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）是一种自然发生的肺癌， 羊的肺癌。OPC是由逆转录病毒引起的， 绵羊肺结核逆转录病毒（JSRV）。OPC与人类有着惊人的相似性， 细支气管肺泡癌（BAC），一种与肺癌相关性很弱的肺肿瘤， 现在占世界所有肺癌的四分之一， 美国逆转录病毒诱导肿瘤的动物模型已经深入了解了 癌症的遗传基础，并导致了致癌基因的发现。因此，OPC 是研究肺癌发生的独特模型， 家畜的肺肿瘤。JSRV与 OPC已被证明是由分离的传染性和致病性 分子克隆（JSRV 2 - 1），但JSRV诱导细胞凋亡的机制 这些变化是未知的，也是本提案的目的。的 JSRV包膜的表达足以诱导转化， 啮齿动物成纤维细胞在经典的转化试验。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 磷酸肌醇-3启动的抗凋亡细胞信号通路 激酶（P1 - 3 K）在JSRV转化的NIH 3 T3中具有组成性活性，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， 得到了这些突变体在酪氨酸中有一个单一的点突变， JSRV包膜的跨膜区的胞质尾区改变了 PI-3 K的一个假定的对接位点。这些结果创造了一个令人兴奋的理由 这一建议的目的是剖析和理解的机制， JSRV在其天然宿主中的体外和体内诱导致癌作用。要求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天然存在的OPC获得的细胞系中， 肿瘤然而，体内致癌机制可能更多 这些复合物随后被JSRV转化永生化细胞系。在 目的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 PI-3 K信号级联是必要的和/或足以诱导肺 致癌作用目标3是寻找进一步的机制， 通过分析自然界中的病毒插入位点， 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， 一个知识框架，以解开某些形式的人类疾病的发病机制， 肺癌