New EBV Therapies for treating malignancies

描述（由申请人提供）：爱泼斯坦-巴尔病毒（EB病毒）引起或与多种严重程度不同的疾病相关，从传染性单核细胞增多症到免疫功能低下患者危及生命的淋巴组织增生性疾病。EBV在特定肿瘤类型中的持续存在，如AIDS相关的CNS和其他B细胞淋巴瘤，为开发高度特异性的病毒靶向治疗提供了可能。该提议将新的潜在靶点EBV BGLF 4编码的蛋白激酶（EBV PK）的基础研究与应用研究相结合，其中将激酶作为用于治疗EBV阳性和EBV阴性肿瘤的“自杀”基因（与更昔洛韦治疗结合）或作为用于治疗EBV驱动的淋巴瘤的“治疗性”基因进行测试。在目的1中，我们通过使用RNAi敲除其表达来研究EBV PK在病毒感染中的作用。然后，我们在RNA和蛋白质水平上分析了病毒裂解感染的过程，从已知的EBV PK靶点开始，例如由EBV BMRF 1基因编码的病毒DNA聚合酶持续合成因子，并将研究扩展到新发现的靶点。在目的2中，我们研究了EBV EBNA 2蛋白的磷酸化，EBNA 2蛋白是EBV淋巴增生性疾病特征性EBV 3型潜伏期程序的主要调节因子，也是新发现的EBV PK靶点。基于这一发现，我们还提出了一种新的潜在的治疗方法来治疗EBV驱动的淋巴细胞增生，即通过放松3型EBV潜伏期。在目标3中，我们开发了使用EBV激酶（PK和胸苷激酶（TK））治疗EBV阳性和EBV阴性恶性肿瘤的方法。我们研究，首先在细胞培养，然后在人类疾病的动物模型中，在转换更昔洛韦其细胞毒性形式的激酶的功效，和化疗药物的组合，触发病毒再激活和更昔洛韦抑制淋巴瘤的生长的能力，含有野生型EBV或突变体缺乏激酶。因此，这项研究将揭示EBV PK在病毒感染中的作用，并最终导致治疗重要EBV相关恶性肿瘤的新方法，基于植根于EBV病毒学基础的新概念。

DESCRIPTION (provided by applicant): Epstein-Barr virus (EBV) causes or is associated with a wide range of diseases varying in severity from infectious mononucleosis to life-threatening lymphoproliferative diseases in immunocompromised patients. The consistent presence of EBV in particular tumor types, such as AIDS-associated CNS and other B-cell lymphomas, offers the potential for the development of highly specific, virus-targeted therapies. This proposal combines basic studies of a novel potential target, EBV BGLF4-encoded protein kinase (EBV PK), with applied studies, wherein the kinase will be tested as a "suicide" gene for treatment of EBV-positive and EBV negative tumors (in conjunction with ganciclovir treatment) or as a "therapeutic" gene for treatment of EBV driven lymphomas. In Aim 1, we study the role of EBV PK in viral infection by knocking out its expression using RNAi. We then analyze the course of viral lytic infection at the RNA and protein levels, starting with known EBV PK targets, such as viral DMA polymerase processivity factor, encoded by the EBV BMRF1 gene, and extending the research to newly discovered targets. In Aim 2, we investigate the phosphorylation of EBV EBNA2 protein, the master regulator of the EBV type 3 latency program characteristic of EBV lymphoproliferative diseases, and a newly discovered EBV PK target. Based on this finding, we also propose a novel potential therapeutic approach for treating EBV-driven lymphoproliferations, that is, by deregulation of type 3 EBV latency. In Aim 3, we develop ways to use EBV kinases, both PK and thymidine kinase (TK), to treat EBV-positive and EBV-negative malignancies. We study, first in cell culture and then in animal models of human disease, the efficacy of the kinases in converting ganciclovir to its cytotoxic form, and the ability of combinations of chemotherapeutic agents that trigger viral reactivation and ganciclovir to inhibit the growth of lymphomas containing wild type EBV or mutants lacking either kinase. Hence this research will reveal the role of EBV PK in viral infection and ultimately lead to new approaches for treatment of important EBV-related malignancies, based on new concepts rooted in fundamentals of the virology of EBV.