Oncogenesis In Retrovirus-Induced Lung Cancer

逆转录病毒诱导的肺癌的肿瘤发生

• 批准号: 6754416
• 负责人: MASSIMO PALMARINI
• 金额: $ 33.18万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-15 至 2006-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6754416
• 关键词: 3T3 cells; Retroviridae; artificial chromosomes; biological models; biological signal transduction; cell line; fibroblasts; fluorescent in situ hybridization; gene expression; genetic library; genetic screening; lung neoplasms; neoplasm /cancer genetics; neoplastic transformation; newborn animals; phosphatidylinositol 3 kinase; phosphorylation; point mutation; polymerase chain reaction; protein kinase; sheep; site directed mutagenesis; transfection /expression vector; viral carcinogenesis; virus envelope; virus related neoplasm /cancer

DESCRIPTION (provided by applicant): The object of this proposal is to study the mechanisms of oncogenesis in ovine pulmonary carcinoma (OPC), a naturally occurring lung cancer of sheep. OPC is caused by a retrovirus known as Jaagsiekte sheep retrovirus (JSRV). OPC has strikingly similarities with human bronchioalveolar carcinoma (BAC), a lung tumor that is only weakly associated with cigarette smoking and now represents a quarter of all lung cancers in the U.S. Animal models of retrovirus-induced neoplams have given insight into the genetic basis of cancer and have led to the discovery of oncogenes. Thus, OPC is a unique model to investigate lung carcinogenesis and the only viral-induced pulmonary neoplasm in domestic animals. The causal association between JSRV and OPC has been demonstrated by the isolation of an infectious and pathogenic molecular clone (JSRV2 1) but the mechanisms used by JSRV to induce cell transformation are not known and are the object of this proposal. The expression of the JSRV envelope is sufficient to induce transformation of rodent fibroblasts in classical transformation assays. These results suggest a novel mechanism in retroviral-induced oncogenesis. Preliminary results show that the antiapoptotic cell signaling pathway initiated by phosphoinositide-3 kinase (Pl-3K) is constitutively active in JSRV-transformed NIH3T3 but not in the parental cell line. In addition, replication competent JSRV mutants that have lost the ability to transform rodent fibroblasts in vitro have been obtained. These mutants have a single a single point mutation in a tyrosine of the cytoplasmic tail of the transmembrane region of the JSRV envelope altering a putative docking site for PI-3K. These results create an exciting rationale for this proposal whose aim is to dissect and understand the mechanisms of JSRV-induced carcinogenesis both in vitro and in vivo in its natural host. Aim 1 is to dissect the signal transduction pathway initiated by the JSRV envelope in rodent fibroblasts and in cell lines obtained from naturally occurring OPC tumor. However, the mechanisms of carcinogenesis in vivo are likely to be more complex that those followed by JSRV to transform immortalized cell lines. In Aim 2, newborn lambs will be inoculated with JSRV-based vectors and mutants that will determine whether the expression of the viral envelope and the activation of the PI-3K signaling cascade are necessary and/or sufficient to induce lung carcinogenesis. Aim 3 is to look for further mechanisms contributing to oncogenesis in OPC by analyzing the viral insertion sites in naturally occurring OPC-cases. The completion of these experiments will clarify the molecular mechanisms of JSRV-induced pulmonary carcinogenesis and might furnish an intellectual framework to unravel the pathogenesis of some forms of human lung cancer.

描述(申请人提供)：本提案的目的是研究 绵羊肺癌(OPC)的致癌机制 发生绵羊肺癌。OPC是由一种被称为 Jaagsiekte绵羊逆转录病毒(JSRV)OPC与人类有着惊人的相似之处 细支气管肺泡癌(BAC)是一种相关性很弱的肺癌 吸烟，现在占世界上所有肺癌的四分之一 美国逆转录病毒诱导的肿瘤动物模型提供了对 癌症的遗传学基础，并导致了癌基因的发现。因此，OPC 是一种研究肺癌发生的独特模型，也是唯一由病毒诱导的 家畜中的肺部肿瘤。JSRV和JSRV之间的因果关系 OPC已经通过分离出一种传染性和致病性的 分子克隆(JSRV21)，但JSRV诱导细胞的机制 转型是未知的，也是本提案的目标。这个 JSRV包膜的表达足以诱导转化 啮齿动物成纤维细胞的经典转化实验。这些结果表明， 逆转录病毒诱导肿瘤发生的新机制。初步结果显示 磷脂酰肌醇-3启动的抗细胞凋亡信号通路 在JSRV转化的NIH3T3中，Pl-3K具有结构性活性，而在NIH3T3中不具有结构性活性 亲代细胞系。此外，具有复制能力的JSRV突变体 已经失去了在体外转化啮齿动物成纤维细胞的能力 获得。这些突变体的酪氨酸有一个单一的单点突变 JSRV囊膜跨膜区的细胞质尾部改变 一个可能的PI-3K对接地点。这些结果创造了一个令人兴奋的理论基础 这一提案的目的是剖析和理解 JSRV在体内和体外对其自然宿主的致癌作用。目标1 是剖析JSRV包膜启动的信号转导途径 在啮齿动物成纤维细胞和从自然发生的OPC获得的细胞系中 肿瘤。然而，体内致癌的机制可能更多 这些复杂的JSRV紧随其后，转化永生化细胞系。在……里面 目的2，将基于JSRV的载体和突变体接种新生羔羊， 将决定病毒包膜的表达和激活 PI-3K信号级联是诱发肺的必要条件和/或充分条件 致癌。目标3是寻找有助于 分析OPC中天然病毒插入部位的致癌作用 正在发生的OPC病例。这些实验的完成将澄清 JSRV诱导肺癌发生的分子机制及可能提供的信息 一个解开某些形式人类致病机制的智力框架 肺癌。