EBV-associated Tumors Research Articles

The novel immune landscape of immune-checkpoint blockade in EBV-associated malignancies.

The Epstein-Barr virus (EBV) is a ubiquitous gamma-herpesvirus and a class 1 carcinogen that is closely associated with a series of malignant lymphomas and epithelial cell carcinomas. Although these EBV-related cancers may exhibit different features in clinical symptoms and anatomical sites, they all have a characteristic immune-suppressed tumor immune microenvironment (TIME) that is tightly correlated with an abundance of tumor-infiltrating lymphocytes (TILs) that primarily result from the EBV infection. Overwhelming evidence indicates that an upregulation of immune-checkpoint molecules is a powerful strategy employed by the EBV to escape immune surveillance. While previous studies have mainly focused on the therapeutic effects of PD-1 and CTLA-4 blockades in treating EBV-associated tumors, several novel inhibitory receptors (e.g., CD47, LAG-3, TIM-3, VISTA, and DDR1) have recently been identified as potential targets for treating EBV-associated malignancies (EBVaMs). This review retrospectively summarizes the biological mechanisms used for immune checkpoint evasion in EBV-associated tumors. Its purpose is to update our current knowledge concerning the underlying mechanisms by which an immune checkpoint blockade triggers host antitumor immunity against EBVaMs. Additionally, this review may help investigators to more fully understand the correlation between EBV infection and tumor development and subsequently develop novel therapeutic strategies.

Epidemiology and treatment outcome of nasopharyngeal carcinoma in a low-incidence population - a DAHANCA analysis in Denmark 2000-2018.

Nasopharyngeal carcinoma (NPC) is a rare disease and most studies have therefore been conducted in endemic areas. The aim of this study was to describe epidemiology and treatment outcomes of NPC in a population-based, non-endemic setting. Patients with NPC diagnosed in Denmark from 2000 to 2018 were identified in the Danish Head and Neck Cancer Study Group (DAHANCA) database. Clinical records were reviewed to obtain missing data and confirm outcome, histological subtypes, Epstein-Barr virus (EBV)-status, prognostic factors, and treatment. NPC was identified in 394 patients corresponding to age-standardized incidence rates of 0.5 and 0.2 per 100,000 in men and women, respectively. The 5-year overall (OS) and disease-specific survival (DSS) were 56 and 66%. In multivariate analysis, stage, smoking, and histology affected both OS and DSS, as patients with undifferentiated carcinomas had superior outcomes. Tumor EBV-status was determined in 221 patients, of whom 160 (72%) tested positive. EBV-positivity was associated with an improved OS in univariate analysis, but not after adjustment for relevant clinical factors. NPC is a rare malignancy in Denmark, and three in four patients have EBV-associated tumors. Tumor histology, smoking status, and stage, but not EBV-status, had independent prognostic impact on survival.

Epstein-Barr Virus-Associated Smooth Muscle Tumor After Kidney Transplantation: A French Multicenter Retrospective Study.

Epstein-Barr virus (EBV) is a herpesvirus linked to nine different human tumors and lymphoproliferative disorders. Immunosuppression promotes EBV-driven malignancies. The most frequent EBV-induced malignancies are lymphomas and nasopharyngeal carcinoma. By promoting smooth muscle proliferation, EBV can induce EBV-associated smooth muscle tumors (EBV-SMT). EBV-SMT is a rare oncological entity for which no current guideline for diagnosis or management exists. Data on posttransplant EBV-SMT (PT-SMT) are scarce in kidney transplant recipients. We conducted a national multicentric retrospective study and collected cases among transplantation centers in France. Kidney transplant recipients experiencing histologically proven PT-SMT were included. We collected data on demographic characteristics of patient, history of kidney transplantation, history of PT-SMT, evolution of graft function, and patient survival. Eight patients were included. The median age at PT-SMT diagnosis was 31 years (range 6.5-40). PT-SMT occurred after a median delay of 37.8 months after transplantation (range 6-175). PT-SMT management consisted in immunosuppressive regimen minimization in all patients. Introduction of mTOR inhibitors was performed in two patients. Four patients (50%) needed chemotherapy. Surgical resection was performed in four patients. At last follow-up after PT-SMT diagnosis (median 33 months (range 17-132)), five patients were considered in complete remission, and two patients had died. Two patients experienced graft rejection; two resumed dialysis (25%). All patients with available data presented with impaired graft function at last follow-up. PT-SMT is a subacute and progressive disease during kidney transplantation. Even if the risk of developing PT-SMT is low in kidney transplant recipients (0.07% in our cohort), PT-SMT is associated with significant graft loss, possibly due to reduced immunosuppression. Developing guidelines could help transplantation teams better manage these patients.

The Emerging Role of Ferroptosis in EBV-Associated Cancer: Implications for Cancer Therapy.

Ferroptosis is a novel and iron-dependent form of programmed cell death, which has been implicated in the pathogenesis of various human cancers. EBV is a well-recognized oncogenic virus that controls multiple signaling pathways within the host cell, including ferroptosis signaling. Recent studies show that inducing ferroptosis could be an efficient therapeutic strategy for EBV-associated tumors. This review will firstly describe the mechanism of ferroptosis, then summarize EBV infection and EBV-associated tumors, as well as the crosstalk between EBV infection and the ferroptosis signaling pathway, and finally discuss the role and potential application of ferroptosis-related reagents in EBV-associated tumors.

EBV promotes TCR-T-cell therapy resistance by inducing CD163+M2 macrophage polarization and MMP9 secretion

BackgroundEpstein-Barr virus (EBV) is a double-stranded DNA oncogenic virus. Several types of solid tumors, such as nasopharyngeal carcinoma, EBV-associated gastric carcinoma, and lymphoepithelioma-like carcinoma of the lung, have been linked...

Epstein-Barr Virus Latent Membrane Protein 2A (LMP2A) Enhances ATP Production in B Cell Tumors through mTOR and HIF-1α.

Epstein-Barr Virus (EBV) exists in a latent state in 90% of the world's population and is linked to numerous cancers, such as Burkitt's Lymphoma, Hodgkin's, and non-Hodgkin's Lymphoma. One EBV latency protein, latency membrane protein 2A (LMP2A), is expressed in multiple latency phenotypes. LMP2A signaling has been extensively studied and one target of LMP2A is the mammalian target of rapamycin (mTOR). Since mTOR has been linked to reprogramming tumor metabolism and increasing levels of hypoxia-inducible factor 1 α (HIF-1α), we hypothesized that LMP2A would increase HIF-1α levels to enhance ATP generation in B lymphoma cell lines. Our data indicate that LMP2A increases ATP generation in multiple Burkitt lymphoma cell lines that were dependent on HIF-1α. Subsequent studies indicate that the addition of the mTOR inhibitor, rapamycin, blocked the LMP2A-dependent increase in HIF-1α. Further studies demonstrate that LMP2A does not increase HIF-1α levels by increasing HIF-1α RNA or STAT3 activation. In contrast, LMP2A and mTOR-dependent increase in HIF-1α required mTOR-dependent phosphorylation of p70 S6 Kinase and 4E-BP1. These findings implicate the importance of LMP2A in promoting B cell lymphoma survival by increasing ATP generation and identifying potential pharmaceutical targets to treat EBV-associated tumors.

Abstract 465: Effect of Epstein-Barr virus lnc-BARTs on EBV genome maintenance in EBV-associated tumors

Abstract Most humans infected with Epstein-Barr virus (EBV) remain asymptomatic throughout the whole life. However, EBV is linked to several human cancers, including Burkitt's lymphoma, Hodgkin's disease, post-transplant lymphoproliferative disorder (PTLD), nasopharyngeal carcinoma (NPC), and gastric carcinoma. Among these EBV-associated tumors, EBV genome is present in 100% of NPC tumor cells. In NPC cells, EBV establishes a latent infection, expressing limited number of viral proteins but elevated levels of non-coding RNAs transcribed from the BamHI-A region of the EBV genome, also known as BamHI-A rightward transcripts (BARTs). The family of EBV BART RNAs includes BART-microRNAs (miRNAs) and long non-coding RNAs (lnc-BARTs). Although various functions of BART miRNAs have been identified, the role of EBV lnc-BARTs remains largely unknown. In this study, we provide evidence demonstrating that lnc-BARTs functions as a regulatory long non-coding RNA, referred to as lnc-BARTs. These lnc-BARTs play keys role in modulating the core networks that maintains EBV latency and promotes NPC oncogenesis through epigenetic mechanisms. Our study found that the apoptosis rate of NPC cells is significantly increased following the knockdown of EBV lnc-BARTs, indicating their anti-apoptotic role in EBV-associated tumors. Mass spectrometry analysis identified several host factors, including transcriptional regulators BRD4 and SC35’ interact with EBV lnc-BARTs in NPC cells. RNA-FISH assays showed lnc-BARTs co-localized with BRD4 and SC35 complexes in nuclear s peckles and such interaction were disrupted by JQ1, a BRD4 competitive inhibitor. Binding of lnc-BARTs to BRD4 RNA was confirmed using immunoprecipitation and pulldown assays. ATAC sequencing and transcriptome analyses showed that BART knockdown in EBV-harboring NPC cell line C666-1 led to reduced chromatin accessibility, downregulation of oncogenes, and decreased EBV episome replication and maintenance. Quantitative qPCR and DNA FISH analyses of cell samples treated with shRNA targeting lnc-BARTs or BRD4 reduced EBV copy numbers and EBNA1 RNA expression levels in EBV-infected NPC cells. Finally, ChIP sequencing analysis revealed that lnc-BARTs is critical for BRD4 binding to the oriP region of the EBV genome. These findings support a mechanism by which EBV lnc-BARTs epigenetically regulate host gene expression through functional interactions with elongation regulatory machinery and contribute to the maintenance of EBV latent genome by interaction with BRD4 complex. Citation Format: Jiayan Liu, Bobo Wing-Yee Mok, Honglin Chen. Effect of Epstein-Barr virus lnc-BARTs on EBV genome maintenance in EBV-associated tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 465.

Abstract 7001: Profiling the CpG methylation patterns of Epstein-Barr virus DNA in lymphoma patients from Ethiopia

Abstract Introduction: Epstein-Barr virus (EBV) is a tumor virus associated with various malignancies, driven by genetic mutations and epigenetic alterations, including DNA methylation. Abnormal CpG methylation holds promise as a diagnostic and therapeutic biomarker for EBV-associated tumors. However, the understanding of EBV's epigenetic mechanisms remain limited. Determining the methylation profile of EBV is crucial for gaining insights into the pathogenesis of EBV-associated tumors, developing diagnostic biomarkers, and exploring potential therapeutic strategies. Therefore, our study aimed to assess the CpG methylation profile of EBV DNA in lymphoma patients from Ethiopia. Methods: This study enrolled 115 lymphoma patients from Tikur Anbessa Specialized Hospital in Addis Ababa, Ethiopia. Plasma and formalin-fixed paraffin-embedded blocks were collected from the participants, and isolation of DNA was performed from these samples. The methylation analysis was performed using the methylation-iPLEX assay. iPLEX capture and extension primers were designed to amplify and target EBV CpGs from bisulfite-converted DNA sequences. Ethical approval was also obtained from respected institutions. Results: Among the 115 participants, 65.2% (n = 75) were male patients. The largest proportion (n = 35, 30.4%) fell within the 41-60 age group. Non-Hodgkin lymphoma (NHL) was diagnosed in 96 patients, while 19 had Hodgkin lymphoma (HL). In the NHL group, the majority (n = 27, 28.1%) were classified as diffuse large cell lymphoma, followed by follicular lymphoma (n = 24, 25%). Out of the different EBV genome methylation sites, we have identified 24 EBV genes to assess the methylation status of the EBV genome. Average methylation levels of these genes were ranged from 45% to 50%. Notably, the HL group exhibited significant heterogeneity in methylation levels, while the CpG methylation status of EBV genes in NHL subtypes demonstrated a consistent pattern. A significant proportion of our samples exhibited methylation loss in the lytic gene BZLF1 and at the origin of replication associated with lytic replication. Conclusions: This study presents the first data from East Africa, shedding light on the EBV DNA methylation status in a diverse group of lymphoma patients. Further investigations in different locations are necessary to elucidate the impact of EBV DNA methylation on tumor progression. Citation Format: Seifegebriel T. Feleke, Kidist Z. Shita, Abdulaziz A. Sherif, Fisihatsion T. Woldegebriel, Christoph Weigel, Elshafa H. Ahmed, Tamrat A. Zeleke, Robert A. Baiocchi. Profiling the CpG methylation patterns of Epstein-Barr virus DNA in lymphoma patients from Ethiopia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7001.

EBV DNA methylation profiles and its application in distinguishing nasopharyngeal carcinoma and nasal NK/T-cell lymphoma

BackgroundAs an oncovirus, EBV is associated with multiple cancers, including solid tumors and hematological malignancies. EBV methylation plays an important role in regulating tumor occurrence. However, the EBV methylation profiles in EBV-associated tumor tissues are poorly understood.ResultsIn this study, EBV methylation capture sequencing was conducted in several different tumor tissue samples, including NPC, EBVaGC, lung LELC and parotid LELC. Besides, EBV capture sequencing and following qMSP were performed on nasopharyngeal brushing samples from NPC and nasal NKTCL patients. Our results showed that the EBV genome among different types of tumors displayed specific methylation patterns. Among the four types of tumors from epithelial origin (NPC, EBVaGC, lung LELC and parotid LELC), the most significant differences were found between EBVaGC and the others. For example, in EBVaGC, all CpG sites within 1,44,189–1,45,136 bp of the EBV genome sequence on gene RPMS1 were hyper-methylated compared to the others. Differently, significant differences of EBV CpG sites, particularly those located on gene BILF2, were observed between NPC and nasal NKTCL patients in nasopharyngeal brushing samples. Further, the methylated level of BILF2 was further detected using qMSP, and a diagnostic model distinguishing NPC and nasal NKTCL was established. The AUC of the model was 0.9801 (95% CI 0.9524–1.0000), with the sensitivity and specificity of 98.81% (95% CI 93.63–99.94%) and 76.92% (95% CI 49.74–91.82%), respectively.ConclusionsOur study reveals more clues for further understanding the pathogenesis of EBV, and provides a possibility for distinguishing EBV-related tumor by detecting specific EBV CpG sites.

EBV-Associated Smooth Muscle Tumors With Autoimmune Hemolytic Anemia and Hepatitis B Infection: Report of a Previously Undescribed Neoplasm With Review.

Epstein-Barr virus-associated smooth muscle tumor (EBV-SMT) is rare in adults. The presence of intratumoral T lymphocytes and primitive rounded cells characterized this neoplasm. We report a 24-year-old Chinese man who developed EBV-SMT in the right adrenal gland with hepatitis B infection and autoimmune hemolytic anemia without a history of HIV infection, primary immune deficiency, organ transplantation, or malignant tumor. This patient had an unknown immunodeficient state. EBV-SMTs are commonly located in the liver, lung, and gastrointestinal tract but rarely in the adrenal gland. We reviewed 10 reported literature on EBV-SMT in the adrenal gland. It is imperative to distinguish EBV-SMT from conventional somatic smooth muscle tumors. The discovery of EBV-SMT forces the clinician to conduct a thorough evaluation of immune function and immune status surveillance, and these patients are vulnerable to subsequent malignant tumors.

Les marqueurs virologiques des cancers associés au virus d’Epstein-Barr

AbstractEpstein-Barr virus is the first human virus related to human cancer and is currently associated with at least ten cancers mainly arisen from B or T lymphocytes or from epithelial cells. EBV-associated tumors are responsible for 1,8 % of all cancer-related deaths worldwide. The routinely detection in biopsy tissues of non coding RNA EBERs (EBv-Encoded small RNA) by in situ hybridization assay remains the hallmark of all EBV-associated malignancies. The EBV-associated cancers are also characterized by abnormal EBV DNA viral load in whole blood or plasma and atypical serological profiles (IgG/IgA against VCA, Viral Capsid Antigen ; EA Early Antigen ; EBNA1 Epstein-Barr Nuclear Antigen 1 ). The analysis of these virological biomarkers are recommended for the screening, diagnosis or the therapeutic follow up of patients at high risk of post transplant lymphoproliferative disease, patients with nasopharyngeal carcinoma and EBV associated T/NK lymphoma. Their clinical usefulness in Hodgkin lymphoma and gastric carcinoma is likely but less established.

A Clinicopathology Review and Update of Epstein–Barr Virus-Associated Mesenchymal Tumors

The Epstein–Barr virus (EBV) is associated with various tumor types, including nasopharyngeal carcinoma and lymphoproliferative disorders. While much is known about EBV-related epithelial and lymphoid tumors, there is a paucity of knowledge concerning EBV-associated mesenchymal tumors. This review aims to provide a comprehensive overview of EBV-associated mesenchymal tumors, encompassing their clinical features, pathological characteristics, pathophysiology, prognostic factors, and current treatment approaches. Through an extensive literature search using the PubMed database, we were able to identify three distinct EBV-associated mesenchymal tumors: EBV-associated smooth muscle tumors, inflammatory pseudotumor-like follicular dendritic cell sarcomas, and EBV-associated osteosarcomas. Although this review extensively explored the different aspects of these mesenchymal tumors, our comprehension of the underlying pathophysiology in this context is still incomplete. Therefore, we hope that this review paper will not only serve as a valuable repository of information but also serve as a catalyst for prospective in vitro and in vivo research studies to bridge the existing knowledge gap surrounding pathophysiology, ultimately making an important contribution to shaping future therapeutic approaches.

EBV-encoded miRNAs BHRF1-1 and BART2-5p aggravate post- transplant lymphoproliferative disorder via LZTS2-PI3K-AKT axis

Post-transplant lymphoproliferative disorder (PTLD) is one of the most serious complications after transplantation. Epstein-Barr virus (EBV) is a key pathogenic driver of PTLD. About 80% of PTLD patients are EBV positive. However, the accuracy of preventing and diagnosing EBV-PTLD by monitoring EBV DNA load is limited. Therefore, new diagnostic molecular markers are urgently needed. EBV-encoded miRNAs can regulate a variety of EBV-associated tumors and are expected to be potential diagnostic markers and therapeutic targets. We found BHRF1-1 and BART2-5p were significantly elevated in EBV-PTLD patients, functionally promoting proliferation and inhibiting apoptosis in EBV-PTLD. Mechanistically, we first found that LZTS2 acts as a tumor suppressor gene in EBV-PTLD, and BHRF1-1 and BART2-5p can simultaneously inhibit LZTS2 and activate PI3K-AKT pathway. This study shows that BHRF1-1 and BART2-5p can simultaneously inhibit the expression of tumor suppressor LZTS2, and activate the PI3K-AKT pathway, leading to the occurrence and development of EBV-PTLD.Therefore, BHRF1-1 and BART2-5p are expected to be potential diagnostic markers and therapeutic targets for EBV-PTLD patients.

αβ and γδ T-cell responses to Epstein-Barr Virus: insights in immunocompetence, immune failure and therapeutic augmentation in transplant patients.

Epstein-Barr Virus (EBV) is a human gamma herpes virus, which causes several diseases in immunocompetent (mononucleosis, chronic fatigue syndrome, gastric cancer, endemic Burkitt's lymphoma, head and neck cancer) and immunosuppressed (post-transplant lymphoproliferative disease, EBV-associated soft tissue tumors) patients. It elicits a complex humoral and cellular immune response with both innate and adaptive immune components. Substantial progress has been made in understanding the interplay of immune cells in EBV-associated diseases in recent years, and several therapeutic approaches have been developed to augment cellular immunity toward EBV for control of EBV-associated malignancy. This review will focus on recent developments in immunosuppressed transplant recipients.

Downregulation of MUS81 expression inhibits cell migration and maintains EBV latent infection through miR-BART9-5p in EBV-associated gastric cancer.

Epstein-Barr virus (EBV) infection is associated with the occurrence and development of gastric cancer (GC). Methyl methanesulfonate and ultraviolet-sensitive gene 81 (MUS81) is the catalytic component of a structure-specific endonuclease and plays an important role in chromosomal stability. However, the link between EBV infection and MUS81 remains unclear. In the present study, we found that MUS81 expression was much lower in EBV-associated GC cells than in EBV-negative GC. MUS81 acts as an oncogene in GC by inducing the cell migration and proliferation. Western blot and luciferase reporter assays revealed that miR-BART9-5p directly targeted MUS81 and downregulated its expression. Additionally, overexpression of MUS81 in EBV-positive GC cells inhibited the expression of EBV nuclear antigen 1 (EBNA1). EBNA1 is critical for the pathogenesis of EBV-associated tumors and the maintenance of a stable copy number of the viral genomes. Altogether, these results indicated that the lowering MUS81 expression might be a mechanism by EBV to maintain its latent infection.

Upregulation of Apolipoprotein L6 Improves Tumor Immunotherapy by Inducing Immunogenic Cell Death.

In the past few years, immune checkpoint blockade (ICB) therapy has emerged as a breakthrough treatment for cancers and has demonstrated inspiring effects in tumor patients with Epstein-Barr virus (EBV) infection. To allow more patients to benefit from immunotherapy, exploring novel biomarkers based on EBV-related tumors and immunotherapy cohorts was pursued in the present study. The essential biomarkers that may enhance antitumor immunity across EBV-related tumors were identified using the large-scale transcriptomic profiles of EBV-associated tumors and tumor immunotherapy cohorts. The clinical significance of vital genes was evaluated in multiple tumor immunotherapy cohorts. Moreover, the potential function of essential genes in immunotherapy was explored via bioinformatic analyses and verified by qRT-PCR, Western blot analysis, CCK8 assay and flow cytometry. Apolipoprotein L6 (APOL6) was considered the essential biomarker for enhancing antitumor immunity across EBV-positive tumors. The upregulation of APOL6 was correlated with increased response rates and prolonged survival in multiple tumor immunotherapy cohorts. Bioinformatic analyses suggested that APOL6 may enhance tumor immunotherapy by inducing immunogenic cell death. Pancreatic cancer cells transfected with APOL6 overexpression plasmid underwent apoptosis, necroptosis, and pyroptosis with immunogenic features. The biomarker upregulated in EBV-related tumors could further elucidate the drivers of immunotherapy response. The upregulation of APOL6 could improve immunotherapy by triggering immunogenic cell death, thus offering a new target to optimize cancer immunotherapy.

PD-L1 is upregulated in CD163+ tonsillar macrophages from children undergoing EBV primary infection.

Epstein-Barr Virus (EBV) is a tumor associated virus that modulates not only the infected cells but also innate and adaptive immunity. Macrophages play a key role in tumor development and progression. Particularly, the M2 phenotype (CD163) with anti-inflammatory activity contributes to a favorable microenvironment for tumor development while the M1 (CD68) proinflammatory phenotype contributes to a restrictive one. In the context of pediatric EBV infection, little is known about macrophage contribution to PD-L1 expression, a molecule involved in immune exhaustion. We studied tonsils of primary infected (PI), healthy carriers (HC), reactivated (R), and not infected (NI) pediatric patients. Positive correlations were demonstrated for CD68+PD-L1+ in R and for CD163+PD-L1+ only in PI. Furthermore, CD163+PD-L1+ cell numbers were higher than PD-L1+CD68+ in PI patients. In addition, a positive correlation between PD-L1+CD163+ cells and LMP1 viral latent protein was observed in PI patients, and a positive correlation between PD-L1+CD68+ cells and BMRF1 lytic antigen was demonstrated. A positive correlation between TGF-β and PD-L1 expression was demonstrated in HC patients. Our findings indicate that EBV's lytic and latent antigens might be regulating macrophages' PD-L1 expression, particularly in PI patients, whereas, surprisingly, only TGF-β could be related to total PD-L1 upregulation. Given the relevance of macrophages and the PD-1/PD-L1 pathway in tumor progression and survival, more studies in early EBV infection could help to develop EBV-associated tumor therapies.

The lytic phase of Epstein-Barr virus plays an important role in tumorigenesis.

Epstein-Barr virus (EBV) is a recognized oncogenic virus that is related to the occurrence of lymphoma, nasopharyngeal carcinoma (NPC), and approximately 10% of gastric cancer (GC). EBV is a herpesvirus, and like other herpesviruses, EBV has a biphasic infection mode made up of latent and lytic infections. It has been established that latent infection promotes tumorigenesis in previous research, but in recent years, there has been new evidence that suggests that the lytic infection mode could also promote tumorigenesis. In this review, we mainly discuss the contribution of the EBV lytic phase to tumorigenesis, and graphically illustrate their relationship in detail. In addition, we described the relationship between the lytic cycle of EBV and autophagy. Finally, we also preliminarily explored the influence of the tumorigenesis effect of the EBV lytic phase on the future treatment of EBV-associated tumors.

Epstein-Barr virus in Adygeans and Slavs in Russia: virus types, <i>LMP1</i> variants, and malignant tumors

Introduction. It is known that the structural features of the Epstein-Barr virus (EBV) affect the manifestation of its biological properties. Based on differences in the sequences of the EBNA2, EBNA3A, -B, and -C genes, two types of the virus, EBV-1 and EBV-2, have been identified that have different ability to transform B cells in vitro and possibly playing certain role in the development of EBV-associated neoplasms.Aim. To study the prevalence of EBV-1 and EBV-2 in two ethnic groups, Аdygeans and Slavs, as well as the contribution of EBV-associated tumors to the overall incidence of malignant neoplasms certain organs and tissues.Materials and methods. DNA samples were extracted from 59 oral lavages of ethnic Аdygeans from Republic of Adygea and 40 such from oral cavity of ethnic Slavs of Moscow city. These samples were used for amplification of EBV DNA, determination of the concentration of viral DNA copies per 1 cell washout, as well as for amplification of EBV LMP1 followed by sequencing of the resulting gene samples and determination of their protein variant (LMP1).Results. Studies have shown that among the representatives of the Аdygeans the 2nd EBV type prevails, and among the Slavs, the 1st one. Epstein-Barr virus isolates in representatives of the two ethnic groups also differed in the structure of LMP1. Among the Slavs, a set of its LMP1 variants (B95.8/A, China, Med- and NC) was identified. However, among the Adygeans, the only variant - B95.8 and its subtype - B95.8/A was identified. EBV-1, which prevails among the representatives of the Slavs and has the ability to transform B-cells, was projected onto a higher incidence of tumors of the pharynx, stomach, Hodgkin's and non-Hodgkin's lymphomas (where EBV-associated cases cam occur) in the population of Moscow than in the population of the Republic of Adygea. However, the differences between incidence rates for these neoplasms (with the exception for the stomach tumors) were not statistically significant (p >0.5). A higher and statistically significantly different incidence rate of stomach cancer in residents of Moscow city, compared with that in residents of the Republic of Adygea, in our opinion, is not due to EBV-1 type and/or LMP1 variants, but rather is associated with a genetic predisposition the population of Moscow city to this tumor.Conclusion. The fact that two ethnic groups of Russia were found to be prevails by different types of EBV raises the question of their ethno-geographical association and their role in the induction of EBV-associated tumors. To resolve this issue additional studies in other geographical regions of Russia among representatives of different ethnic groups are required.

Designing a vaccine-based therapy against Epstein-Barr virus-associated tumors using immunoinformatics approach

Epstein-Barr virus (EBV) is widely known due to its role in the etiology of infectious mononucleosis. However, it is the first oncovirus that was identified and has been implicated in the etiology of several types of cancers. Globally, EBV infection is associated with more than 200, 000 new cancer cases and 150, 000 deaths yearly. A prophylactic or therapeutic vaccine targeting tumors associated with EBV infection is currently lacking. Therefore, this study aimed to develop a multiepitope-based polyvalent vaccine against EBV-associated tumors using immunoinformatics approach. The latency-associated proteins (LAP) of three strains of the virus were used in this study. Potential epitopes predicted from the proteins were analyzed and selected based on several predicted properties. Thirty viable B-cell and T-cell epitopes were selected and conjugated using various linkers alongside beta-defensin 3 as an adjuvant and pan HLA DR-binding epitope (PADRE) sequence to improve the immunogenicity of the vaccine construct. Molecular docking studies of the vaccine construct against toll-like receptors (TLRs) showed it is capable of inducing immune response via recognition by TLRs while immune simulation studies showed it could induce both cellular and humoral immune responses. Furthermore, molecular dynamics study of the complex formed by the vaccine candidate and TLR-4 showed that the complex was stable. Ultimately, the designed vaccine showed desirable properties based on in silico evaluation; however, experimental studies are needed to validate the efficacy of the vaccine against EBV-associated tumors.