Oncogenic role of PIK3CA hotspot mutations

PIK3CA 热点突变的致癌作用

基本信息

批准号：
7752583
负责人：
Ramon E Parsons
金额：
$ 33.33万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-01-01 至 2013-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7752583
关键词：
1-Phosphatidylinositol 3-Kinase AKT1 gene Address Alleles Amino Acids Animals Apoptosis Biological Assay Biopsy Breast Carcinoma Cancer Model Cells Chickens Codon Nucleotides Complement DNA Data Development Disease Dissection ERBB2 gene Embryo Enzymes Epithelial Cells Event Excision Exons Experimental Models Family Fibroblasts Gene Expression Genes Genetic Histopathology Human IGF1R gene Immunohistochemistry In Vitro Knock-in Mouse Laboratories Lead Malignant Neoplasms Mammary Neoplasms Mammary Tumorigenesis Mammary gland Mediating Missense Mutation Modification Molecular Mouse Strains Mus Mutant Strains Mice Mutate Mutation NIH 3T3 Cells Nude Mice Oncogenes Oncogenic PIK3CA gene PTEN gene Pathway interactions Patients Pattern Phenotype Phosphotransferases Point Mutation Positioning Attribute Premalignant Process Protein Binding Proto-Oncogene Proteins c-akt Research Research Personnel Resistance Role Running Signal Pathway Signal Transduction Simulate Specificity Suppressor Genes Therapeutic Therapeutic Intervention Tissues Treatment Protocols Tumor Markers Tumor Suppressor Genes base cancer microarray cancer therapy cell transformation cell type combinatorial comparative enzyme activity experience gain of function genetic analysis human PIK3CA protein lysylglutamic acid malignant breast neoplasm mammary epithelium migration mouse model mutant neoplastic cell overexpression programs public health relevance ras Oncogene research study simulation tumor tumor initiation tumor progression tumorigenesis tumorigenic

项目摘要

DESCRIPTION (provided by applicant): A research program is proposed to investigate in mammary cells the tumorigenic consequences of PIK3CA mutations by using a powerful combination of genetic analyses in mouse models and human cells aiming to address mechanistic questions. The PIK3CA gene (encoding the catalytic p110-alpha subunit of PI3-kinase) is one of the most frequently mutated oncogenes in human cancer. In fact, ~30% of breast carcinomas harbor heterozygous non-random (hotspot) gain-of-function PIK3CA missense mutations present in the segments encoding either the helical or the kinase domain of the enzyme (most frequently E545K and H1047R, respectively). Although both of these mutations increase the kinase enzymatic activity, upregulate the downstream AKT pathway, and promote cell transformation upon overexpression, in human tumors they do not act alone and are associated with molecular changes in other genes. In fact, we have found based upon our examination of human tumor biopsies that that each of the hotspots appears to have shared and in some cases distinct collaborators in the oncogenic process. Therefore, instead of overexpression experiments, it is proposed for an unbiased study of common and unique mutational consequences to simulate the situation in human breast tumors by introducing E545K and H1047R mutations into the endogenous gene by a knock-in approach. The oncogenic consequences of activating the mutations in the mammary epithelium will be assessed by generating mouse mutants expressing conditionally each of the two Pik3ca hotspot mutations. Similar knock-in mutants in human mammary cells will also be studied. Genetic relationships with the downstream oncogene Akt1 and the candidate collaborating partners PTEN, HER2/Erbb2 and IGF1R will then be investigated. In parallel, the immediate consequences of the same PIK3CA mutations will be evaluated in pre-malignant mouse mammary epithelium and immortal human mammary epithelial cells, and will be examined for alterations in signaling, gene expression and cell phenotypes, and compared to tumors. PUBLIC HEALTH RELEVANCE: PIK3CA is the most commonly mutated oncogene in human breast cancer, and mutations of PIK3CA have been shown to increase its enzymatic activity. Considering that PIK3CA is an outstanding candidate for cancer therapy, the proposed projects are timely and important for the identification of deregulated oncogenic pathways collaborating with mutated PIK3CA to drive malignant tumor progression. This information on candidate targets for therapeutic intervention would be crucial for the eventual development of strategies aiming to optimize targeted, combinatorial treatment regimens.

描述（由申请人提供）：拟开展一项研究计划，通过在小鼠模型和人类细胞中使用遗传分析的强大组合来研究乳腺细胞中 PIK3CA 突变的致瘤后果，旨在解决机制问题。 PIK3CA 基因（编码 PI3 激酶的催化 p110-alpha 亚基）是人类癌症中最常见突变的癌基因之一。事实上，约 30% 的乳腺癌存在杂合非随机（热点）功能获得性 PIK3CA 错义突变，存在于编码酶的螺旋结构域或激酶结构域的片段中（最常见的是 E545K 和 H1047R）。尽管这两种突变都会增加激酶酶活性，上调下游 AKT 通路，并在过度表达时促进细胞转化，但在人类肿瘤中，它们并不单独起作用，而是与其他基因的分子变化相关。事实上，根据对人类肿瘤活检的检查，我们发现每个热点似乎在致癌过程中都有共同的合作者，在某些情况下还有不同的合作者。因此，建议不要进行过表达实验，而是通过敲入的方法将E545K和H1047R突变引入内源基因来模拟人类乳腺肿瘤的情况，对常见和独特的突变后果进行公正的研究。将通过生成有条件表达两个 Pik3ca 热点突变中每一个的小鼠突变体来评估激活乳腺上皮突变的致癌后果。人类乳腺细胞中类似的敲入突变体也将被研究。然后将研究与下游癌基因 Akt1 以及候选合作伙伴 PTEN、HER2/Erbb2 和 IGF1R 的遗传关系。与此同时，将在恶变前的小鼠乳腺上皮和永生的人类乳腺上皮细胞中评估相同 PIK3CA 突变的直接后果，并检查信号传导、基因表达和细胞表型的变化，并与肿瘤进行比较。公共健康相关性：PIK3CA 是人类乳腺癌中最常见的突变癌基因，PIK3CA 的突变已被证明会增加其酶活性。考虑到 PIK3CA 是癌症治疗的杰出候选者，拟议的项目对于识别与突变 PIK3CA 合作驱动恶性肿瘤进展的放松管制的致癌途径是及时且重要的。有关治疗干预候选目标的信息对于最终制定旨在优化针对性组合治疗方案的策略至关重要。