Large-scale hypomethylated blocks associated with Epstein-Barr virus-induced B-cell immortalization
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE49629 | GEO | 2013/09/17
SECONDARY ACCESSION(S): PRJNA214514
REPOSITORIES: GEO
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Project description:Altered DNA methylation occurs ubiquitously in human cancer from the earliest measurable stages. A cogent approach to understanding the mechanism and timing of altered DNA methylation is to analyze it in the context of carcinogenesis by a defined agent. Epstein-Barr virus (EBV) is a human oncogenic herpesvirus associated with lymphoma and nasopharyngeal carcinoma, but also used commonly in the laboratory to immortalize human B-cells in culture. Here we have performed whole-genome bisulfite sequencing of normal B-cells, activated B-cells, and EBV-immortalized B-cells from the same three individuals, in order to identify the impact of transformation on the methylome. Surprisingly, large-scale hypomethylated blocks comprising two-thirds of the genome were induced by EBV immortalization but not by B-cell activation per se. These regions largely corresponded to hypomethylated blocks that we have observed in human cancer, and they were associated with gene-expression hypervariability, similar to human cancer, and consistent with a model of epigenomic change promoting tumor cell heterogeneity. We also describe small-scale changes in DNA methylation near CpG islands. These results suggest that methylation disruption is an early and critical step in malignant transformation.
| S-EPMC3912409 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2013-09-17 | E-GEOD-49629 | biostudies-arrayexpress
Project description:To determine what DNA methylation and gene expression changes occur following EBV transformation. B-cells were isolated from 3 donors. Resting, CD40 activated and EBV transfromed cells from each donor was analyzed. Each sample was assayed using Affymetrix expression arrays and whole genome bisulfite sequenicng. Additional time points during transformation and activation were sequenced as well, but not assayed for expression.
2013-09-17 | GSE49627 | GEO
Project description:To determine what DNA methylation and gene expression changes occur following EBV transformation. B-cells were isolated from 3 donors. Resting, CD40 activated and EBV transfromed cells from each donor was analyzed. Each sample was assayed using Affymetrix expression arrays and whole genome bisulfite sequenicng. Additional time points during transformation and activation were sequenced as well, but not assayed for expression. B-cells were isolated from 3 donors. Resting, CD40 activated and EBV transfromed cells from each donor was analyzed.
2013-09-17 | E-GEOD-49628 | biostudies-arrayexpress
Project description:To determine what DNA methylation and gene expression changes occur following EBV transformation. B-cells were isolated from 3 donors. Resting, CD40 activated and EBV transfromed cells from each donor was analyzed. Each sample was assayed using Affymetrix expression arrays and whole genome bisulfite sequenicng. Additional time points during transformation and activation were sequenced as well, but not assayed for expression. B-cells were isolated from 3 donors. Resting, CD40 activated and EBV transfromed cells from each donor was analyzed. Additional B-cells were isolated from 2 additional donors and assay at days 16 and week 3 following CD40 activation and EBV infection. Only one donor contributed to the EBV timepoints.
2013-09-17 | E-GEOD-49627 | biostudies-arrayexpress
Project description:To determine what DNA methylation and gene expression changes occur following EBV transformation. B-cells were isolated from 3 donors. Resting, CD40 activated and EBV transfromed cells from each donor was analyzed. Each sample was assayed using Affymetrix expression arrays and whole genome bisulfite sequenicng. Additional time points during transformation and activation were sequenced as well, but not assayed for expression.
2013-09-17 | GSE49628 | GEO
Project description:BackgroundEpstein-Barr virus (EBV) causes a variety of clinical manifestations from asymptomatic infection to acute infectious mononucleosis in human. Moreover, the EBV infection is associated with malignancies. The large-scale EBV seroepidemiology across all age groups has been lacking in Taiwan.MethodsA total of 1411 serum samples were tested to examine the seroprevalence of EBV in 2007. The samples were collected during an island-wide seroepidemiological survey of vaccine preventable diseases in Taiwan. The enzyme-linked immunosorbent assay was performed to detect anti-EBV viral capsid IgG in sera. Demographic and personal health data were obtained by questionnaires.ResultsThe overall weighted seropositive rate of EBV was 88.5% (95% CI, 86.7%-90.1%). The seropositive rate of EBV reached 52.8% (95% CI, 44.0%-61.6%) in children aged 2 years, rapidly rose to 88.7% (95% CI, 79.0%-95.1%) in those aged 5-7 years and 93.0% (95%CI, 83.0%-98.1%) for those aged 14-16 years. Age and higher educational level were associated with the increased EBV seropositive rate.ConclusionIn Taiwan, people had the EBV infection early in life. Children under 7 years should be the primary target popution of public health measures in the future.
| S-EPMC4304788 | biostudies-literature
Project description:Activation of cellular oncogenes as well as infection with tumor viruses can promote aberrant proliferation and activation of the host DNA damage response. Epstein-Barr virus (EBV) infection of primary human B cells induces a transient period of hyper-proliferation, but many of these infected cells succumb to an ataxia telangiectasia mutated/checkpoint kinase 2 (ATM/Chk2)-mediated senescence-like growth arrest. In this study, we assessed the role of DNA replicative stress and nucleotide pool levels in limiting EBV-infected B-cell outgrowth. We found that EBV triggered activation of the ataxia telangiectasia and Rad3-related (ATR) signaling pathway in the early rapidly proliferating cells, which were also significantly more sensitive to inhibition of the ATR pathway than late attenuated proliferating cells. Through nuclear halo assays, we determined that early EBV-infected cells displayed increased replicative stress and DNA damage relative to late proliferating cells. Finally, we found that early after infection, hyper-proliferating B cells exhibited limited deoxyribonucleotide triphosphate (dNTP) pools compared with late proliferating and EBV-immortalized lymphoblastoid cell lines with a specific loss of purine dNTPs. Importantly, supplementation with exogenous nucleosides before the period of hyper-proliferation markedly enhanced B-cell immortalization by EBV and rescued replicative stress. Together our results suggest that purine dNTP biosynthesis has a critical role in the early stages of EBV-mediated B-cell immortalization.
| S-EPMC5519195 | biostudies-literature
Project description:Epstein-Barr virus (EBV) is an oncogenic herpesvirus that has been causally linked to the development of B-cell and epithelial malignancies. Early after infection, EBV induces a transient period of hyperproliferation that is suppressed by the activation of the DNA damage response and a G1/S-phase growth arrest. This growth arrest prevents long-term outgrowth of the majority of infected cells. We developed a method to isolate and characterize infected cells that arrest after this early burst of proliferation and integrated gene expression and metabolic profiling to gain a better understanding of the pathways that attenuate immortalization. We found that the arrested cells have a reduced level of mitochondrial respiration and a decrease in the expression of genes involved in the TCA cycle and oxidative phosphorylation. Indeed, the growth arrest in early infected cells could be rescued by supplementing the TCA cycle. Arrested cells were characterized by an increase in the expression of p53 pathway gene targets, including sestrins leading to activation of AMPK, a reduction in mTOR signaling, and, consequently, elevated autophagy that was important for cell survival. Autophagy was also critical to maintain early hyperproliferation during metabolic stress. Finally, in assessing the metabolic changes from early infection to long-term outgrowth, we found concomitant increases in glucose import and surface glucose transporter 1 (GLUT1) levels, leading to elevated glycolysis, oxidative phosphorylation, and suppression of basal autophagy. Our study demonstrates that oncogene-induced senescence triggered by a combination of metabolic and genotoxic stress acts as an intrinsic barrier to EBV-mediated transformation.
| S-EPMC4760815 | biostudies-literature
Project description:Epstein-Barr virus (EBV), originally discovered through its association with Burkitt lymphoma, is now aetiologically linked to a remarkably wide range of lymphoproliferative lesions and malignant lymphomas of B-, T- and NK-cell origin. Some occur as rare accidents of virus persistence in the B lymphoid system, while others arise as a result of viral entry into unnatural target cells. The early finding that EBV is a potent B-cell growth transforming agent hinted at a simple oncogenic mechanism by which this virus could promote lymphomagenesis. In reality, the pathogenesis of EBV-associated lymphomas involves a complex interplay between different patterns of viral gene expression and cellular genetic changes. Here we review recent developments in our understanding of EBV-associated lymphomagenesis in both the immunocompetent and immunocompromised host.This article is part of the themed issue 'Human oncogenic viruses'.
| S-EPMC5597738 | biostudies-literature