The Epstein-Barr virus encoded BART miRNAs potentiate tumor growth in vivo.
Ontology highlight
ABSTRACT:
SUBMITTER: Qiu J
PROVIDER: S-EPMC4295875 | biostudies-literature | 2015 Jan
REPOSITORIES: biostudies-literature
Publications
The Epstein-Barr virus encoded BART miRNAs potentiate tumor growth in vivo.
Qiu Jin J Smith Pamela P Leahy Leah L Thorley-Lawson David A DA
PLoS pathogens 20150115 1
The human herpes virus Epstein-Barr virus (EBV) latently infects and drives the proliferation of B lymphocytes in vitro and is associated with several forms of lymphoma and carcinoma in vivo. The virus encodes ~30 miRNAs in the BART region, the function of most of which remains elusive. Here we have used a new mouse xenograft model of EBV driven carcinomagenesis to demonstrate that the BART miRNAs potentiate tumor growth and development in vivo. No effect was seen on invasion or metastasis, and ...[more]
Similar Datasets
Project description:This study assessed the effects of Epstein-Barr virus (EBV) and one form of virally encoded BART long noncoding RNAs (lncRNAs) on cellular expression in epithelial cells grown in vitro and as tumors in vivo determined by high-throughput RNA sequencing of mRNA and small RNAs. Hierarchical clustering based on gene expression distinguished the cell lines from the tumors and distinguished the EBV-positive tumors and the BART tumors from the EBV-negative tumors. EBV and BART expression also induced specific expression changes in cellular microRNAs (miRs) and lncRNAs. Multiple known and predicted targets of the viral miRs, the induced cellular miRs, and lncRNAs were identified in the altered gene set. The changes in expression in vivo indicated that the suppression of growth pathways in vivo reflects increased expression of cellular miRs in all tumors. In the EBV and BART tumors, many of the targets of the induced miRs were not changed and the seed sequences of the nonfunctional miRs were found to have homologous regions within the BART lncRNA. The inhibition of these miR effects on known targets suggests that these induced miRs have reduced function due to sponging by the BART lncRNA. This composite analysis identified the effects of EBV on cellular miRs and lncRNAs with a functional readout through identification of the simultaneous effects on gene expression. Major shifts in gene expression in vivo are likely mediated by effects on cellular noncoding RNAs. Additionally, a predicted property of the BART lncRNA is to functionally inhibit the induced cellular miRs. IMPORTANCE This study identified the total effects of EBV and a viral long noncoding RNA (BART lncRNA) on cellular RNA expression when grown as cells in culture and when grown as tumors in immunodeficient mice. The effects on cellular mRNA expression, lncRNA expression, and cellular and viral miR expression were determined using next-generation sequencing (NGS) and bioinformatics functional analysis. Many cellular growth pathways that are activated during growth in culture are decreased during growth as tumors. This study shows that these changes in expression are accompanied by induction of cellular-growth-inhibitory miRs. However, in the EBV tumors and in tumors expressing the BART lncRNA, many of the known targets of the inhibitory miRs are not affected. Regions of strong homology to the seed sequences of these miRs were identified in the BART lncRNA. These findings suggest that the BART lncRNA functions as a sponge for growth-inhibitory miRs.
| S-EPMC9239068 | biostudies-literature
Project description:BACKGROUND:Burkitt lymphoma is an aggressive B-cell lymphoma presenting in three clinical forms: endemic, sporadic and immunodeficiency-associated. More than 90% of endemic Burkitt lymphoma carry latent Epstein-Barr virus, whereas only 20% of sporadic Burkitt lymphoma are associated with Epstein-Barr infection. Although the Epstein-Barr virus is highly related with the endemic form, how and whether the virus participates in its pathogenesis remains to be fully elucidated. In particular, the virus may impair cellular gene expression by its own encoded microRNAs. METHODS:Using microRNA profiling we compared Epstein-Barr-positive and Epstein-Barr-negative Burkitt lymphoma cases for both cellular and viral microRNAs. The array results were validated by qRT-PCR, and potential targets of viral microRNAs were then searched by bioinformatic predictions, and classified in functional categories, according to the Gene Ontology. Our findings were validated by in vitro functional studies and by immunohistochemistry on a larger series of cases. RESULTS:We showed that a few cellular microRNAs are differentially expressed between Epstein-Barr-positive and Epstein-Barr-negative Burkitt lymphoma cases, and identified a subset of viral microRNAs expressed in Epstein-Barr-positive Burkitt lymphomas. Of these, we characterized the effects of viral BART6-3p on regulation of cellular genes. In particular, we analyzed the IL-6 receptor genes (IL-6R? and IL-6ST), PTEN and WT1 expression for their possible relevance to Burkitt lymphoma. By means of immunohistochemistry, we observed a down-regulation of the IL-6 receptor and PTEN specifically in Epstein-Barr-positive Burkitt lymphoma cases, which may result in the impairment of key cellular pathways and may contribute to malignant transformation. On the contrary, no differences were observed between Epstein-Barr-positive and Epstein-Barr-negative Burkitt lymphoma cases for WT1 expression. CONCLUSIONS:Our preliminary results point at an active role for the Epstein-Barr virus in Burkitt lymphomagenesis and suggest new possible mechanisms used by the virus in determining dysregulation of the host cell physiology.
| S-EPMC4005456 | biostudies-literature
Project description:In Epstein-Barr Virus infected epithelial cancers, the alternatively spliced BamHI A rightward transcripts (BARTs) are abundantly expressed and are the template for two large clusters of miRNAs. This study indicates that both of these clusters independently can inhibit apoptosis in response to etoposide in an epithelial cell line. The Bcl-2 interacting mediator of cell death (Bim) was identified using gene expression microarrays and bioinformatic analysis indicated multiple potential binding sites for several BART miRNAs in the Bim 3'UTR. Bim protein was reduced by Cluster I and the individual expression of several miRNAs, while mRNA levels were unaffected. In reporter assays, the Bim 3' untranslated region (UTR) was inhibited by both clusters but not by any individual miRNAs. These results are consistent with the BART miRNAs downregulating Bim post-transcriptionally in part through the 3'UTR and suggest that there are miRNA recognition sites within other areas of the Bim mRNA.
| S-EPMC3340891 | biostudies-literature
Project description:Epstein-Barr virus (EBV) has evolved exquisite controls over its host cells, human B lymphocytes, not only directing these cells during latency to proliferate and thereby expand the pool of infected cells, but also to survive and thereby persist for the lifetime of the infected individual. Although these activities ensure the virus is successful, they also make the virus oncogenic, particularly when infected people are immunosuppressed. Here we show, strikingly, that one set of EBV's microRNAs (miRNAs) both sustain Burkitt's lymphoma (BL) cells in the absence of other viral oncogenes and promote the transformation of primary B lymphocytes. BL cells were engineered to lose EBV and found to die by apoptosis and could be rescued by constitutively expressing viral miRNAs in them. Two of these EBV miRNAs were found to target caspase 3 to inhibit apoptosis at physiological concentrations.
| S-EPMC3690170 | biostudies-literature
Project description:CST (BART BARF0) family viral RNAs are expressed in several types of Epstein-Barr virus (EBV) infection, including EBV-associated cancers. Many different spliced forms of these RNAs have been described; here we have clarified the structures of some of the more abundant splicing patterns. We report the first cDNAs representing a full-length CST mRNA from a clone library and further characterize the transcription start. The relative abundance of splicing patterns and genomic analysis of the open reading frames (ORFs) suggest that, in addition to the much studied BARF0 ORF, there may be important products made from some of the upstream ORFs in the CST RNAs. Potential biological functions are identified for two of these. The product of the RPMS1 ORF is shown to be a nuclear protein that can bind to the CBF1 component of Notch signal transduction. RPMS1 can inhibit the transcription activation induced through CBF1 by NotchIC or EBNA-2. The protein product of another CST ORF, A73, is shown to be a cytoplasmic protein which can interact with the cell RACK1 protein. Since RACK1 modulates signaling from protein kinase C and Src tyrosine kinases, the results suggest a possible role for CST products in growth control, perhaps consistent with the abundant transcription of CST RNAs in cancers such as nasopharyngeal carcinoma.
| S-EPMC111807 | biostudies-literature
Project description:Latent Epstein-Barr virus (EBV) infection is associated with several lymphoproliferative disorders, including posttransplant lymphoma, Hodgkin's disease, and Burkitt's lymphoma, as well as nasopharyngeal carcinoma (NPC). Twenty-nine microRNAs (miRNAs) have been identified that are transcribed during latent infection from three clusters in the EBV genome. Two of the three clusters of miRNAs are made from the BamHI A rightward transcripts (BARTs), a set of alternatively spliced transcripts that are highly abundant in NPC but have not been shown to produce a detectable protein. This study indicates that while the BART miRNAs are located in the first four introns of the transcripts, processing of the pre-miRNAs from the primary transcript occurs prior to completion of the splicing reaction. Additionally, production of the BART miRNAs correlates with accumulation of a spliced mRNA in which exon 1 is joined directly to exon 3, suggesting that this form of the transcript may favor production of miRNAs. Sequence variations and processing of pre-miRNAs to the mature form also may account for various differences in miRNA abundance. Importantly, residual intronic pieces that result from processing of the pre-miRNAs were detected in the nucleus. The predicted structures of these pieces suggest there is a bias or temporal pattern to the production of the individual pre-miRNAs. These findings indicate that multiple factors contribute to the production of the BART miRNAs and to the apparent differences in abundance between the individual miRNAs of the cluster.
| S-EPMC2546912 | biostudies-literature
Project description:Comprehensive Profiling of Epstein-Barr Virus-Encoded miRNAome Associated with Specific Latent Type in Tumor Cells Epstein-Barr virus (EBV) is an etiological cause of many human lymphocytic and epithelial malignancies. EBV expressed different genes associated with three latent types. So far as many as 44 EBV-encoded miRNA species have been found but their comprehensive and comparative profiling is not well documented in three latent infection states linked to various tumor cells. In this study, we utilized the polyA-tailed quantitative real time RT-PCR procedure to measure the relative abundance of viral miRNA species that linked to individual viral genome locations in combination with microarray evaluation in a subset of representative lymphoid and epithelial tumor cells undergoing various types of EBV latent infection. The results showed that miR-BHRF1 family and miR-BART family are expressed differentially in a tissue-dependent and latency-dependent manner. In particular, in NPC tissue and the only EBV consistently harboring cell line C666-1 with latency type II, there were highly abundant miR-BART family but not miR-BHRF1 family members that accounted for more than 10% of the whole known human miRNA library, implicating their important roles in maintaining EBV latent infection and driving NPC tumorigenesis. In addition, EBV miRNAome-based clustering analysis could classify three distinct EBV latency types, meanwhile, for the first time, we found and subsequently evaluated a novel secret latent switch in BL cell line Daudi from type I to III, which was unable to be identified by traditional latent biomarkers. Together, our data provided an in-depth and comparative profiling of EBV miRNA transcriptome in correspondence with three EBV latent infections, suggesting that different viral miRNA species were involved in divergent host cell carcinogenesis. Finally, EBV miRNAome, as a cluster of novel latency biomarkers expressed variedly in tumor cells, greatly complements and improves the classical typing criteria in conjunction with other latently expressed marker genes. 2 NPC tissue samples and 2 NPC cell lines and 5 lymphocytic cell lines
2012-07-06 | E-GEOD-33225 | biostudies-arrayexpress
Project description:Epstein-Barr virus (EBV) establishes lifelong latent infection in humans and is associated with several lymphoid and epithelial cancers. In nasopharyngeal carcinoma (NPC), EBV expresses few viral proteins but elevated levels of Bam-HI A rightward transcripts (BARTs) RNA, which includes viral microRNAs and long non-coding RNAs (lncRNAs). BART lncRNAs localize within the nucleus of EBV-infected cells and knockdown of BART lncRNAs significantly affects the expression of genes associated with cell adhesion, oxidoreductase activity, inflammation, and immunity. Notably, downregulation of IKAROS family zinc finger 3 (IKZF3/Aiolos), which plays a role in lymphocyte development and cell attachment, occurred in NPC C666-1 cells following BART lncRNA-knockdown. Since Aiolos expression is normally restricted to lymphoid cells and rarely observed in epithelial cells, induction of Aiolos by BART lncRNA was confirmed by expressing the major BART lncRNA isoform, RPMS1, in EBV-positive and -negative cells. BART lncRNA associated with the CBP/p300 complex and RNA polymerase II (Pol II) in the nucleus, suggesting that BART lncRNAs may mediate epigenetic regulation of gene expression through interaction with the chromatin remodeling machinery. This contention is further supported by evidence that BART lncRNA appears to stall Pol II at the promoter region and may regulate IFNB1 and CXCL8 expression by inhibiting transcription by Pol II in NPC. We hypothesize that EBV BART lncRNA expression modulates host gene expression and maintains EBV latency by interfering with histone methylation and acetylation processes. Aberrant expression of affected host genes mediated by BART lncRNA may lead to immune evasion, progression, and metastasis of NPC.
| S-EPMC6817499 | biostudies-literature
Project description:Comprehensive Profiling of Epstein-Barr Virus-Encoded miRNAome Associated with Specific Latent Type in Tumor Cells Epstein-Barr virus (EBV) is an etiological cause of many human lymphocytic and epithelial malignancies. EBV expressed different genes associated with three latent types. So far as many as 44 EBV-encoded miRNA species have been found but their comprehensive and comparative profiling is not well documented in three latent infection states linked to various tumor cells. In this study, we utilized the polyA-tailed quantitative real time RT-PCR procedure to measure the relative abundance of viral miRNA species that linked to individual viral genome locations in combination with microarray evaluation in a subset of representative lymphoid and epithelial tumor cells undergoing various types of EBV latent infection. The results showed that miR-BHRF1 family and miR-BART family are expressed differentially in a tissue-dependent and latency-dependent manner. In particular, in NPC tissue and the only EBV consistently harboring cell line C666-1 with latency type II, there were highly abundant miR-BART family but not miR-BHRF1 family members that accounted for more than 10% of the whole known human miRNA library, implicating their important roles in maintaining EBV latent infection and driving NPC tumorigenesis. In addition, EBV miRNAome-based clustering analysis could classify three distinct EBV latency types, meanwhile, for the first time, we found and subsequently evaluated a novel secret latent switch in BL cell line Daudi from type I to III, which was unable to be identified by traditional latent biomarkers. Together, our data provided an in-depth and comparative profiling of EBV miRNA transcriptome in correspondence with three EBV latent infections, suggesting that different viral miRNA species were involved in divergent host cell carcinogenesis. Finally, EBV miRNAome, as a cluster of novel latency biomarkers expressed variedly in tumor cells, greatly complements and improves the classical typing criteria in conjunction with other latently expressed marker genes.
2012-07-07 | GSE33225 | GEO
Project description:Epstein-Barr virus (EBV) encodes at least 25 pri-microRNAs (miRNAs) in two regions of its DNA genome, BART and BHRF. B95-8, an EBV reference strain, has a deletion in the BART region. However, no information is available on the deletions or mutations in the BART and BHRF regions in clinical samples of EBV-associated lymphoma.Nine DNA fragments encoding miR-BARTs and two coding miR-BHRF1s were amplified by PCR from DNA samples extracted from 16 cases of EBV-associated lymphoma. All the PCR products were sequenced directly. DNA fragments encoding miR-BARTs and miR-BHRF1-1 were successfully amplified from all samples. An adenine-to-guanine mutation in the DNA fragment encoding miR-BART2-3p was detected in four of the 16 cases, and a cytosine-to-thymidine mutation in the DNA fragment encoding miR-BART11-3p was detected in one of the 16 samples. These mutations were not associated with any histological categories of lymphoma. In conclusion, mutations were rarely observed in the DNA encoding viral miRNAs in cases of lymphoma. This suggests that the DNA sequences of EBV-encoded miR-BARTs and miR-BHRF1-1 are conserved in EBV-associated lymphoma.
| S-EPMC5513352 | biostudies-literature