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（由申请人提供）：本提案的目的是研究 绵羊肺癌 (OPC) 的肿瘤发生机制 羊发生肺癌。 OPC 是由一种称为 Jaagsiekte 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)，一种与此相关性较弱的肺部肿瘤 与吸烟有关，现在占全世界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已经深入了解了 癌症的遗传基础并导致癌基因的发现。因此，OPC 是研究肺癌发生的独特模型，也是唯一由病毒诱导的模型 家畜肺部肿瘤。 JSRV 与 JSRV 之间的因果关系 OPC 已通过感染性和致病性的分离得到证明 分子克隆（JSRV2 1），但 JSRV 诱导细胞的机制 转变是未知的，并且是本提案的目标。这 JSRV 包膜的表达足以诱导转化 经典转化测定中的啮齿动物成纤维细胞。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 磷酸肌醇3启动的抗凋亡细胞信号通路 激酶 (Pl-3K) 在 JSRV 转化的 NIH3T3 中具有组成型活性，但在 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。这些突变体在酪氨酸中具有单个单点突变 JSRV 包膜跨膜区的细胞质尾部发生改变 PI-3K 的假定对接站点。这些结果创造了一个令人兴奋的理由 这项提案的目的是剖析和理解 JSRV 在其自然宿主体内和体外诱导致癌作用。目标1 就是剖析JSRV包膜启动的信号转导通路 啮齿动物成纤维细胞和从天然 OPC 获得的细胞系中 瘤。然而，体内致癌机制可能更多 JSRV 转化永生化细胞系的复合体。在 目标 2，新生羔羊将接种基于 JSRV 的载体和突变体， 将决定病毒包膜的表达和激活是否 PI-3K 信号级联反应是必要和/或足以诱导肺 致癌作用。目标 3 是寻找进一步的机制来促进 通过分析自然中的病毒插入位点来了解 OPC 的肿瘤发生 发生 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，并可能提供 揭示某些人类疾病发病机制的知识框架 肺癌。