New EBV Therapies for treating malignancies

描述(申请人提供)：爱泼斯坦-巴尔病毒(EBV)引起或与多种疾病有关，从传染性单核细胞增多症到免疫受损患者的危及生命的淋巴增生性疾病。EBV在特定肿瘤类型中的持续存在，如艾滋病相关的中枢神经系统和其他B细胞淋巴瘤，为开发高度特异的病毒靶向治疗方法提供了潜力。这项建议将一种新的潜在靶标--EBV BGLF4编码的蛋白激酶(EBV PK)的基础研究与应用研究结合起来，其中该激酶将被测试为治疗EBV阳性和EBV阴性肿瘤的“自杀”基因(结合更昔洛韦治疗)或作为治疗EBV驱动的淋巴瘤的“治疗性”基因。在目标1中，我们通过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靶点开始，从EBV BMRF1基因编码的病毒DMA聚合酶处理因子等已知靶点开始，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。在目标2中，我们研究了EBV EBNA2蛋白的磷酸化，EBV EBNA2蛋白是EBV淋巴增殖性疾病特有的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的治疗方法来治疗EBV驱动的淋巴增殖，即通过解除对3型EBV潜伏期的管制。在目标3中，我们开发了使用EBV激酶，包括PK和TK，来治疗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，研究了激酶将更昔洛韦转化为细胞毒形式的有效性，以及引发病毒重新激活的化疗药物和更昔洛韦的组合抑制含有野生型EBV的淋巴瘤或缺乏这两种激酶的突变株的生长的能力。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，导致治疗重要的EBV相关恶性肿瘤的新方法。

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.