Project description:EBV-positive cell lines were assayed for expression of EBV miRNAs. The names of the miRNAs are from miRBase from Fall 2007. Microarray probes are tandem complements of the mature miRNA sequence. We assayed Burkitt's lymphoma (BL), Nasopharyngeal carcinoma, post-transplant lymphoproliferative disease (PTLD), primary effusion lymphoma, and lymphoblastoid cell lines. We also assayed primary B cells that were infected with the B95-8 strain of EBV, which was found to express EBV miRNAs as early as 20 hours post infection. We have found PTLD and BLs from HIV-positive donors both express EBV miRNAs. These types of cell lines have not previously been found to express viral miRNAs. We have found that cells that support type I and type II latency express only the BART miRNAs, whereas cells that support type III latency express BART and BHRF1 miRNAs. Furthermore, BL cell lines that spontaneously lose EBV express levels of the viral miRNAs that are at least 5-fold lower than cell lines that do not lose EBV.
Project description:EBV-positive cell lines were assayed for expression of EBV miRNAs. The names of the miRNAs are from miRBase from Fall 2007. Microarray probes are tandem complements of the mature miRNA sequence. We assayed Burkitt's lymphoma (BL), Nasopharyngeal carcinoma, post-transplant lymphoproliferative disease (PTLD), primary effusion lymphoma, and lymphoblastoid cell lines. We also assayed primary B cells that were infected with the B95-8 strain of EBV, which was found to express EBV miRNAs as early as 20 hours post infection. We have found PTLD and BLs from HIV-positive donors both express EBV miRNAs. These types of cell lines have not previously been found to express viral miRNAs. We have found that cells that support type I and type II latency express only the BART miRNAs, whereas cells that support type III latency express BART and BHRF1 miRNAs. Furthermore, BL cell lines that spontaneously lose EBV express levels of the viral miRNAs that are at least 5-fold lower than cell lines that do not lose EBV. In total, 48 samples have been assayed and included in this study. EBV-negative control samples are not included in this data set, but raw and processed data may be requested from the contributors. These EBV-negative cell lines include the Burkitt's lymphoma cell lines, BJAB and Akata-negative, the gastric carcinoma cell line, AGS, and uninfected primary B cells. Of the 48 samples, we have assayed 22 different EBV-positive cell lines and 4 different time points after infection of primary B cells with EBV. Replicates of the majority of cell lines is included in this data set. Replicates are from independent RNA isolations that were then hybridized to individual microarrays.
Project description:Gammaherpesviruses, including the human pathogens Epstein-Barr virus and Kaposi’s sarcoma-associated herpesvirus, establish lifelong latent infection in B cells and are associated with a variety of tumors. In addition to protein coding genes, these viruses encode numerous microRNAs (miRNAs) within their genomes. While putative host targets of EBV and KSHV miRNAs have been previously identified, the specific functions of these miRNAs during in vivo infection are largely unknown. Murine gammaherpesvirus 68 is a natural pathogen of rodents that is genetically related to both EBV and KSHV, and thus serves as an excellent model for the study of EBV and KSHV elements such as miRNAs in the context of infection and disease. However, MHV68 the specific targets of miRNAs remain unknown. Using a technique known as quick CLASH (crosslinking, ligation, and sequencing of hybrids), we have now identified specific, Ago-associated mRNA targets of MHV68 miRNAs during lytic infection, latent infection and reactivation from latency.
Project description:Unlike other EBV-associated human tumors, nearly 100% wild-type p53 gene is found in NPC, p53 protein is also frequently found to accumulate in NPC biopsies. However, the role of p53 in EBV-positive nasopharyngeal carcinoma is unclear. The expression profiles of mRNAs and miRNAs of EBV-positive NPC cells are unknown. To elucidate the function of p53 in EBV-positive NPC, we used the CRISPR-Cas9 gene editing system to p53 knockout C666-1 cells with Epstein-Barr virus and performed mRNA and miRNA sequencing in p53 KO C666-1 and their control cells. Gene Ontology (GO), KEGG and STRING analyses were implemented to identify significant functions, pathways of differentially expressed mRNAs. Through comparative analysis of p53-regulated genes from EBV-positive C666-1 cells and EBV-negative HONE2 cells with p53 target genes from 16 high throughput data sets, we found that the number of target genes and KEGG pathways downregulated by p53 in EBV-positive C666-1 cells were much less than in EBV-negative HONE2 cells, but “p53 signaling pathway” and related cell cycle arrest and apoptosis genes were significantly downregulated after knockout of p53 gene in C666-1 cells. To explore the effect of p53 on cell cycle and apoptosis, we established stable p53 C666-1-KO cell lines with stable expression of exogenous p53-WT and their control cell lines. Using the established cell lines, we observed that stable expression of p53 repressed cell proliferation, increased cell apoptosis and blocked G1/S phase progression. In conclusion, our results show that the accumulated p53 protein in EBV-positive C666-1 cells still has some tumour suppressor functions such as blocking cell-cycle progression and promoting apoptosis, but the ability of p53 to downregulate gene expression is inhibited.
Project description:Primary effusion lymphomas (PELs) are specifically associated with KSHV/HHV-8 infection, and most frequently occur in HIV-positive individuals as lymphomatous effusions in the serous cavities without a detectable solid tumor mass. Most PELs have concomitant EBV infection, suggesting that EBV is an important pathogenetic co-factor, although other as yet unidentified cofactors, such as cellular genetic alterations, are also likely to play a role. Lymphomatous effusions that lack KSHV also occur; these are frequently EBV-associated in the setting of HIV infection. Here we used gene expression profile analysis to determine the viral impact on cellular gene expression and the pathogenesis of these lymphomatous effusions. We used the Affymetrix HG-U133A microarray to analyze the gene expression profile of these effusion lymphomas (three virologic groups: KSHV-positive EBV-positive PELs, KSHV-positive EBV-negative PELs and KSHV-negative EBV-positive lymphomatous effusions). Nine cell lines derived from patients with lymphomatous effusions (three from each virologic group and each cell line was done in duplicates.) and three PEL patient samples were used in the study. Our results suggest that KSHV-positive PELs are very different from KSHV-negative lymphomatous effusions, and the genes that are differentially expressed include apoptosis regulators, cell cycle regulators, transcriptional factors and signal transduction regulators. KSHV clearly plays a dominant role in the phenotype of PEL. Within the KSHV-positive PELs, two subgroups can be identified, which were correlated with their EBV viral status. Among these genes (45 gene probes), four were regulators of the MAP kinase pathway that were up-regulated in the KSHV-positive, EBV-negative PELs, suggesting that in the absence of EBV, events that lead to the activation of the MAP kinase pathway may act as a cofactor for the development of PEL. Next we determined whether we could predict the viral status of the three primary patient cases of PEL based on the 45 gene probes that were differentially expressed in KSHV-positive cell lines according to EBV status (pt. 1: KSHV-positive, EBV-positive; Pt. 2: KSHV-positive, low proportion of EBV-positive; pt. 3: KSHV-positive EBV-negative), and we could.<br><br>Samples:<br>KSHV-positive EBV-positive cell lines: BC-1, BC-2, BC-5 <br>KSHV-positive EBV-negative cell lines: BC-3, BCBL-1, PEL-5 <br>KSHV-negative EBV-positive cell lines: IBL4, SM1, BCKN-1 <br>Patient 1: KSHV-positive, EBV-positive <br>Patient 2: KSHV-positive, EBV-positive (low number of positive cells) <br>Patient 3: KSHV-positive, EBV-negative.
Project description:To identify differentially expressed human and viral miRNAs across a panel of B-cell lines, including several primary effusion lymphomas (PEL). Gammaherpesvirus and host cell microRNAs (miRNAs) together modulate gene expression in normal and malignant cells. Using microRNA microarrays, we determined the expression of mature viral and host cellular miRNAs in a series of B cell tumours that include Kaposi’s Sarcoma-associated herpesvirus (KSHV) infected Primary Effusion Lymphoma (PEL) and Epstein-Barr virus (EBV) infected Burkitt’s lymphoma (BL) cell lines. We show that 35 host miRNAs were constitutively expressed in all the B cell lymphomas and differences in viral miRNA expression were evident between herpesvirus positive tumour types. Furthermore, we show that in PEL, miR-221 and miR-222 expression is defective due to a lack of transcript expression rather than mutation in the miRNA encoding loci. Absence of miR-221 and miR-222 resulted in the enhanced expression of the known target gene p27 (CDKN1B) and reintroduction of miR221 in PEL reduces p27 protein expression.