MiRNAs deregulated by LMP2A in nasopharyngeal cancer
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE25682 | GEO | 2023/02/04
REPOSITORIES: GEO
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Project description:Latent infection with Epstein-Barr virus (EBV) is recognised as a factor in the pathogenesis of nasopharyngeal carcinoma (NPC). We found that EBV encoded Latent membrane protein 2A (LMP2A) enhances lipid accumulation significantly in NPC cells. We used microarrays to identify differential genes regulated by LMP2A in NPC cell lines.
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Project description:Epstein-Barr virus (EBV) infects human B cells and reprograms them to allow virus replication and persistence. One key viral factor in this process is latent membrane protein 2A (LMP2A), which has been described as a B cell receptor (BCR) mimic promoting malignant transformation. However, how LMP2A signaling contributes to tumorigenesis remains elusive. By systematically comparing LMP2A and BCR signaling using quantitative phosphoproteomics and transcriptome profiling, we identified molecular mechanisms through which LMP2A affects B cell biology. Consistent with previous literature, we found that LMP2A mimics a subset of BCR signaling events, including tyrosine-phosphorylation of the kinase SYK, the calcium initiation complex consisting of BLNK, BTK, PLC2, and its downstream transcription factor NFAT. However, the vast majority of LMP2A-induced signaling events markedly differed from those induced by BCR stimulation. These included differential phosphorylation of kinases, phosphatases, adaptor proteins, transcription factors such as NFB and TCF3, as well as widespread changes in the transcriptional output of LMP2A-expressing B cells. LMP2A affected apoptosis and cell cycle checkpoints by dysregulating the expression of apoptosis regulators such as Bcl-xL and the tumor suppressor retinoblastoma-associated protein (RB1). Accordingly, LMP2A cooperated with drivers of Burkitt lymphoma, overexpressed MYC and an oncogenic cyclin D3 mutant, by counteracting the pro-apoptotic effects of MYC and by further inhibiting RB1 function to promote cell growth. Our results indicate that LMP2A rewires rather than mimics BCR signaling, promoting a signaling output that predisposes EBV-infected B cells to hyperproliferation and eventual malignant transformation.
2020-09-22 | PXD018566 | Pride
Project description:Abstract: Epstein-Barr virus (EBV) infects germinal center (GC) B cells and establishes persistent infection in memory B cells. EBV-infected B cells sometimes cause B cell malignancies in humans with T- or NK-cell deficiency. We now find EBV-encoded Latent Membrane Protein 2A (LMP2A) to mimic B cell antigen receptor (BCR) signaling in murine GC B cells, causing altered humoral immune responses and autoimmune diseases. Investigation of the impact of LMP2A on B cell differentiation in mice that conditionally express LMP2A in GC B cells, or all B-lineage cells, found LMP2A expression enhanced not only BCR signals but also plasma-cell differentiation, in vitro and in vivo. Conditional LMP2A expression in GC B cells resulted in preferential selection of low-affinity antibody–producing B-cells despite apparently normal GC formation. GC B cell-specific LMP2A expression led to systemic lupus erythematosus-like autoimmune phenotypes in an age-dependent manner. Epigenetic profiling of LMP2A B cells found increased H3K27ac and H3K4me1 signals at the Zbtb20 locus. We conclude that LMP2A reduces the stringency of GC B cell selection and may contribute to persistent EBV infection and pathogenesis by providing GC B cells with pro-survival signals. Significance Statement: Epstein-Barr virus (EBV) is a human herpesvirus that establishes persistent infection of the B-cell compartment. EBV is associated with autoimmune diseases, including systemic lupus erythematosus (SLE). However, the molecular mechanisms by which EBV contributes to autoimmunity remain unclear. We used transgenic mouse models to study the role of EBV-encoded Latent membrane protein 2A (LMP2A), which mimics B-cell receptor signaling. Interestingly, LMP2A not only enhanced B-cell survival, but also upregulated the transcription factor Zbtb20 and promoted plasma cell differentiation. When expressed late in B-cell development, LMP2A also caused prominent features of SLE, including autoantibody production with kidney immune complex deposition. Our findings suggest that LMP2A has important roles in B cell activation, differentiation and the development of EBV-associated autoimmune diseases.
2015-10-01 | GSE71408 | GEO
Project description:Survival of all B cells depends on signals from the B-cell receptor (BCR). In BCRnegative B cells the latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) replaces this survival signal and might play a role in the development of EBV-positive Hodgkin lymphomas and posttransplantation lymphoproliferative disease. In these BCR-negative cells LMP2A provides a ‘tonic’ signal similar to BCR’s constitutive expression in the absence of antigen in order to maintain activating signaling pathways common to both receptor molecules. In most latently EBV-infected B cells LMP2A and BCR are co-expressed but it is largely unclear what LMP2A contributes with respect to B-cell activation, proliferation and viral latency in these BCR-positive cells. A common model suggests that LMP2A maintains herpesviral latency by blocking BCR-mediated signals but how LMP2A could serve both antithetical ends in BCRnegative and BCR-positive cells is elusive. Our comparative analysis of BCR and LMP2A now indicates that LMP2A is a true BCR mimic that dominates BCR-operated signaling pathways in EBV-infected, BCR-positive cells to provide activation signals, support stable infections in vivo and allow exit from latency. These findings suggest that LMP2A co-opts the situation in anergic B cells, where continuous BCR signaling results in maintenance of the anergic state accompanied by unresponsiveness to acute BCR stimulation. The microarray experiment was used to compare effects of BCR and LMP2A on gene expression regulation. EBV's LMP2A and the human BCR activate similar cellular target genes; some genes are regulated solely by BCR or LMP2A, no gene is counter regulated A 12 chip study using cDNA from three separate 2525 LMP2A knockout LCL cultures and three separate 3696.10 LMP2A:mCD69 LCL cultures; each culture tested before and after 90 min stimulation of the BCR and LMP2A:mCD69, respectively.
2011-01-01 | E-GEOD-25434 | biostudies-arrayexpress
Project description:Survival of all B cells depends on signals from the B-cell receptor (BCR). In BCRnegative B cells the latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) replaces this survival signal and might play a role in the development of EBV-positive Hodgkin lymphomas and posttransplantation lymphoproliferative disease. In these BCR-negative cells LMP2A provides a ‘tonic’ signal similar to BCR’s constitutive expression in the absence of antigen in order to maintain activating signaling pathways common to both receptor molecules. In most latently EBV-infected B cells LMP2A and BCR are co-expressed but it is largely unclear what LMP2A contributes with respect to B-cell activation, proliferation and viral latency in these BCR-positive cells. A common model suggests that LMP2A maintains herpesviral latency by blocking BCR-mediated signals but how LMP2A could serve both antithetical ends in BCRnegative and BCR-positive cells is elusive. Our comparative analysis of BCR and LMP2A now indicates that LMP2A is a true BCR mimic that dominates BCR-operated signaling pathways in EBV-infected, BCR-positive cells to provide activation signals, support stable infections in vivo and allow exit from latency. These findings suggest that LMP2A co-opts the situation in anergic B cells, where continuous BCR signaling results in maintenance of the anergic state accompanied by unresponsiveness to acute BCR stimulation. The microarray experiment was used to compare effects of BCR and LMP2A on gene expression regulation. EBV's LMP2A and the human BCR activate similar cellular target genes; some genes are regulated solely by BCR or LMP2A, no gene is counter regulated
2011-01-01 | GSE25434 | GEO
Project description:We have developed a transgenic mouse model for Epstein-Barr virus-associated Burkitt's lymphoma. Transgenic mice that express LMP2A and MYC in B cells develop spontaneous lymph node tumors at different rates. Tumor onset occurs at approximately 40-60 days in LMP2A/λ-MYC mice and at 100-200 days in λ-MYC mice. This study compared total gene expression in the tumor cells from each genotype, as well as in B cells isolated from 3 week old mice prior to tumor onset. Comparison of total gene expression in tumor cells from LMP2A/λ-MYC and λ-MYC transgenic mice identified a short list of differentially expressed genes. Comparison of gene expression in B cells from the spleens of 3 week old mice, in contrast, identified a 10-fold increase in the number of differentially expressed genes. B cells from the spleens of 3 week old LMP2A/λ-MYC (n=5), λ-MYC (n=5), LMP2A (n=3), and WT (n=3) transgenic mice were purified using magnetic-activated cell sorting (MACS) beads purchased from Miltenyi for CD19 positive selection. Total RNA was isolated from these purified B cells, as well as from cervical lymph node tumor cells that developed in LMP2A/λ-MYC (n=7) and λ-MYC (n=5) transgenic mice using RNeasy RNA extraction kit from QIAGEN. Cervical lymph node tumor cells were >90% positive for the B cell marker B220, and were not further purified. Total gene expression was assessed in each sample, along with heart and brain reference samples using MouseRef-8 v2.0 Expression Bead Chips purchased from Illumina. GeneSpring analysis software was used to analyze the expression data and identify significantly differentially expressed genes (fold change >1.5-fold and false discovery rate< 0.05).
2011-10-25 | E-GEOD-26918 | biostudies-arrayexpress
Project description:Gene expression profile of splenic B cells (CD19+) from transgenic mice expressing the Epstein-Barr virus (EBV) latent membrane proteins (LMP) 1 and/or LMP2A. Freshly harvested primary B cells were profiled. B lymphocytes from transgenic LMP1, LMP2A, LMP1/2A mice and negative littermates were profiled from 6 month old adult mice; lymphoma cells were passaged in SCID mice and profiled for three LMP1 positive lymphomas and one negative lymphoma.
2012-09-01 | GSE38954 | GEO
Project description:In this study, we have investigated the effect of LMP2A on gene expression in normal human GC B cells using a non-viral vector based system Keywords: transfection of viral oncogene in normal human B cells Gene expression was compared between LMP2A-transfected and control vector-transfected GC B cells from three patients. RNA from the FACS-sorted transfected GC B cells was amplified. 10ug of fragmented cRNA was hybridized to HG-U133 Plus 2.0 microarrays. Differentially expressed probe sets were identified using limma with a fold change >1.3 and p < 0.01
2013-04-19 | E-GEOD-46143 | biostudies-arrayexpress
Project description:We have developed a transgenic mouse model for Epstein-Barr virus-associated Burkitt's lymphoma. Transgenic mice that express LMP2A and MYC in B cells develop spontaneous lymph node tumors at different rates. Tumor onset occurs at approximately 40-60 days in LMP2A/λ-MYC mice and at 100-200 days in λ-MYC mice. This study compared total gene expression in the tumor cells from each genotype, as well as in B cells isolated from 3 week old mice prior to tumor onset. Comparison of total gene expression in tumor cells from LMP2A/λ-MYC and λ-MYC transgenic mice identified a short list of differentially expressed genes. Comparison of gene expression in B cells from the spleens of 3 week old mice, in contrast, identified a 10-fold increase in the number of differentially expressed genes.
2011-10-26 | GSE26918 | GEO