Epstein-Barr virus LMP1 mediated oncogenicity

摘要 γ-疱疹病毒驱动的淋巴增生性疾病导致HIV+患者的显著死亡率 人口。尽管有高度有效的抗逆转录病毒治疗，艾滋病毒阳性个体仍然处于高风险之中 EB病毒（EBV）相关的B细胞癌。EBV在>40%的 免疫母细胞性弥漫性大B细胞淋巴瘤和近100%的霍奇金淋巴瘤， HIV阳性个体的原发性中枢神经系统淋巴瘤。EBV转化人类B细胞 淋巴母细胞样细胞系（LCL），EBV驱动的免疫母细胞淋巴瘤的主要模型， 免疫抑制宿主。然而，关键的EBV诱导的宿主依赖性因素仍然是 阐明。因此，我们使用系统的方法来深入了解关键的EBV癌蛋白 目标的我们使用：1）全基因组CRISPR筛选来识别宿主依赖性因素 EBV癌蛋白下游; 2）多重质谱法以创建蛋白质组图谱 EBV介导的B细胞转化;和3）ChIP-seq以鉴定EBV癌蛋白宿主 基因组靶点，发现了第一个病毒超级增强子（SE），由5个LMP 1- 活化的NF-κ B和4种EBV核抗原亚单位。这些都集中在转录 因子BATF、IRF 4和IRF 2作为关键的LMP 1靶向宿主依赖性因子。我们的初步 研究表明，BATF/IRF 4和IRF 2复合物在EBV中具有关键的依赖因子作用 癌蛋白驱动的MYC表达，是LCL生长和存活所必需的。我们建议 定义病毒癌蛋白超增强剂BATF/IRF 4和IRF 2之间的相互作用 复合物驱动淋巴母细胞样B细胞中的MYC表达。我们的具体目标是（1） 确定EBV癌蛋白如何激活依赖因子BATF/IRF 4复合物以诱导 （2）确定BATF/IRF 4在EBV癌蛋白诱导的MYC诱导中的关键作用， 淋巴母细胞样B细胞;和（3）确定病毒SE驱动的依赖因子IRF 2是如何被 这是支持淋巴母细胞MYC表达所必需的。这些研究专门针对 PA-16-426通过提高对发展，进展和治疗的理解， 在具有潜在HIV感染的个体中观察到的恶性肿瘤。拟议的研究是 预计将有助于理解EBV癌蛋白和关键的遗传定义 下游宿主依赖因子重编程淋巴母细胞样细胞MYC表达。EBV 癌蛋白可能不是药物，但SE和IRF 4是越来越多的治疗靶点。以来 病毒癌蛋白诱导的MYC表达对于EBV转化的B细胞生长至关重要， 这些研究的长期目标是支持抑制病毒癌基因的合理方法 颠覆MYC。

Abstract Gamma-herpesvirus-driven lymphoproliferative disorders cause significant mortality in HIV+ populations. Despite highly active antiretroviral therapy, HIV+ individuals remain at elevated risk for Epstein-Barr virus (EBV)-associated B-cell cancers. EBV is identified in >40% of immunoblastic diffuse large B-cell lymphomas and nearly 100% of Hodgkin lymphoma and primary central nervous system lymphomas in HIV+ individuals. EBV transforms human B-cells into lymphoblastoid cell lines (LCL), a major model of EBV-driven immunoblastic lymphomas of immunosuppressed hosts. Yet, key EBV-induced host dependency factors remain to be elucidated. We therefore used systematic approaches to gain insights into key EBV oncoprotein targets. We used: 1) Genome-wide CRISPR screens to identify host dependency factors downstream of EBV oncoproteins; 2) Multiplexed mass spectrometry to create a proteomic map of EBV-mediated B-cell transformation; and 3) ChIP-seq to identify EBV oncoprotein host genomic targets, which found the first viral super-enhancers (SE), comprised of 5 LMP1- activated NF-kB and 4 EBV nuclear antigen subunits. These converged on the transcription factors BATF, IRF4 and IRF2 as key LMP1-targeted host dependency factors. Our preliminary studies indicate that BATF/IRF4 and IRF2 complexes have key dependency factor roles in EBV oncoprotein-driven MYC expression, necessary for LCL growth and survival. We propose to define how the interplay between viral oncoprotein superenhancers, BATF/IRF4 and IRF2 complexes drive MYC expression in lymphoblastoid B-cells. Our Specific Aims are to (1) Identify how EBV oncoproteins activate dependency factor BATF/IRF4 complexes to induce MYC; (2) Identify key BATF/IRF4 roles in EBV oncoprotein-induced MYC induction in lymphoblastoid B-cells; and (3) Identify how the viral SE-driven dependency factor IRF2 is necessary to support lymphoblastoid cell MYC expression. These studies specifically address PA-16-426 by advancing understanding of development, progression and treatment of malignancies observed in individuals with underlying HIV infection. The proposed studies are expected to contribute to understanding of how EBV oncoproteins and key genetically-defined downstream host dependency factors reprogram lymphoblastoid cell MYC expression. EBV oncoproteins may not be druggable, but SE and IRF4 are increasingly therapeutic targets. Since viral oncoprotein-induced MYC expression is critical for EBV-transformed B-cell growth, the longterm goal of these studies is to support rational approaches to restrain viral oncogene subversion of MYC.