Project description:Epstein Barr Virus (EBV) driven B-cell neoplasms arise from reactivation of latently infected B-cells. In a subset of patients EBV drives a polymorphous lymphoproliferative disorder (LPD) in which B-cell differentiation is retained. Spontaneous EBV reactivation following B-cell mitogen stimulation provides a potential model of polymorphic EBV-driven LPD. We have developed an in vitro model of plasma cell (PC) differentiation from peripheral blood memory B-cells. To assess the frequency and phenotypes of EBV-associated populations derived during differentiation we analyzed 8 differentiations at the PC stage, with a targeted single cell gene expression panel. We identified subpopulations of EBV-gene expressing cells with PC and/or B-cell expression features in differentiations from all tested donors. EBV-associated cells varied in frequency ranging from 3-28% of cells. Most EBV-associated cells expressed PC genes such as XBP1 or MZB1 and in all samples these included a quiescent PC fraction lacking cell cycle gene expression. With increasing EBV-associated cells, populations with B-cell features became prominent, co-expressing germinal centre (GC) and activated B-cell gene patterns. The presence of highly proliferative EBV-associated cells was linked to retained MS4A1/CD20 expression and IGHM and IGHD co-expression, while IGHM only and class-switched cells were enriched in quiescent PC fractions. Thus, patterns of gene expression in primary EBV reactivation are consistent with recently proposed models relating EBV-mediated transformation in lymphoblastoid cell lines to features of GC B-cells, and suggest a particular association between spontaneously developing EBV-expansions and IgM+ IgD+ non-switched B-cells.
Project description:We examined the viral epitranscriptome in EBV transformed lymphoblastoid cell lines (LcLs) and EBV-positive Burkitt's lymphoma, Akata cells, using methylated RNA immunoprecipitation followed by sequencing (MeRIP-seq). Biological replicates of ribo-RNA deleted mRNA of each cell type were prepared for MeRIP-seq followed by peak calling using the exome Peak package with settings for stringent peak calling on both strands of the genome.
Project description:Extranodal NK/T-cell, nasal type (hereinafter, nasal T/NK lymphoma), is a distinct clinicopahtologic entity highly associated with EBV. Among nasal T/NK lymphoma, some cases are developed from the long-lasting EBV infection termed chronic active EBV (CAEBV) infection.The clonal expansion of EB infected T- or NK cell are seen in patients with both nasal T/NK lymphoma and CAEBV infection, suggesting that two diseases might partly share the similar mechanism by which EBV affect host cellular genes. Question has thus arisen why a subset of patients with CAEB infection develop into nasal T/NK lymphoma. This study aimed to investigate the virus-host interaction in EBV-associated lymphoma. Keywords = nasak NK/T lymphoma Keywords = chronic active EBV infection Keywords: other
Project description:Background: In several types of malignancies, especially EBV-associated nasopharyngeal carcinomas, high Galectin-9 (Gal-9) expression is indicative of an aggressive tumor phenotype. The contribution of Gal-9 to the oncogenesis of B-cell lymphomas (BCLs) has not yet been investigated. Methods: The expression of Gal-9, STING, and EBNA1 was measured by immunohistochemical (IHC) staining on tumor sections from 66 BCL patients. Artificial EBV infection of normal primary B cells in vitro was used as an experimental model. The dynamic changes of the transcriptome of EBV-infected B cells undergoing transformation were investigated by bulk RNA-sequencing and bioinformatics analysis. The oncogenic role of Gal-9 was investigated in vitro by addition of recombinant Gal-9 to EBV-infected primary B-cells, and growth assays. The underlying molecular mechanisms were investigated by immunoblotting and immunofluorescent (IF) staining, CHIP and luciferase reporter assays. Results: In clinical specimens of BCLs, Gal-9 expression was significantly associated with tumor stage, latent EBV infection and abundance of the viral latent protein EBNA1. Looking at the transcriptome changes occurring in vitro during EBV-driven B-cell transformation, we could identify a series of genes undergoing long term activation and remaining highly expressed in mature LCLs. The Gal-9 gene is one of them. Its expression is enhanced during the transformation process at the mRNA level and even more at the protein level. This up-regulation results at least in part from its transactivation by EBNA1 which can bind its promoter. Reciprocally, we find that addition of extra-cellular Gal-9 promotes B-cell transformation and establishment of the latent phase of EBV-infection. Concomitantly, extra-cellular Gal-9 blocks STING signaling and enhances STAT3 phosphorylation. Inhibition of Sting signaling or STAT3 phosphorylation blocks B-cell transformation, even in the presence of Gal-9. Conclusion: our data unveil a role of amplification and acceleration for Gal-9 in the process of EBV-driven B-cell transformation. This process might be relevant to the pathogenesis of EBV-associated BCLs.
Project description:Nasal T/NK lymphoma is a unique subtype of non-Hodgkin lymphoma (NHL) that is aggressive and incurable closely associated with Epstein-Barr virus (EBV)3. The clonal expansion of EB infected T- or NK cell is also seen in patients with chronic active EBV (CAEBV) infection, suggesting that two diseases might partly share a similar mechanism by which EBV affect host cellular genes. In order to understand the pathogenesis of EBV-associated T/NK lymphoproliferative disorders (LPD) and design new therapies, we employed a novel EBV DNA microarray to compare patterns of EBV expression in SNK/T cells established from EBV-associated T/NK LPD. Keywords: parallel sample
Project description:Whilst the association of Epstein-Barr virus (EBV) with Burkitt lymphoma (BL) has long been recognized, the precise role of the virus in BL pathogenesis is not fully resolved. EBV can be lost spontaneously from some BL cell lines, and these EBV-loss lymphoma cells reportedly have a survival disadvantage. We have generated an extensive panel of EBV-loss clones from multiple BL backgrounds and examined their phenotype comparing them to their isogenic EBV-positive counterparts. Whilst loss of EBV from BL cells is rare, it is consistently associated with an enhanced predisposition to undergo apoptosis and reduced tumorigenicity in vivo. We investigated whether there were common gene expression changes between EBV-positive and loss clones derived for four endemic Burkitt lyphoma cell lines that could explain the apoptosis sensitivity of clones that had lost EBV.
Project description:RNAseq was used to identify host and EBV viral transcriptome changes in CHAF1B knock-out Akata EBV+ cells. CHAF1B KO Akata EBV+ cells were subjected to RNAseq analysis. The Akata EBV+ cells expressing control sgRNA was used as the control.
Project description:STAT3 encodes an oncogenic transcription factor which is activated via various signalling pathways or Epstein Barr virus (EBV)-infection. The tumor cells of Hodgkin lymphoma (HL) are derived from germinal center B-cells and transformed by chromosomal rearrangements, aberrant signal transduction, downregulation of transcription factors mediating B-cell differentiation, and EBV-infection. HL cell lines represent useful models to investigate the molecular pathology and deduced treatment options in this malignancy. Using cell line L-540, we have recently shown that constitutively activated STAT3 drives aberrant expression of hematopoietic NKL homeobox gene HLX. Here, we analyzed HL cell line AM-HLH which is EBV-positive but nevertheless HLX negative. Consistently, AM-HLH expressed decreased levels of STAT3 proteins which were additionally inactivated and located in the cytoplasm. Combined genomic and gene expression profiling data revealed amplified and overexpressed candidates involved in opposed regulation of STAT3 and EBV. Subsequent analyses demonstrated that IRF4 and NFATC inhibited STAT3 expression. However, treatment with IL6 or IL27 activated STAT3, elevated expression of HLX and MIR155, and inhibited IRF4. MIR155 (STAT3 target gene) and BCL11A and SPIB (target genes of HLX) are described as suppressors and activators of EBV and showed reduced and elevated expression levels in AM-HLH, respectively. Taken together, this cell line deals with two conflicting oncogenic drivers, namely JAK2-STAT3-signalling and EBV-infection but is sensitive to cytokine signalling, mediating a switch between these aberrant pathways. Thus, AM-HLH represents an interesting cell line model to study the pathogenic roles of STAT3 and EBV and their therapeutic implications in HL.