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

• 批准号: 9891040
• 负责人: Shannon Celeste Kenney
• 金额: $ 50.75万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 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/9891040
• 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

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.

项目摘要 /摘要 爱泼斯坦 - 巴尔病毒（EBV）是全球人类癌的重要原因，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是 公认的是，裂解病毒蛋白的重要性仍然相对有争议。然而，裂解 有效的EBV诱导的淋巴瘤可能需要在EBV感染细胞的子集中感染。 形成。我们先前表明了裂解缺陷的EBV突变体（缺少BZLF1（z） （即）基因）在人源化小鼠模型中形成淋巴瘤的能力受到损害 病毒传播。此外，我们和其他人确定了生长因素和免疫抑制因素 从抒情感染的B细胞中释放，可能会增强附近受感染的生长和存活 B细胞。此外，我们最近发现BZLF1启动子变体（称为ZP-V3） 在某些EBV阳性恶性肿瘤（包括NPC和与AIDS相关的淋巴瘤）相对的过分代表性 由于其在非机场组织中的频率赋予了增强的裂解病毒重新激活，因此由于结合了 细胞NFAT转录因子到ZP-V3变体（但不是原型启动子ZP-P）。虽然 启动子的ZP-V3形式在1型EBV菌株中相对罕见，它存在于所有2型菌株中 （在非洲的疟疾带中很常见）。这些结果表明增强的裂解EBV感染 增加了EBV诱导的淋巴瘤在体内的可能性，并且是特定的癌症相关变体 Z启动子促进了EBV感染的B细胞中的裂解感染。在此提案中，我们将使用两个不同的 人性化小鼠模型比较包含ZP-P形式的EBV的表型与癌症 BZLF1启动子的相关（ZP-V3）形式，并探索裂解EBV感染的机制 促进淋巴作用。我们还将确定疟疾感染的EBV负载是否更高 与含有EBV菌株的ZP-V3共同感染的儿童与包含ZP-P菌株的儿童。我们的具体目标是 1）使用人源化的小鼠模型检查ZP-V3的体内表型与包含ZP-P的类型 1或2型EBV菌株； 2）比较BALF5（病毒DNA聚合酶）的表型。 人源化小鼠中的bzlf1删除的EBV突变体，并探索是否会阻塞裂解EBV DNA复制 抗病毒药物Acyclovir抑制了EBV诱导的淋巴瘤的发展。 3）确定 ZP-V3启动子变体是否与疟疾感染的非洲血浆EBV较高有关 孩子们。我们假设EBV ZP-V3变体将增强EBV诱导的人源化淋巴瘤 小鼠通过增加裂解EBV感染，并且该变体也与增强的裂解EBV有关 疟疾感染儿童的复制。如果是这样，这些结果将表明ZP-V3变体的存在 可能是预测EBV引起的人类恶性肿瘤风险增加的有用生物标志物。