Lower Levels of Survivin in Patients with Leukemic Low Grade B-Cell Lymphomas Expressing LMP1 Oncoprotein of Epstein-Barr Virus

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1560-1560
Author(s):  
Panagiotis Theodorou Diamantopoulos ◽  
Katerina Polonyphi ◽  
Maria Sofotasioiu ◽  
Athanassios Galanopoulos ◽  
Nikolaos Spanakis ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocytes ◽  
Epstein Barr Virus ◽  
Low Grade ◽  
B Cell Lymphomas ◽  
Barr Virus ◽  
Qrt Pcr ◽  
Epstein Barr ◽  
Rna Levels

Abstract Abstract 1560 Background Epstein-Barr virus (EBV) is a ubiquitous pathogen that chronically infects B lymphocytes and is implicated in the pathogenesis of lymphoproliferative diseases. Latent membrane protein 1 (LMP1), the major oncoprotein of the virus, has been shown to inhibit apoptosis and trigger survivin expression in malignant cell lines. Although EBV has not been implicated in the pathogenesis of low grade B-cell lymphomas, LMP1-mRNA has been detected in a significant proportion of patients with chronic lymphocytic leukemia (CLL). LMP1 is known for its antiapoptotic properties, but recent data show that LMP1 can simultaneously induce and inhibit apoptosis in B-cells. These opposite functions of LMP1 have not been studied in patients with low grade B-cell lymphomas. Objectives Our objectives were to detect LMP1-mRNA in patients with leukemic low grade B-cell lymphomas ant to investigate the postulated apoptotic properties of the protein, by correlating its expression to survivin levels. Patients and Methods Peripheral whole blood from 64 patients with leukemic low grade B-cell lymphomas was tested by qRT-PCR for the presence of BXLF-1 gene of EBV. The patients' characteristics are shown in table 1. All positive samples were tested by conventional PCR for LMP1-mRNA. Subsequently, survivin m-RNA levels were measured by qRT-PCR in all samples and compared between LMP1 positive and negative patients (Mann-Whitney U Test). Results The BXLF-1 gene was detected in 27/64 (42.1%) patients. LMP1-mRNA was detected in 23/64 (35.9%) patients and in 23/27 (85.2%) EBV-positive patients. Among CLL patients, LMP1-mRNA was detected in 19/44 (43.2%). Finally, surviving-mRNA levels were found to be 8.37 times higher in EBV-negative vs EBV-positive patients, (p=0.002) and 7.19 times higher in LMP1-negative vs LMP1-positive patients (p=0.009). The results are reported in detail in Table 1. Discussion Data from this year's studies suggest that LMP1 may exert both antiapoptotic and apoptotic functions. While the carboxy-terminal domain of LMP1 drives the proliferation and survival of EBV-infected B cells in vitro and in vivo, LMP1 may activate, through its amino-terminal six-transmembrane domains (6TM), the transmembrane receptor proteins PERK, ATF6 and IRE-1, leading to unfolded protein response (UPR) induction. UPR is a cellular stress response that promotes apoptosis. In different environments, LMP1 signaling may show differences regarding its apoptotic effects on B lymphocytes. In our study, we detected LMP1-mRNA in 43.2% of CLL patients, a proportion significantly higher than previously reported (14%). Moreover, for the first time, LMP1-mRNA was detected in patients with other than CLL low grade B-cell lymphomas (Table 1). In patients with leukemic low grade B-cell lymphomas, in the pathogenesis of which EBV is not causally implicated, LMP1 may have apoptotic instead of anti-apoptotic properties, as evidenced by the lower survivin m-RNA levels in LMP1-positive patients. This finding deserves further investigation, in order to reveal the clinical significance of the different functions of LMP1 in non-EBV related lymphomas. Disclosures: No relevant conflicts of interest to declare.

Transformation of Small B-Cell Lymphoma Into Large Cell CD30+, CD4+, Epstein-Barr Virus–Negative Lymphoma

2014 ◽  
Vol 138 (8) ◽  
pp. 1101-1105 ◽  
Author(s):  
Aaron C. Shaver ◽  
Ly Ma ◽  
Cindy Vnencak-Jones ◽  
Roland S. Schwarting ◽  
Kristina J. Fasig ◽  
...  
Keyword(s):  
B Cell ◽  
Epstein Barr Virus ◽  
Cell Lymphoma ◽  
Relevant Literature ◽  
B Cell Lymphoma ◽  
Low Grade ◽  
B Cell Lymphomas ◽  
Barr Virus ◽  
Wide Range ◽  
Epstein Barr

We report here 2 separate cases in which patients with known low-grade B-cell lymphomas presented with transformed lesions that were CD30+, CD4+, Epstein-Barr virus negative, and negative or focally weak for a wide range of B-cell, T-cell, and histiocytic/dendritic cell markers. In each case the transformed lymphoma possessed an identical pattern of immunoglobulin heavy chain and/or BCL2 rearrangement to the corresponding original low-grade B-cell lymphoma, confirming their identity as transformed B-cell lymphoma. A review of the relevant literature reveals that, to our knowledge, no transformed B-cell lymphomas with this immunophenotype have been previously reported, which creates the opportunity for potential errors of diagnosis. These cases highlight the importance of correlation with the patient's history and with molecular genetic results in rendering an accurate diagnosis.

scholarly journals Lytic Induction Therapy for Epstein-Barr Virus-Positive B-Cell Lymphomas

2004 ◽  
Vol 78 (4) ◽  
pp. 1893-1902 ◽  
Author(s):  
Wen-hai Feng ◽  
Gregory Hong ◽  
Henri-Jacques Delecluse ◽  
Shannon C. Kenney
Keyword(s):  
B Cells ◽  
B Cell ◽  
Epstein Barr Virus ◽  
Lymphoproliferative Disease ◽  
Immediate Early ◽  
B Cell Lymphomas ◽  
Lymphoblastoid Cells ◽  
Barr Virus ◽  
Ebv Infection ◽  
Epstein Barr

ABSTRACT A novel therapy for Epstein-Barr virus (EBV)-positive tumors involves the intentional induction of the lytic form of EBV infection combined with ganciclovir (GCV) treatment. Virally encoded kinases (thymidine kinase and BGLF4) which are expressed only during the lytic form of infection convert GCV (a nucleoside analogue) into its active, cytotoxic form. However, tightly latent EBV infection in B cells has made it difficult to identify drugs that can be used clinically to induce lytic viral infection in B-cell lymphomas. Here we demonstrate that gemcitabine and doxorubicin (but not 5-azacytidine, cis-platinum, or 5-fluorouracil) induce lytic EBV infection in EBV-transformed B cells in vitro and in vivo. Gemcitabine and doxorubicin both activated transcription from the promoters of the two viral immediate-early genes, BZLF1 and BRLF1, in EBV-negative B cells. This effect required the EGR-1 motif in the BRLF1 promoter and the CRE (ZII) and MEF-2D (ZI) binding sites in the BZLF1 promoter. GCV enhanced cell killing by gemcitabine or doxorubicin in lymphoblastoid cells transformed with wild-type EBV, but not in lymphoblastoid cells transformed by a mutant virus (with a deletion in the BZLF1 immediate-early gene) that is unable to enter the lytic form of infection. Most importantly, the combination of gemcitabine or doxorubicin and GCV was significantly more effective for the inhibition of EBV-driven lymphoproliferative disease in SCID mice than chemotherapy alone. In contrast, the combination of zidovudine and gemcitabine was no more effective than gemcitabine alone. These results suggest that the addition of GCV to either gemcitabine- or doxorubicin-containing chemotherapy regimens may enhance the therapeutic efficacy of these drugs for EBV-driven lymphoproliferative disease in patients.

scholarly journals Proteasomal Inhibition Triggers Viral Oncoprotein Degradation via Autophagy-Lysosomal Pathway

2019 ◽  
Author(s):  
Chandrima Gain ◽  
Samaresh Malik ◽  
Shaoni Bhattacharjee ◽  
Arijit Ghosh ◽  
Erle S. Robertson ◽  
...  
Keyword(s):  
B Cell ◽  
B Lymphocytes ◽  
Epstein Barr Virus ◽  
Viral Reactivation ◽  
B Cell Lymphomas ◽  
Viral Oncoprotein ◽  
Lytic Gene ◽  
Barr Virus ◽  
Proteasomal Inhibition ◽  
Epstein Barr

AbstractEpstein-Barr virus (EBV) nuclear oncoprotein EBNA3C is essential for B-cell transformation and development of several B-cell lymphomas particularly those are generated in an immuno-compromised background. EBNA3C recruits ubiquitin-proteasome machinery for deregulating multiple cellular oncoproteins and tumor suppressor proteins. Although EBNA3C is found to be ubiquitinated at its N-terminal region and interacts with 20S proteasome, the viral protein is surprisingly stable in growing B-lymphocytes. EBNA3C can also circumvent autophagy-lysosomal mediated protein degradation and subsequent antigen presentation for T-cell recognition. Recently, we have shown that EBNA3C enhances autophagy, which serve as a prerequisite for B-cell survival particularly under growth deprivation conditions. We now demonstrate that proteasomal inhibition by MG132 induces EBNA3C degradation both in EBV transformed B-lymphocytes and ectopic-expression systems. Interestingly, MG132 treatment promotes degradation of two EBNA3 family oncoproteins – EBNA3A and EBNA3C, but not the viral tumor suppressor protein EBNA3B. EBNA3C degradation induced by proteasomal inhibition is partially blocked when autophagy-lysosomal pathway is inhibited. In response to proteasomal inhibition, EBNA3C is predominantly K63-linked polyubiquitinated, colocalized with the autophagy-lsyosomal fraction in the cytoplasm and participated within p62-LC3B complex, which facilitates autophagy-mediated degradation. We further show that the degradation signal is present at the first 50 residues of the N-terminal region of EBNA3C. Proteasomal inhibition reduces the colony formation ability of this important viral oncoprotein, increases transcriptional activation of both latent and lytic gene expression and induces viral reactivation from EBV transformed B-lymphocytes. Altogether, this study offers rationale to use proteasome inhibitors as potential therapeutic strategy against multiple EBV associated B-cell lymphomas, where EBNA3C is expressed.Author SummaryEpstein-Barr virus (EBV) establishes latent infection in B-lymphocytes and is associated with a number of human malignancies, both of epithelial and lymphoid origin. EBV encoded EBNA3 family of nuclear latent antigens comprising of EBNA3A, EBNA3B, and EBNA3C are unique to immunoblastic lymphomas. While EBNA3A and EBNA3C are involved in blocking many important tumor suppressive mechanisms, EBNA3B exhibits tumor suppressive functions. Although EBNA3 proteins, in particular EBNA3C, interact with and employ different protein degradation machineries to induce B-cell lymphomagenesis, these viral proteins are extremely stable in growing B-lymphocytes. To this end, we now demonstrate that proteasomal inhibition leads to specifically degradation of oncogenic EBNA3A and EBNA3C proteins, whereas EBNA3B remains unaffected. Upon proteasomal inhibition, EBNA3C degradation occurs via autophagy-lysosomal pathway, through labeling with K63-linked polyubiquitination and participating in p62-LC3B complex involved in ubiquitin-mediated autophagy substrate selection and degradation through autolysosomal process. We also demonstrate that the N-terminal domain is responsible for autophgy-lysosomal mediated degradation, while the C-terminal domain plays a crucial role in cytoplasmic localization. Fascinatingly, while proteasomal inhibition reduces EBNA3C’s oncogenic property, it induces both latent and lytic gene expressions and promotes viral reactivation from EBV transformed B-lymphocytes. This is the first report which demonstrates a viral oncoprotein degrades through autophagy-lysosomal pathway upon proteasomal inhibition. In sum, the results promise development of novel strategies specifically targeting proteolytic pathway for the treatment of EBV associated B-cell lymphomas, particularly those are generated in immunocompromised individuals.

scholarly journals Epstein–Barr Virus Promotes B Cell Lymphomas by Manipulating the Host Epigenetic Machinery

Cancers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 3037 ◽  
Author(s):  
Andrea Di Pietro
Keyword(s):  
B Cells ◽  
B Cell ◽  
Epstein Barr Virus ◽  
Rapid Development ◽  
Tumour Suppressor Genes ◽  
B Cell Lymphomas ◽  
Barr Virus ◽  
Epigenetic Modifiers ◽  
Epigenetic Machinery ◽  
Epstein Barr

During the past decade, the rapid development of high-throughput next-generation sequencing technologies has significantly reinforced our understanding of the role of epigenetics in health and disease. Altered functions of epigenetic modifiers lead to the disruption of the host epigenome, ultimately inducing carcinogenesis and disease progression. Epstein–Barr virus (EBV) is an endemic herpesvirus that is associated with several malignant tumours, including B-cell related lymphomas. In EBV-infected cells, the epigenomic landscape is extensively reshaped by viral oncoproteins, which directly interact with epigenetic modifiers and modulate their function. This process is fundamental for the EBV life cycle, particularly for the establishment and maintenance of latency in B cells; however, the alteration of the host epigenetic machinery also contributes to the dysregulated expression of several cellular genes, including tumour suppressor genes, which can drive lymphoma development. This review outlines the molecular mechanisms underlying the epigenetic manipulation induced by EBV that lead to transformed B cells, as well as novel therapeutic interventions to target EBV-associated B-cell lymphomas.

scholarly journals Epstein-Barr Virus Induces Adhesion Receptor CD226 (DNAM-1) Expression during Primary B-Cell Transformation into Lymphoblastoid Cell Lines

mSphere ◽  
2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Lisa Grossman ◽  
Chris Chang ◽  
Joanne Dai ◽  
Pavel A. Nikitin ◽  
Dereje D. Jima ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Epstein Barr Virus ◽  
Human Herpesvirus ◽  
Barr Virus ◽  
Ebv Infection ◽  
Cellular Aggregation ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) is a common human herpesvirus that establishes latency in B cells. While EBV infection is asymptomatic for most individuals, immune-suppressed individuals are at significantly higher risk of a form of EBV latent infection in which infected B cells are reactivated, grow unchecked, and generate lymphomas. This form of latency is modeled in the laboratory by infecting B cells from the blood of normal human donors in vitro. In this model, we identified a protein called CD226 that is induced by EBV but is not normally expressed on B cells. Rather, it is known to play a role in aggregation and survival signaling of non-B cells in the immune system. Cultures of EBV-infected cells adhere to one another in “clumps,” and while the proteins that are responsible for this cellular aggregation are not fully understood, we hypothesized that this form of cellular aggregation may provide a survival advantage. In this article, we characterize the mechanism by which EBV induces this protein and its expression on lymphoma tissue and cell lines and characterize EBV-infected cell lines in which CD226 has been knocked out. Epstein-Barr virus (EBV), an oncogenic herpesvirus, infects and transforms primary B cells into immortal lymphoblastoid cell lines (LCLs), providing a model for EBV-mediated tumorigenesis. EBV transformation stimulates robust homotypic aggregation, indicating that EBV induces molecules that mediate cell-cell adhesion. We report that EBV potently induced expression of the adhesion molecule CD226, which is not normally expressed on B cells. We found that early after infection of primary B cells, EBV promoted an increase in CD226 mRNA and protein expression. CD226 levels increased further from early proliferating EBV-positive B cells to LCLs. We found that CD226 expression on B cells was independent of B-cell activation as CpG DNA failed to induce CD226 to the extent of EBV infection. CD226 expression was high in EBV-infected B cells expressing the latency III growth program, but low in EBV-negative and EBV latency I-infected B-lymphoma cell lines. We validated this correlation by demonstrating that the latency III characteristic EBV NF-κB activator, latent membrane protein 1 (LMP1), was sufficient for CD226 upregulation and that CD226 was more highly expressed in lymphomas with increased NF-κB activity. Finally, we found that CD226 was not important for LCL steady-state growth, survival in response to apoptotic stress, homotypic aggregation, or adhesion to activated endothelial cells. These findings collectively suggest that EBV induces expression of a cell adhesion molecule on primary B cells that may play a role in the tumor microenvironment of EBV-associated B-cell malignancies or facilitate adhesion in the establishment of latency in vivo. IMPORTANCE Epstein-Barr virus (EBV) is a common human herpesvirus that establishes latency in B cells. While EBV infection is asymptomatic for most individuals, immune-suppressed individuals are at significantly higher risk of a form of EBV latent infection in which infected B cells are reactivated, grow unchecked, and generate lymphomas. This form of latency is modeled in the laboratory by infecting B cells from the blood of normal human donors in vitro. In this model, we identified a protein called CD226 that is induced by EBV but is not normally expressed on B cells. Rather, it is known to play a role in aggregation and survival signaling of non-B cells in the immune system. Cultures of EBV-infected cells adhere to one another in “clumps,” and while the proteins that are responsible for this cellular aggregation are not fully understood, we hypothesized that this form of cellular aggregation may provide a survival advantage. In this article, we characterize the mechanism by which EBV induces this protein and its expression on lymphoma tissue and cell lines and characterize EBV-infected cell lines in which CD226 has been knocked out.

scholarly journals Lactic Acid Downregulates Viral MicroRNA To Promote Epstein-Barr Virus-Immortalized B Lymphoblastic Cell Adhesion and Growth

2018 ◽  
Vol 92 (9) ◽  
Author(s):  
Xiaohui Mo ◽  
Fang Wei ◽  
Yin Tong ◽  
Ling Ding ◽  
Qing Zhu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Cell Adhesion ◽  
B Cells ◽  
B Cell ◽  
Cancer Progression ◽  
Epstein Barr Virus ◽  
Lactate Production ◽  
Barr Virus ◽  
Viral Microrna ◽  
Epstein Barr

ABSTRACT High plasma lactate is associated with poor prognosis of many malignancies, but its role in virally mediated cancer progression and underlying molecular mechanisms are unclear. Epstein-Barr virus (EBV), the first human oncogenic virus, causes several cancers, including B-cell lymphoma. Here, we report that lactate dehydrogenase A (LDH-A) expression and lactate production are elevated in EBV-immortalized B lymphoblastic cells, and lactic acid (LA; acidic lactate) at low concentration triggers EBV-infected B-cell adhesion, morphological changes, and proliferation in vitro and in vivo . Moreover, LA-induced responses of EBV-infected B cells uniquely occurs in viral latency type III, and it is dramatically associated with the inhibition of global viral microRNAs, particularly the miR-BHRF1 cluster, and the high expression of SMAD3 , JUN , and COL1A genes. The introduction of miR-BHRF1-1 blocks the LA-induced effects of EBV-infected B cells. Thus, this may be a novel mechanism to explain EBV-immortalized B lymphoblastic cell malignancy in an LA microenvironment. IMPORTANCE The tumor microenvironment is complicated, and lactate, which is created by cell metabolism, contributes to an acidic microenvironment that facilitates cancer progression. However, how LA operates in virus-associated cancers is unclear. Thus, we studied how EBV (the first tumor virus identified in humans; it is associated with many cancers) upregulates the expression of LDH-A and lactate production in B lymphoma cells. Elevated LA induces adhesion and the growth of EBV-infected B cells by inhibiting viral microRNA transcription. Thus, we offer a novel understanding of how EBV utilizes an acidic microenvironment to promote cancer development.

scholarly journals Rewiring of B cell receptor signaling by Epstein–Barr virus LMP2A

2020 ◽  
Vol 117 (42) ◽  
pp. 26318-26327
Author(s):  
Kamonwan Fish ◽  
Federico Comoglio ◽  
Arthur L. Shaffer ◽  
Yanlong Ji ◽  
Kuan-Ting Pan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
B Cells ◽  
B Cell ◽  
Epstein Barr Virus ◽  
Cell Receptor ◽  
B Cell Receptor ◽  
Barr Virus ◽  
Human B Cells ◽  
Bcr Signaling ◽  
Epstein Barr

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 comparing LMP2A and BCR signaling in primary human B cells using phosphoproteomics and transcriptome profiling, we identified molecular mechanisms through which LMP2A affects B cell biology. Consistent with the 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, and PLCγ2, and its downstream transcription factor NFAT. However, the 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 nuclear factor κB (NF-κB) 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 1 (RB1). LMP2A cooperated with MYC and mutant cyclin D3, two oncogenic drivers of Burkitt lymphoma, to promote proliferation and survival of primary human B cells by counteracting MYC-induced apoptosis and by inhibiting RB1 function, thereby promoting cell-cycle progression. Our results indicate that LMP2A is not a pure BCR mimic but rather rewires intracellular signaling in EBV-infected B cells that optimizes cell survival and proliferation, setting the stage for oncogenic transformation.

Sign in / Sign up

Export Citation Format

Share Document