The Oncogenic and Tumor Suppressor Functions of the Kras isoform 4A in vivo

Kras 亚型 4A 体内的致癌和抑癌功能

• 批准号: 9058497
• 负责人: ALLAN BALMAIN
• 金额: $ 47.06万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2017-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9058497
• 关键词: Affect; Alleles; Alternative Splicing; Apoptosis; Biological Assay; Biology; Cancer cell line; Carcinogens; Cell Line; Cell Proliferation; Cells; Cellular Assay; Comparative Study; Data; Development; Embryo; Engineering; Epithelial Cells; Exons; Frequencies; Gene Chips; Gene Expression; Gene Expression Profiling; Genotype; Goals; Growth; Health; Histologic; Human; In Vitro; Individual; KRAS2 gene; Knock-in; Lead; Lung; Lung Neoplasms; Maintenance; Malignant Neoplasms; Malignant neoplasm of lung; Mediating; Minor; Modeling; Molecular; Molecular Analysis; Mus; Mutation; Oncogenes; Oncogenic; Pathway interactions; Phase; Phenotype; Protein Isoforms; Proteins; Ras Signaling Pathway; Reporting; Resistance; Role; Signal Pathway; Signal Transduction; Skin; Skin Neoplasms; Structure of parenchyma of lung; System; Testing; Therapeutic; Time; Tissues; Tumor Burden; Tumor Suppressor Proteins; Urethane; Wild Type Mouse; Xenograft Model; base; cancer cell; carcinogenesis; design; in vivo; inhibitor/antagonist; insight; knockout gene; lung carcinogenesis; mouse model; mutant; novel; success; tumor; tumor growth; tumor initiation; tumor progression

DESCRIPTION (provided by applicant): Activating mutations in KRAS occur frequently in some of the most common and deadliest of human cancers but efforts to target KRAS for therapeutic purposes have not been successful. KRAS generates two highly homologous isoforms (KRAS4A and KRAS4B) as a result of alternative splicing. While the complete Kras gene knockout in mice causes embryonic lethality, knock-in of either Kras4A (Kras4AKI) or Kras4B (Kras4BKI) at the expense of the alternate isoform results in viable mice. Kras4AKI mice express only Kras4A and Kras4BKI mice express only Kras4B, enabling for the first time a comparison of the individual roles of these Kras isoforms in transformation in vivo. We have found that Kras4BKI mice are highly resistant to the development Kras mutant lung and skin tumors, suggesting that Kras4A is essential for transformation in 2 independent tissues. Our studies further showed that Kras4A is also responsible for the previously reported tumor suppressor activity of wild type Kras. The overall goal of this proposal is to exploit these novel mouse models to study the functions of both Kras4A and Kras4B in lung cancer development, both as oncogenes (mutant form) and as tumor suppressors (wild type form). A major strength of this proposal is the availability of viable strains uniquely expressing each isoform, representing powerful and complementary in vivo systems for studies into the isoform specific functions of this major human oncogene. Aim 1 of this proposal will investigate the oncogenic function of individual Kras isoforms in vivo using models of carcinogen induced lung carcinogenesis. Aim 2 will investigate the tumor suppressor activity of wild type Kras4A and Kras4B in vivo in models of conditionally activatable mutant Kras (i.e. KrasLA2 and KrasLSL-G12D). Aim 3 will take advantage of lung epithelial cell lines derived from the various mouse models for detailed in vitro analyses of Kras4A and Kras4B signaling pathways in order to gain mechanistic insights into their oncogenic activities. Aim 4 will evaluate the roles of these individual KRAS isoforms in the growth/maintenance of human KRAS mutant lung cancer cells. Insights into the isoform specific functions of KRAS will not only be important to the understanding of cancer development but could potentially have major implications for therapeutic design.

描述（由申请人提供）：KRAS中的激活突变经常发生在一些最常见和最致命的人类癌症中，但靶向KRAS用于治疗目的的努力尚未成功。由于选择性剪接，KRAS产生两种高度同源的同种型（KRAS 4A和KRAS 4 B）。虽然小鼠中的完全Kras基因敲除导致胚胎致死，但以替代同种型为代价敲入Kras 4A（Kras 4AKI）或Kras 4 B（Kras 4 BKI）导致存活小鼠。Kras 4AKI小鼠仅表达Kras 4A，而Kras 4 BKI小鼠仅表达Kras 4 B，这使得首次能够比较这些Kras同种型在体内转化中的各自作用。我们已经发现Kras 4 BKI小鼠对Kras突变型肺和皮肤肿瘤的发展具有高度抗性，这表明Kras 4A对于两种独立组织中的转化是必需的。我们的研究进一步表明，Kras 4A也负责先前报道的野生型Kras的肿瘤抑制活性。该提案的总体目标是利用这些新的小鼠模型来研究Kras 4A和Kras 4 B在肺癌发展中的功能，无论是作为癌基因（突变形式）还是作为肿瘤抑制因子（野生型形式）。这一建议的主要优势是可获得独特表达每种亚型的活菌株，代表了用于研究这一主要人类致癌基因的亚型特异性功能的强大和互补的体内系统。本研究的第一个目的是利用致癌物诱导的肺癌模型研究Kras亚型在体内的致癌功能。目的2将在条件激活突变型Kras（即KrasLA 2和KrasLSL-G12 D）模型中研究野生型Kras 4A和Kras 4 B的体内肿瘤抑制活性。目的3将利用来自各种小鼠模型的肺上皮细胞系，对Kras 4A和Kras 4 B信号通路进行详细的体外分析，以获得对其致癌活性的机制性见解。目的4将评估这些单独的KRAS亚型在人KRAS突变型肺癌细胞的生长/维持中的作用。深入了解KRAS的亚型特异性功能不仅对理解癌症发展很重要，而且可能对治疗设计产生重大影响。