LSUHSC COBRE:POLYAMINE METABOLISM IN EBV LYMPHOMAGENESIS

LSUHSC COBRE：EBV 淋巴细胞生成中的多胺代谢

• 批准号: 7610514
• 负责人: RONA S SCOTT
• 金额: $ 26.11万
• 依托单位: LOUISIANA STATE UNIV HSC SHREVEPORT
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7610514
• 关键词: Bioinformatics; Burkitt Lymphoma; Cell Line; Cells; Chromatin; Clone Cells; Computer Retrieval of Information on Scientific Projects Database; DNA; DNA Methyltransferase; DNA Modification Methylases; E-Cadherin; Enzymes; Epigenetic Process; Epstein-Barr Virus Infections; Foundations; Funding; Gene Expression; Gene Silencing; Genes; Genome; Grant; Human; Human Herpesvirus 4; In Vitro; Individual; Infection; Institution; Lymphomagenesis; Maintenance; Malignant - descriptor; Malignant Epithelial Cell; Malignant Neoplasms; Mediating; Membrane Proteins; Messenger RNA; Metabolic Pathway; Metabolism; Methylation; Methyltransferase; MicroRNAs; Modification; Numbers; Oncogenic Viruses; Phenotype; Polyamine Catabolism; Polyamines; Progress Reports; Proteins; Reporting; Research; Research Personnel; Resources; Running; Source; Spermidine/Spermine N1-Acetyltransferase; Testing; Transfection; United States National Institutes of Health; Viral; Virus; cell growth; cellular targeting; imprint; inhibitor/antagonist; malignant phenotype; promoter; tumor

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Project 2-A: Analysis of Polyamine Metabolism in EBV Lymphomagenesis In the Burkitts lymphoma (BL) cell line Akata, maintenance of the malignant phenotype in vitro is dependent on retention of the EBV genome. Global gene expression analysis of paired EBV-positive and -negative Akata cell clones identified spermidine/spermine N1-acetyltransferase (SSAT) as one of a limited number of genes whose expression was significantly decreased in EBV-positive clones. SSAT is a key enzyme in the catabolism of polyamines, which are essential for cell growth. Increased polyamine levels have been detected in a number of tumors. Thus, we sought to test the hypothesis that decreased SSAT mRNA in EBV-infected cells represents viral manipulation of the polyamine metabolic pathway and a factor in EBV lymphomagenesis. We have concluded the polyamine studies, with final progress reported below. Those studies have provided the foundation for a new direction, outlined in project 2-B. Project 2-B: EBV microRNA-Mediated Epigenetic Modification of Cellular Chromatin Carcinoma cell lines infected by EBV in vitro developed subclones that lost virus but stably retained a morphological phenotypic, induced at infection, which distinguished them from the EBV-negative parental cell line. When transiently infected clones were compared by gene expression arrays to their EBV-negative parental counterparts, some 80 downregulated genes (many of which are hypermethylated in cancer) were identified in cells that had lost virus. Treatment with methyltransferase inhibitors restored the parental cell morphologic phenotype (and, in cases tested, gene expression). These preliminary observations have led us to test the hypothesis that EBV induces stable epigenetic changes that may make virus redundant with respect to continued malignant progression. Retention of a virally-induced epigenetic imprint in transiently infected cells introduces a new paradigm for how a human tumor virus might mechanistically regulate a cell in a hit-and-run fashion. We will focus on determining which EBV gene products contribute to epigenetic modification of cellular chromatin. EBV latent membrane protein 1 (LMP1) has been reported to induce DNA methyltransferase 1, 3a, and 3b and hypermethylate the E-cadherin promoter. However, the discovery of at least 17 EBV microRNAs (miRNAs), together with the ability of cellular miRNAs to target DNA for gene silencing, prompted our hypothesis that the EBV miRNAs direct methylation of specific cellular genes in a sequence specific manner. Using bioinformatic approaches, we will query which EBV miRNAs might target these cellular promoters. Transfection of the individual miRNA will provide a direct demonstration that candidate miRNAs so identified do in fact produce epigenetic silencing in EBV infection.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 项目2-A：EBV淋巴作用中多胺代谢的分析 在Burkitt S淋巴瘤（BL）细胞系AKATA中，体外的恶性表型的维持取决于EBV基因组的保留。配对的EBV阳性和阴性AKATA细胞克隆的全球基因表达分析鉴定出精子/精子N1-乙酰基转移酶（SSAT）是有限数量的基因之一，其表达在EBV阳性克隆中显着降低。 SSAT是多胺的分解代谢中的关键酶，这对于细胞生长至关重要。在许多肿瘤中已经检测到多胺水平升高。 因此，我们试图检验以下假设：EBV感染细胞中SSAT mRNA的降低代表了多胺代谢途径的病毒操纵和EBV淋巴细胞化的因素。 我们已经得出了多胺研究的结论，下面报告了最终的进展。 这些研究为2-B项目中概述的新方向提供了基础。 项目2-B：EBV microRNA介导的细胞染色质的表观遗传修饰 受EBV感染的癌细胞系在体外开发了丢失病毒但稳定保留的形态表型，在感染时诱导的形态表型，这将它们与EBV阴性亲本细胞系区分开。 当通过基因表达阵列瞬时感染的克隆与其EBV阴性亲本对应物进行比较时，在丧失病毒的细胞中鉴定了大约80个下调的基因（其中许多是癌症中的高甲基化）。 用甲基转移酶抑制剂治疗可恢复亲本细胞的形态表型（在经过测试的基因表达的情况下）。 这些初步观察结果使我们检验了以下假设：EBV诱导稳定的表观遗传变化，这可能会使病毒相对于持续的恶性进展。 瞬时感染细胞中病毒诱导的表观遗传印记的保留引入了一种新的范式，以了解人类肿瘤病毒如何以撞击方式机械地调节细胞。 我们将专注于确定哪种EBV基因产物有助于细胞染色质的表观遗传修饰。 据报道，EBV潜在膜蛋白1（LMP1）诱导DNA甲基转移酶1、3A和3B，并诱导E-钙粘蛋白启动子甲基化。 然而，发现至少17个EBV microRNA（miRNA），以及细胞miRNA靶向基因沉默的能力，促使我们的假设是EBV miRNA以序列特定方式将特定细胞基因的甲基化直接甲基化。 使用生物信息学方法，我们将询问EBV miRNA可能针对这些细胞启动子的方法。 单个miRNA的转染将提供直接的证明，即被鉴定出的候选miRNA实际上会在EBV感染中产生表观遗传沉默。