Role of EBV Lytic Infection in Viral Tumorigenesis

EBV 裂解性感染在病毒肿瘤发生中的作用

基本信息

批准号：
10428543
负责人：
Shannon Celeste Kenney
金额：
$ 49.83万
依托单位：
UNIVERSITY OF WISCONSIN-MADISON
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-07-01 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10428543
关键词：
AIDS-Related Lymphoma Acyclovir Africa African Antiviral Agents Automobile Driving B-Lymphocytes BZLF1 gene Binding Biological Markers Cells Child DNA biosynthesis DNA-Directed DNA Polymerase Development Early Promoters Epithelial Cells Epstein-Barr Virus Infections Epstein-Barr Virus latency FDA approved Frequencies Gene Expression Growth Growth Factor Horizontal Disease Transmission Human Human Herpesvirus 4 Immediate-Early Genes Immunocompetent Immunosuppression Impairment In Vitro Individual LMP1 Laboratories Lymphoma Lymphomagenesis Lytic Lytic Phase Malaria Malignant Neoplasms Modeling Mutation Nasopharynx Carcinoma Non-Malignant Nuclear Pore Complex Patients Pharmaceutical Preparations Phenotype Plasma Polymerase Gene Proteins Risk Role Tissues Umbilical Cord Blood Variant Viral Viral Genes Viral Load result Viral Proteins Viral load measurement Virus Diseases Virus Replication Xenograft Model co-infection humanized mouse in vivo infected B cell lytic gene expression lytic replication malaria infection mouse model mutant neoplastic cell predictive marker prevent promoter prototype release factor transcription factor tumor tumorigenesis vaccination strategy viral DNA viral transmission virus related cancer

项目摘要

PROJECT SUMMARY / ABSTRACT Epstein-Barr virus (EBV) is an important cause of human cancers world-wide, including both B cell and epithelial cell malignancies. Although the role of EBV-encoded latency proteins in driving these cancers is well accepted, the importance of lytic viral proteins remains relatively controversial. Nevertheless, lytic infection in a subset of EBV-infected cells in vivo may be required for efficient EBV-induced lymphoma formation. We previously showed that a lytic-defective EBV mutant (missing the BZLF1 (Z) immediate-early (IE) gene) is impaired for the ability to form lymphomas in a humanized mouse model that allows horizontal virus transmission. In addition, we and others have identified growth factors and immunosuppressive factors released from lytically infected B cells that likely enhance the growth and survival of nearby latently infected B cells. Furthermore, we have recently discovered that a BZLF1 promoter variant (known as Zp-V3) that is over-represented in certain EBV-positive malignancies (including NPC and AIDS-related lymphomas) relative to its frequency in non-malignant tissues confers enhanced lytic viral reactivation in vitro due to binding of the cellular NFAT transcription factor to the Zp-V3 variant (but not the prototype promoter, Zp-P). Although the Zp-V3 form of the promoter is relatively uncommon in type 1 EBV strains, it is present in all type 2 strains (which are very common in the malaria belt of Africa). These results suggest that enhanced lytic EBV infection increases the likelihood of EBV-induced lymphomas in vivo, and that a particular cancer-associated variant of the Z promoter promotes lytic infection in EBV-infected B cells. In this proposal, we will use two different humanized mouse models to compare the phenotypes of EBV containing the Zp-P form versus the cancer- associated (Zp-V3) form of the BZLF1 promoter, and to explore mechanism(s) by which lytic EBV infection promotes lymphomagenesis. We will also determine whether EBV loads are higher in malaria-infected children co-infected with Zp-V3 containing EBV strains versus Zp-P containing strains. Our Specific Aims are 1) to use humanized mouse models to examine the in vivo phenotypes of Zp-V3 versus Zp-P containing type 1 or type 2 EBV strains; 2) to compare the phenotypes of BALF5 (the viral DNA polymerase)-deleted versus BZLF1-deleted EBV mutants in humanized mice, and explore whether blocking lytic EBV DNA replication with the antiviral drug, acyclovir, inhibits the development of EBV-induced lymphomas; and 3) to determine whether the Zp-V3 promoter variant is associated with higher plasma levels of EBV in malaria-infected African children. We hypothesize that the EBV Zp-V3 variant will enhance EBV-induced lymphomas in humanized mice by increasing lytic EBV infection, and that this variant is also associated with enhanced lytic EBV replication in malaria-infected children. If so, these results will suggest that the presence of the Zp-V3 variant may be a useful biomarker for predicting increased risk of EBV-induced malignancy in humans.

项目概要/摘要 Epstein-Barr 病毒 (EBV) 是全世界人类癌症的重要原因，包括 B 细胞和上皮细胞恶性肿瘤。尽管 EBV 编码的潜伏蛋白在驱动这些癌症中的作用尚不清楚尽管已被广泛接受，但裂解病毒蛋白的重要性仍然存在相对争议。尽管如此，溶解有效的 EBV 诱导淋巴瘤可能需要体内感染 EBV 感染细胞的子集形成。我们之前表明，裂解缺陷型 EBV 突变体（缺失 BZLF1 (Z) 立即早期（IE）基因）在人源化小鼠模型中形成淋巴瘤的能力受损，该模型允许水平病毒传播。此外，我们和其他人还发现了生长因子和免疫抑制因子从裂解性感染的 B 细胞中释放出来，可能会增强附近潜伏感染的 B 细胞的生长和存活 B细胞。此外，我们最近发现了 BZLF1 启动子变体（称为 Zp-V3）在某些 EBV 阳性恶性肿瘤（包括鼻咽癌和艾滋病相关淋巴瘤）中比例过高由于其在非恶性组织中的出现频率，由于与 Zp-V3 变体的细胞 NFAT 转录因子（但不是原型启动子 Zp-P）。虽然 Zp-V3 形式的启动子在 1 型 EBV 毒株中相对不常见，它存在于所有 2 型毒株中（这在非洲疟疾带非常常见）。这些结果表明增强的裂解性 EBV 感染增加了 EBV 体内诱发淋巴瘤的可能性，并且特定的癌症相关变异 Z 启动子的启动子促进 EBV 感染的 B 细胞的裂解感染。在本提案中，我们将使用两种不同的人源化小鼠模型来比较包含 Zp-P 形式的 EBV 与癌症的表型 BZLF1启动子的相关（Zp-V3）形式，并探索裂解性EBV感染的机制促进淋巴瘤发生。我们还将确定感染疟疾的人中 EBV 载量是否较高儿童同时感染含有 Zp-V3 的 EBV 菌株与含有 Zp-P 的菌株。我们的具体目标是 1) 使用人源化小鼠模型来检查 Zp-V3 与 Zp-P 含有型的体内表型 1型或2型EBV毒株； 2) 比较 BALF5（病毒 DNA 聚合酶）删除与删除的表型人源化小鼠中 BZLF1 缺失的 EBV 突变体，并探讨是否用抗病毒药物阿昔洛韦可抑制 EB 病毒诱导的淋巴瘤的发展； 3) 确定 Zp-V3 启动子变异是否与感染疟疾的非洲人血浆中较高的 EBV 水平相关孩子们。我们假设 EBV Zp-V3 变体将增强人源化中 EBV 诱导的淋巴瘤小鼠通过增加裂解性 EBV 感染，并且该变体也与增强的裂解性 EBV 相关在感染疟疾的儿童中复制。如果是这样，这些结果将表明 Zp-V3 变体的存在可能是预测人类 EB 病毒诱发恶性肿瘤风险增加的有用生物标志物。