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: 8672543
• 负责人: ALLAN BALMAIN
• 金额: $ 45.86万
• 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 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8672543
• 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 Expression; Gene Expression Profiling; Genotype; Goals; Growth; Histologic; Human; In Vitro; Individual; KRAS2 gene; Knock-in Mouse; 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; public health relevance; 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最常见和最致命的人类癌症中，但针对KRAS以治疗目的为目标的努力尚未成功。 KRAS由于替代剪接而产生了两个高度同源的同工型（KRAS4A和KRAS4B）。而小鼠的完整KRAS基因敲除导致胚胎致死性，而Kras4a（Kras4aki）或Kras4b（Kras4bki）的敲除，以替代同工型的牺牲会导致可行的小鼠。 Kras4aki小鼠仅表达KRAS4A和KRAS4BKI小鼠仅表达KRAS4B，这首先可以比较这些Kras同工型在体内转化中的各个角色。我们发现KRAS4BKI小鼠对KRAS突变肺和皮肤肿瘤具有高度抗性，这表明KRAS4A对于2个独立组织中的转化至关重要。我们的研究进一步表明，KRAS4A还负责先前报道的野生型KRAS肿瘤抑制活性。该提案的总体目标是利用这些新型小鼠模型来研究KRAS4A和KRAS4B在肺癌发育中的功能，包括癌基因（突变形式）和肿瘤抑制器（野生型形式）。该提案的一个主要优势是可行的可行菌株独特地表达每种同工型，代表了对这种主要人类癌基因的同工型特定功能进行研究的强大而互补的体内系统。该提案的目标1将使用致癌物诱导的肺癌发生模型研究体内单个KRAS同工型的致癌功能。 AIM 2将研究在有条件活化的突变kras（即Krasla2和KraslSl-G12D）模型中，在体内野生型KRAS4A和KRAS4B的肿瘤抑制活性。 AIM 3将利用从各种小鼠模型中得出的肺上皮细胞系，以详细介绍KRAS4A和KRAS4B信号通路的体外分析，以便对其致癌活性获得机械见解。 AIM 4将评估这些单个KRAS同工型在人类KRAS突变肺癌细胞的生长/维持中的作用。对KRAS的同工型特定功能的见解不仅对理解癌症的发展很重要，而且可能对治疗设计具有重大影响。