ONCOGENESIS IN ANIMAL MODELS OF HUMAN CANCERS

人类癌症动物模型中的癌发生

• 批准号: 6289102
• 负责人: Lucy M Anderson
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6289102
• 关键词: autosomal dominant trait; cell cycle proteins; cell growth regulation; chemical carcinogen; chemical carcinogenesis; cyclin dependent kinase; cyclins; gastrointestinal neoplasms; gene deletion mutation; gene expression; gene mutation; immunocytochemistry; kidney neoplasms; laboratory rat; liver neoplasms; mycotoxins; neoplasm /cancer genetics; neoplastic process; nitrosamines; oncogenes; polymerase chain reaction; preneoplastic state; tumor suppressor genes; western blottings

Mutations in oncogenes and tumor suppressor genes in animal and human tumors may give important clues as to the exposures that led to the tumors. For rodent neoplasms that are pathologically similar to the corresponding human cancer, the rodent disease may be used to model the cellular events involved and to study prevention and therapy. Currently, we are focusing on the von Hippel-Lindau (VHL) gene in kidney cancer, and the K-ras gene in lung cancer.The VHL tumor suppressor gene is mutated in a high percentage of both familial and sporadic renal cell carcinomas. We have recently established an animal model for causation of VHL mutations in clear cell renal tumors, by the environmental carcinogen N-nitrosodimethylamine. In a parallel study, VHL protein has been expressed in normal rat kidney cells in culture. A remarkable and unanticipated finding, confirmed by both fluorescence microscopy and immunogold electron microscopy, is that the pVHL localizes to the mitochondria. In view of the many roles played by mitochondria in cytokine regulation, angiogenesis, and apoptosis, as well as energy metabolism, this finding may represent the rosetta stone to the functioning of pVHL. In studies of the role of the oncogene K- ras in genesis of adenocarcinoma of the lung, we are utilizing a mouse model, including tumors induced in vivo, and normal immortalized and transformed alveolar type 2 cells in vitro. Among tumors caused in vivo in Swiss mice by N-nitrosodimethylamine, tumors with and without codon 12 K-ras mutation were discovered. We carried out biochemical analyses to test the hypothesis that mutant K-ras p21 would have higher activity, as indicated by ras-GTP, and that activity of the Erk1/2 pathway leading to increased rate of cell division as marked by proliferating cell nuclear antigen (PCNA) would be observed, with resultant increase in tumor size. The results indicate that the hypothesis is almost certainly incorrect. Tumors with mutant K-ras did not have a significant increase in K-ras p21 or Erk1/2 amount or activity, or amount of PCNA, and in fact these tumors were significantly smaller than those without the mutation, and had less PCNA. The tumors with mutant K-ras, but not the others, showed a significant correlation between K-ras-GTP and both tumor size and total Erk1 and 2 protein. PCNA correlated strongly with amounts of c-raf, but not with K-ras-GTP. TUNEL staining failed to reveal significant apoptosis. These results indicate that mutant ras is playing a role in tumor development other than simply stimulation of mitosis, and influences tumor size via mechanisms other than cell death. Further studies of the role of ras in control of cell growth and differentiation are in progress. - Animal models, Lung alveolar epithelia, Lung cancer, Oncogene, Ras, Renal tumors, Tumor suppressor genes, Tumorigenesis, VHL, - Neither Human Subjects nor Human Tissues

动物和人类肿瘤中的癌基因和肿瘤抑制基因的突变可能会为导致肿瘤的暴露提供重要的线索。对于在病理上与相应的人类癌症相似的啮齿动物肿瘤，啮齿动物疾病可用于对所涉及的细胞事件进行建模并研究预防和治疗。目前，我们专注于肾癌中的von Hippel-Lindau（VHL）基因，以及肺癌中的K-RAS基因。VHL肿瘤抑制基因在家族性和零星肾细胞癌中均具有很大比例的突变。我们最近通过环境致癌物N-亚硝基二甲胺建立了一种用于透明细胞肾脏肿瘤中VHL突变的动物模型。在一项平行研究中，VHL蛋白在培养中的正常大鼠肾细胞中已表达。通过荧光显微镜和免疫元电子显微镜证实的一个显着且意外的发现是PVHL定位于线粒体。鉴于线粒体在细胞因子调节，血管生成和凋亡以及能量代谢中扮演的许多作用，这一发现可能代表了PVHL功能的罗塞塔石。在研究癌基因k-ras在肺腺癌生成中的作用时，我们利用小鼠模型，包括体内诱导的肿瘤，以及正常的永生和转化的肺泡2型细胞体外。在N-亚硝基二甲胺在瑞士小鼠中引起的肿瘤中，发现有或没有密码子12 K-RAS突变的肿瘤。我们进行了生物化学分析，以检验以下假设：突变的K-RAS p21的活性将具有较高的活性，如RAS-GTP所示，ERK1/2途径的活性导致细胞分裂的增加，这是通过增殖细胞核抗原（PCNA）标记的，从而观察到肿瘤大小的增加。结果表明该假设几乎肯定是不正确的。具有突变体K-RAS的肿瘤的K-RAS P21或ERK1/2量或活性或PCNA量没有显着增加，实际上这些肿瘤明显小于没有突变的肿瘤，并且PCNA较少。具有突变K-RAS但没有突变的肿瘤在K-Ras-GTP与肿瘤大小与总ERK1和2蛋白之间显示出显着的相关性。 PCNA与C-RAF量密切相关，但与K-Ras-GTP无关。 Tunel染色未显示出明显的细胞凋亡。这些结果表明，突变体RA在肿瘤发育中发挥作用，而不是简单地刺激有丝分裂，并通过细胞死亡以外的机制影响肿瘤大小。进一步研究RA在控制细胞生长和分化中的作用正在进行中。 - 动物模型，肺肺泡上皮，肺癌，癌基因，RAS，肾脏肿瘤，肿瘤抑制基因，肿瘤发生，VHL， - 人类受试者也不是人体组织