPC and pNPC tissues had similar mutational burdens, however, the number of clonal mutations was increased in rNPC samples. TP53 and three NF-κB pathway components (TRAF3, CYLD and NFKBIA) were significantly mutated in both pNPC and rNPC. Notably, mutations in TRAF3, CYLD and NFKBIA were all clonal in rNPC, however, 55.6-57.9% of them were clonal in pNPC. In general, the number of clonal mutations in NF-κB pathway-associated genes was significantly higher in rNPC than in pNPC. The NF-κB mutational clonality was selected and/or enriched during NPC recurrence. The amount of NF-κB translocated to the nucleus in samples with clonal NF-κB mutants was significantly higher than that in samples with subclonal NF-κB mutants. Moreover, the nuclear abundance of NF-κB protein was significantly greater in pNPC samples with local regional relapse than in those without relapse. Further, high nuclear NF-κB levels were an independent negative prognostic marker for locoregional relapse-free survival in pNPC. Lastly, inhibition of NF-κB enhanced both radiosensitivity and chemosensitivity in vitro and in vivo. In conclusion, NF-κB pathway activation by clonal mutations plays an important role in promoting the recurrence of NPC. Moreover, nuclear accumulation of NF-κB is a prominent biomarker for predicting locoregional relapse-free survival.

3.
J Control Release ; 310: 11-21, 2019 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-31400382

RESUMO

Integrin α6 emerges to be a diagnostic biomarker for hepatocellular carcinoma (HCC). Here, we translated our previously identified integrin α6 targeted peptide RWY into a positron emission tomography (PET) tracer 18F-RWY for the detection of HCC lesions in following four HCC mouse models including subcutaneous, orthotopic, genetically engineered and chemical induced HCC mice. 18F-RWY produced high PET signals in liver tumor tissues that were reduced by blocking studies using nonradiolabeled RWY peptide. We compared the integrin α6 targeted PET tracer 18F-RWY with the integrin αvß3-targeted PET tracer 18F-3PRGD2 and the clinical PET tracer 18F-FDG in chemical induced HCC mice. Among 12 HCC identified by enhanced magnetic resonance imaging (MRI) with hepatocellular specific gadoxetate disodium Gd-EOB-DTPA, the sensitivities of 18F-RWY, 18F-3PRGD2 and 18F-FDG were approximately 92%, 73% and 50% while the tumor-to-liver ratios were 4.36 ±â€¯1.41, 1.97 ±â€¯0.43 and 1.63 ±â€¯0.23 respectively. Additionally, PET imaging with the integrin α6 targeted 18F-RWY enabled to visualize small HCC lesions with diameters approximately 0.2 cm that was hard to be distinguished from surround hepatic vascular by enhanced MRI with Gd-EOB-DTPA. These findings potentiate the use of integrin α6 targeted PET tracer 18F-RWY for the detection of HCC.

4.
Oncogene ; 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31462708

RESUMO

Soft tissue sarcoma (STS) is a highly malignant tumor with limited targeted therapies. A novel anaplastic lymphoma kinase (ALK) transcript, ALKATI, was identified recently and could be targeted by ALK inhibitors in melanoma. However, the clinical and functional role of aberrant ALKATI expression in STS remains unknown. Here we demonstrate that as a new ALK transcript, ALKATI is frequently found in STS. ALKATI expression correlates with a lower probability of progression-free survival in STS patients. Compared with the other ALK isoforms, ALKATI expresses not only in the cytoplasm, but also in the nucleus of sarcoma cells. Functionally, overexpression of ALKATI promoted cancer stem cell (CSC)-like properties in sarcoma cells by promoting sphere formation and upregulating the expression of stem cell markers. Moreover, the ALK inhibitors not only suppressed the oncogenic functions of ALKATI but also attenuated ALKATI-induced CSC-like properties by reducing the expression of stem cell markers such as c-Myc, ABCG2, BMI1, and OCT4 both in vitro and in vivo. Furthermore, ALKATI interacted with c-Myc and increased the binding of c-Myc to the ABCG2 promoter, resulting in the induction of stem cell-like properties. Together, these findings indicate that ALKATI may be a potential prognostic marker and therapeutic target for STS patients harboring such ALK aberrations.

6.
Cell Signal ; 63: 109363, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31344439

RESUMO

Platelet counts have been reported to be closely related to distant metastasis of many malignant tumors. Our previous study showed that elevated peripheral blood platelet counts may be an adverse prognostic factor of anaplastic thyroid carcinoma (ATC) patients, indicating that platelets may promote ATC progression. In the present study, we aimed to identify the role of platelets in ATC cell invasion and migration and to explore the underlying mechanisms. We found that platelets can promote the invasive and migratory of ATC cells, which may be related to the interaction between activated platelet-secreted chemokine (C-C motif) ligand 3 (CCL3) and its receptor CCR5. The interaction was shown to induce the upregulation of matrix metalloproteinase (MMP)-1 via NF-κB pathway. These findings could provide a new idea for the research of targeted platelets to inhibit tumor metastasis.

7.
J Natl Compr Canc Netw ; 17(6): 703-710, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31200353

RESUMO

BACKGROUND: The goal of this study was to explore the value of adding neoadjuvant chemotherapy (NACT) or adjuvant chemotherapy (ACT) to concurrent chemoradiotherapy (CCRT) in patients with nasopharyngeal carcinoma (NPC) with different risks of treatment failure. PATIENTS AND METHODS: A total of 2,263 eligible patients with stage III-IVb NPC treated with CCRT ± NACT or ACT were included in this retrospective study. Distant metastasis-free survival (DMFS), overall survival, and progression-free survival were calculated using the Kaplan-Meier method and differences were compared using the log-rank test. RESULTS: Patients in the low-risk group (stage N0-1 disease and Epstein-Barr virus [EBV] DNA <4,000 copies/mL) who received NACT followed by CCRT achieved significantly better 5-year DMFS than those treated with CCRT alone (96.2% vs 91.3%; P= .008). Multivariate analyses also demonstrated that additional NACT was the only independent prognostic factor for DMFS (hazard ratio, 0.42; 95% CI, 0.22-0.80; P=.009). In both the intermediate-risk group (stage N0-1 disease and EBV DNA ≥4,000 copies/mL and stage N2-3 disease and EBV DNA <4,000 copies/mL) and the high-risk group (stage N2-3 disease and EBV DNA ≥4,000 copies/mL), comparison of NACT or ACT + CCRT versus CCRT alone indicated no significantly better survival for all end points. CONCLUSIONS: The addition of NACT to CCRT could reduce distant failure in patients with low risk of treatment failure.

8.
J Mol Med (Berl) ; 97(8): 1213-1214, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203376

RESUMO

In Figure 7f the panel for c-myc of MDA-MB-468 was erroneously duplicated. The corrected version of the figure is shown in this paper. This correction does not influence the conclusion of the study and we sincerely apologize for this oversight.

9.
Nat Genet ; 51(7): 1131-1136, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31209392

RESUMO

Epstein-Barr virus (EBV) infection is ubiquitous worldwide and is associated with multiple cancers, including nasopharyngeal carcinoma (NPC). The importance of EBV viral genomic variation in NPC development and its striking epidemic in southern China has been poorly explored. Through large-scale genome sequencing of 270 EBV isolates and two-stage association study of EBV isolates from China, we identify two non-synonymous EBV variants within BALF2 that are strongly associated with the risk of NPC (odds ratio (OR) = 8.69, P = 9.69 × 10-25 for SNP 162476_C; OR = 6.14, P = 2.40 × 10-32 for SNP 163364_T). The cumulative effects of these variants contribute to 83% of the overall risk of NPC in southern China. Phylogenetic analysis of the risk variants reveals a unique origin in Asia, followed by clonal expansion in NPC-endemic regions. Our results provide novel insights into the NPC endemic in southern China and also enable the identification of high-risk individuals for NPC prevention.

10.
Int J Cancer ; 145(10): 2873-2883, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31044420

RESUMO

We analyzed the number of circulating tumor cells (CTCs) and Epstein-Barr virus DNA (EBV DNA) for diagnosis, monitoring and prognosis of patients with metastatic nasopharyngeal carcinoma (mNPC). The levels of CTCs and EBV DNA were measured at baseline and after first-line chemotherapy in 148 mNPC patients prospectively enrolled between December 2014 and August 2016. We also collected 122 non-mNPC cases within the same time frame for examining CTCs and EBV DNA at baseline. In 270 NPC patients, we observed improved specificity (86.0% vs. 41.0%) and inferior sensitivity (42.3% vs. 81.3%) of CTCs as compared to EBV DNA for diagnosis of distant metastasis. mNPC patients were stratified into unfavorable and favorable prognostic groups, respectively, based on CTC of 12 at baseline and 1 after first-line chemotherapy and EBV DNA of 10,000 at baseline and 4,000 after first-line chemotherapy. Conversion of baseline unfavorable CTCs and EBV DNA to favorable after first-line chemotherapy was associated with significantly longer progression-free survival (PFS) and overall survival (OS) compared to patients with unfavorable CTCs and EBV DNA at both time points. Among patients with a complete/partial response as per imaging evaluation, favorable CTCs and EBV DNA levels after first-line chemotherapy were associated with significantly longer PFS and OS. In conclusion, our data demonstrated the number of CTCs and EBV DNA before, after and during first-line chemotherapy were strong predictive markers for mNPC patients. When utilized in conjunction with imaging studies, CTCs and EBV DNA could provide additional prognostic information.

11.
Cancer Cell ; 35(6): 932-947.e8, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31130341

RESUMO

We performed genomic and transcriptomic sequencing of 133 combined hepatocellular and intrahepatic cholangiocarcinoma (cHCC-ICC) cases, including separate, combined, and mixed subtypes. Integrative comparison of cHCC-ICC with hepatocellular carcinoma and intrahepatic cholangiocarcinoma revealed that combined and mixed type cHCC-ICCs are distinct subtypes with different clinical and molecular features. Integrating laser microdissection, cancer cell fraction analysis, and single nucleus sequencing, we revealed both mono- and multiclonal origins in the separate type cHCC-ICCs, whereas combined and mixed type cHCC-ICCs were all monoclonal origin. Notably, cHCC-ICCs showed significantly higher expression of Nestin, suggesting Nestin may serve as a biomarker for diagnosing cHCC-ICC. Our results provide important biological and clinical insights into cHCC-ICC.

12.
J Biol Chem ; 294(25): 9734-9745, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31073033

RESUMO

Early diagnosis of nasopharyngeal carcinoma (NPC) is difficult because of a lack of specific symptoms. Many patients have advanced disease at diagnosis, and these patients respond poorly to treatment. New treatments are therefore needed to improve the outcome of NPC. To better understand the molecular pathogenesis of NPC, here we used an NPC cell line in a genome-wide CRISPR-based knockout screen to identify the cellular factors and pathways essential for NPC (i.e. dependence factors). This screen identified the Moz, Ybf2/Sas3, Sas2, Tip60 histone acetyl transferase complex, NF-κB signaling, purine synthesis, and linear ubiquitination pathways; and MDM2 proto-oncogene as NPC dependence factors/pathways. Using gene knock out, complementary DNA rescue, and inhibitor assays, we found that perturbation of these pathways greatly reduces the growth of NPC cell lines but does not affect growth of SV40-immortalized normal nasopharyngeal epithelial cells. These results suggest that targeting these pathways/proteins may hold promise for achieving better treatment of patients with NPC.

13.
Nat Commun ; 10(1): 1858, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-31015415

RESUMO

N6-methyladenosine (m6A) modification is an important mechanism in miRNA processing and maturation, but the role of its aberrant regulation in human diseases remained unclear. Here, we demonstrate that oncogenic primary microRNA-25 (miR-25) in pancreatic duct epithelial cells can be excessively maturated by cigarette smoke condensate (CSC) via enhanced m6A modification that is mediated by NF-κB associated protein (NKAP). This modification is catalyzed by overexpressed methyltransferase-like 3 (METTL3) due to hypomethylation of the METTL3 promoter also caused by CSC. Mature miR-25, miR-25-3p, suppresses PH domain leucine-rich repeat protein phosphatase 2 (PHLPP2), resulting in the activation of oncogenic AKT-p70S6K signaling, which provokes malignant phenotypes of pancreatic cancer cells. High levels of miR-25-3p are detected in smokers and in pancreatic cancers tissues that are correlated with poor prognosis of pancreatic cancer patients. These results collectively indicate that cigarette smoke-induced miR-25-3p excessive maturation via m6A modification promotes the development and progression of pancreatic cancer.


Assuntos
Carcinoma Ductal Pancreático/patologia , Metiltransferases/metabolismo , MicroRNAs/metabolismo , Neoplasias Pancreáticas/patologia , Fumaça/efeitos adversos , Tabaco/toxicidade , Adenosina/análogos & derivados , Adenosina/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Ductal Pancreático/sangue , Carcinoma Ductal Pancreático/etiologia , Carcinoma Ductal Pancreático/mortalidade , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Proteínas Correpressoras/metabolismo , Metilação de DNA , Progressão da Doença , Células Epiteliais/patologia , Feminino , Seguimentos , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Masculino , Metiltransferases/genética , MicroRNAs/sangue , Pessoa de Meia-Idade , Proteínas Nucleares/metabolismo , Ductos Pancreáticos/citologia , Ductos Pancreáticos/patologia , Neoplasias Pancreáticas/sangue , Neoplasias Pancreáticas/etiologia , Neoplasias Pancreáticas/mortalidade , Fosfoproteínas Fosfatases/genética , Fosfoproteínas Fosfatases/metabolismo , Prognóstico , Regiões Promotoras Genéticas/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Fumar/efeitos adversos , Fumar/sangue , Regulação para Cima
14.
Theranostics ; 9(4): 1115-1124, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30867819

RESUMO

Rationale: Epstein-Barr virus (EBV) is associated with multiple malignancies with expression of viral oncogenic proteins and chronic inflammation as major mechanisms contributing to tumor development. A less well-studied mechanism is the integration of EBV into the human genome possibly at sites which may disrupt gene expression or genome stability. Methods: We sequenced tumor DNA to profile the EBV sequences by hybridization-based enrichment. Bioinformatic analysis was used to detect the breakpoints of EBV integrations in the genome of cancer cells. Results: We identified 197 breakpoints in nasopharyngeal carcinomas and other EBV-associated malignancies. EBV integrations were enriched at vulnerable regions of the human genome and were close to tumor suppressor and inflammation-related genes. We found that EBV integrations into the introns could decrease the expression of the inflammation-related genes, TNFAIP3, PARK2, and CDK15, in NPC tumors. In the EBV genome, the breakpoints were frequently at oriP or terminal repeats. These breakpoints were surrounded by microhomology sequences, consistent with a mechanism for integration involving viral genome replication and microhomology-mediated recombination. Conclusion: Our finding provides insight into the potential of EBV integration as an additional mechanism mediating tumorigenesis in EBV associated malignancies.

16.
Leukemia ; 33(6): 1451-1462, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30546078

RESUMO

Extranodal natural killer T-cell lymphoma (nasal type; NKTCL) is an aggressive malignancy strongly associated with Epstein-Barr virus (EBV) infection. However, the role of EBV in NKTCL development is unclear, largely due to the lack of information about EBV genome and transcriptome in NKTCL. Here, using high-throughput sequencing, we obtained whole genome (n = 27) and transcriptome datasets (n = 18) of EBV derived from NKTCL tumor biopsies. We assembled 27 EBV genomes and detected an average of 1,152 single nucleotide variants and 44.8 indels (<50 bp) of EBV per sample. We also identified frequent focal EBV genome deletions and integrated EBV fragments in the host genome. Moreover, Phylogenetic analysis revealed that NKTCL-derived EBVs are closely clustered; transcriptome analysis revealed less activation of both latent and lytic genes and larger amount of T-cell epitope alterations in NKTCL, as compared with other EBV-associated cancers. Furthermore, we observed transcriptional defects of the BARTs miRNA by deletion, and the disruption of host NHEJ1 by integrated EBV fragment, implying novel pathogenic mechanisms of EBV. Taken together, we reported for the first time global mutational and transcriptional profiles of EBV in NKTCL clinical samples, revealing important somatic events of EBV and providing insights to better understanding of EBV's contribution in tumorigenesis.


Assuntos
Infecções por Vírus Epstein-Barr/genética , Genoma Viral , Herpesvirus Humano 4/genética , Linfoma Extranodal de Células T-NK/genética , Células T Matadoras Naturais/metabolismo , Transcriptoma , Proteínas Virais/genética , Adulto , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/virologia , Feminino , Regulação Viral da Expressão Gênica , Genômica/métodos , Humanos , Linfoma Extranodal de Células T-NK/epidemiologia , Linfoma Extranodal de Células T-NK/virologia , Masculino , Mutação , Células T Matadoras Naturais/virologia , Sequenciamento Completo do Genoma
17.
Nat Commun ; 9(1): 5009, 2018 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-30479336

RESUMO

Epstein-Barr virus (EBV)-associated epithelial cancers, including nasopharyngeal carcinoma (NPC) and approximately 10% of gastric cancers, termed EBVaGC, represent 80% of all EBV-related malignancies. However, the exact role of EBV in epithelial cancers remains elusive. Here, we report that EBV functions in vasculogenic mimicry (VM). Epithelial cancer cells infected with EBV develop tumor vascular networks that correlate with tumor growth, which is different from endothelial-derived angiogenic vessels and is VEGF-independent. Mechanistically, activation of the PI3K/AKT/mTOR/HIF-1α signaling cascade, which is partly mediated by LMP2A, is responsible for EBV-induced VM formation. Both xenografts and clinical samples of NPC and EBVaGC exhibit VM histologically, which are correlated with AKT and HIF-1α activation. Furthermore, although anti-VEGF monotherapy shows limited effects, potent synergistic antitumor activities are achieved by combination therapy with VEGF and HIF-1α-targeted agents. Our findings suggest that EBV creates plasticity in epithelial cells to express endothelial phenotype and provides a novel EBV-targeted antitumor strategy.

18.
Cell Prolif ; : e12536, 2018 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-30341788

RESUMO

OBJECTIVES: The present study aimed to reveal expression status of the neddylation enzymes in HNSCC and to elucidate the anticancer efficacy and the underlying mechanisms of inhibiting neddylation pathway. MATERIALS AND METHODS: The expression levels of neddylation enzymes were estimated by Western blotting in human HNSCC specimens and bioinformatics analysis of the cancer genome atlas (TCGA) database. Cell apoptosis was evaluated by Annexin V fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) stain and fluorescence-activated cell sorting (FACS). Small interfering RNA (siRNA) and the CRISPR-Cas9 system were used to elucidate the underlying molecular mechanism of MLN4924-induced HNSCC apoptosis. RESULTS: Expression levels of NAE1 and UBC12 were prominently higher in HNSCC tissues than that in normal tissues. Inactivation of the neddylation pathway significantly inhibited malignant phenotypes of HNSCC cells. Mechanistic studies revealed that MLN4924 induced the accumulation of CRL ligase substrate c-Myc that transcriptionally activated pro-apoptotic protein Noxa, which triggered apoptosis in HNSCC. CONCLUSIONS: These findings determined the over-expression levels of neddylation enzymes in HNSCC and revealed novel mechanisms underlying neddylation inhibition induced growth suppression in HNSCC cells, which provided preclinical evidence for further clinical evaluation of neddylation inhibitors (eg, MLN4924) for the treatment of HNSCC.

19.
Aging (Albany NY) ; 10(8): 1884-1901, 2018 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-30103211

RESUMO

Anillin (ANLN) is an actin-binding protein essential for assembly of cleavage furrow during cytokinesis. Although reportedly overexpressed in various human cancers, its role in hepatocellular carcinoma (HCC) is unclear. To address this issue, we confirmed that in 436 liver samples obtained from surgically removed HCC tissues, higher ANLN expression was detected in tumor tissues than in adjacent non-tumor tissues of HCC as measured by immunohistochemistry, quantitative real-time PCR and western blotting. Correlation and Kaplan-Meier analysis revealed that patients with higher ANLN expression were associated with worse clinical outcomes and a shorter survival time, respectively. Moreover, ANLN inhibition resulted in growth restraint, reduced colony formation, and a lower sphere number in suspension culture. Mechanistically, ANLN deficiency induced an increasing number of multinucleated cells along with the activation of apoptosis signaling and DNA damage checkpoints. Furthermore, HBV infection increased ANLN expression by inhibiting the expression of microRNA (miR)-15a and miR-16-1, both of which were identified as ANLN upstream repressors by targeting its 3' untranslated region. Thus, we conclude that ANLN promotes tumor growth by ways of decreased apoptosis and DNA damage. Expression level of ANLN significantly influences the survival probability of HCC patients and may represent a promising prognostic biomarker.

20.
PLoS Pathog ; 14(7): e1007208, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-30052682

RESUMO

Epstein-Barr virus (EBV) is a human cancer-related virus closely associated with lymphoid and epithelial malignancies, and EBV glycoprotein B (gB) plays an essential role in viral entry into both B cells and epithelial cells by promoting cell-cell fusion. EBV gB is exclusively modified with high-mannose-linked N-glycans and primarily localizes to the endoplasmic reticulum (ER) with low levels on the plasma membrane (PM). However, the mechanism through which gB is regulated within host cells is largely unknown. Here, we report the identification of F-box only protein 2 (FBXO2), an SCF ubiquitin ligase substrate adaptor that preferentially binds high-mannose glycans and attenuates EBV infectivity by targeting N-glycosylated gB for degradation. gB possesses seven N-glycosylation sites, and FBXO2 directly binds to these high-mannose moieties through its sugar-binding domain. The interaction promotes the degradation of glycosylated gB via the ubiquitin-proteasome pathway. Depletion of FBXO2 not only stabilizes gB but also promotes its transport from the ER to the PM, resulting in enhanced membrane fusion and viral entry. FBXO2 is expressed in epithelial cells but not B cells, and EBV infection up-regulates FBXO2 levels. In summary, our findings highlight the significance of high-mannose modification of gB and reveal a novel host defense mechanism involving glycoprotein homeostasis regulation.

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