Oncogenesis In Retrovirus-Induced Lung Cancer

逆转录病毒诱导的肺癌的肿瘤发生

• 批准号: 6467634
• 负责人: MASSIMO PALMARINI
• 金额: $ 25.71万
• 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/6467634
• 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）：该提案的目的是研究 卵巢肺癌（OPC）中肿瘤发生的机制，一种天然 发生绵羊的肺癌。 OPC是由称为逆转录病毒引起的 Jaagsiekte绵羊逆转录病毒（JSRV）。 OPC与人类有着惊人的相似之处 支气管肺泡癌（BAC），一种仅相关的肺肿瘤 吸烟，现在代表了所有肺癌的四分之一 美国逆转录病毒诱发的新肿瘤的动物模型已深入了解 癌症的遗传基础，并导致了癌基因的发现。因此，OPC 是研究肺癌发生的独特模型，也是唯一的病毒诱导的 家畜中的肺肿瘤。 JSRV和 通过隔离感染性和致病性，OPC已证明了OPC 分子克隆（JSRV2 1），但JSRV使用的机制诱导细胞 转型尚不清楚，是该提案的对象。这 JSRV包膜的表达足以诱导 经典转化测定中的啮齿动物成纤维细胞。这些结果表明 逆转录病毒引起的肿瘤发生的新机制。初步结果显示 磷酸肌醇-3引发的抗凋亡细胞信号传导途径 激酶（PL-3K）在JSRV转换的NIH3T3中具有组成性活性，但不在 父母细胞系。此外，复制能干的JSRV突变体 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一个单点突变 JSRV包膜的跨膜区域的细胞质尾巴改变了 PI-3K的推定对接站点。这些结果创造了令人兴奋的理由 对于这个提议，其目的是剖析和理解 JSRV在其自然宿主的体外和体内都诱导了癌变。目标1 是为了剖析JSRV包膜引发的信号转导途径 在啮齿动物成纤维细胞和从天然发生的OPC获得的细胞系中 瘤。但是，体内癌变的机制可能会更多 复杂的是，伴随JSRV转化永生的细胞系。在 AIM 2，新生羔羊将被基于JSRV的载体和突变体接种 将确定病毒包膜的表达和激活是否 PI-3K信号级联是必需的，并且/或足以诱导肺 致癌作用。目标3是寻找进一步的机制 通过分析自然中的病毒插入位点，OPC的肿瘤发生 发生的OPC案例。这些实验的完成将阐明 JSRV诱导的肺癌发生的分子机制，可能提供 阐明某些形式的人类发病机理的智力框架 肺癌。