New EBV Therapies for treating malignancies

描述（由申请人提供）：eb病毒（EBV）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中危及生命的淋巴细胞增生性疾病。EBV在特定肿瘤类型（如艾滋病相关中枢神经系统和其他b细胞淋巴瘤）中的持续存在，为开发高度特异性的病毒靶向治疗提供了潜力。该提案结合了一种新的潜在靶点EBV bglf4编码蛋白激酶（EBV PK）的基础研究和应用研究，其中该激酶将作为治疗EBV阳性和EBV阴性肿瘤的“自杀”基因（与更昔洛韦治疗结合）或作为治疗EBV驱动淋巴瘤的“治疗”基因进行测试。在Aim 1中，我们使用RNAi敲除EBV PK的表达，研究其在病毒感染中的作用。然后，我们从已知的EBV PK靶点（如EBV BMRF1基因编码的病毒DMA聚合酶加工因子）开始，从RNA和蛋白质水平分析病毒裂解感染的过程，并将研究扩展到新发现的靶点。在Aim 2中，我们研究EBV EBNA2蛋白的磷酸化，EBV EBNA2蛋白是EBV淋巴增生性疾病特征的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治疗方法来治疗EBV驱动的淋巴细胞增生，即通过解除3型EBV潜伏期。在Aim 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。我们首先在细胞培养中，然后在人类疾病的动物模型中，研究了将更昔洛韦转化为细胞毒性形式的激酶的功效，以及触发病毒再激活的化疗药物和更昔洛韦联合抑制含有野生型EBV或缺乏任何激酶的突变体的淋巴瘤生长的能力。因此，这项研究将揭示EBV PK在病毒感染中的作用，并最终基于植根于EBV病毒学基础的新概念，为治疗重要的EBV相关恶性肿瘤提供新方法。

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.