An unexpected signaling output for the tumor suppressor APC

肿瘤抑制因子 APC 的意外信号输出

基本信息

批准号：
9504746
负责人：
PETER S KLEIN
金额：
$ 8.29万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-16 至 2020-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9504746
关键词：
APC gene Adenomatous Polyposis Coli Adult Animal Model Apoptosis Binding Biopsy Cancer Etiology Cells Colon Carcinoma Colorectal Cancer Complex Cyclin D1 Data Development Drosophila genus Embryo Embryonic Development FRAP1 gene Gastrointestinal Polyp Gene Targeting Genetic Genetic Models Glycogen Synthase Kinase 3 Human Impairment Intestines Lead Link Malignant neoplasm of gastrointestinal tract Maps Mediating Modeling Molecular Genetics Mus Mutate Mutation Neoplasms Nuclear Nutrient Output Pathway interactions Patients Pharmacology Phenotype Phosphorylation Play Point Mutation Polyps Proliferation Marker Raptors Recruitment Activity Recurrence Regulation Role Signal Pathway Signal Transduction Study models TSC2 gene Testing Tissues Tuberous sclerosis protein complex Tumor Suppressor Genes Tumor Suppressor Proteins WNT Signaling Pathway Zebrafish adenoma beta catenin c-myc Genes cell type genetic approach in vitro activity in vivo in vivo Model loss of function mutant neoplastic novel novel strategies novel therapeutics polyposis response sensor tumor tumorigenesis

项目摘要

Summary This proposal identifies a new function for Adenomatous polyposis coli (APC), a tumor suppressor and negative regulator of Wnt signaling. Homozygous loss of APC causes polyposis and colon cancer in humans and deletion in early embryos causes multiple developmental phenotypes in model organisms such as Drosophila, zebrafish, and mouse. Apc mutations cause accumulation of ß-catenin, which activates Wnt target genes such as c-myc and cyclin D1. However, nuclear ß-catenin is not detectable in early adenomas of patients with germline APC mutations (familial adenomatous polyposis (FAP)) nor in the developing intestines of apc mutant zebrafish, suggesting that additional effectors are required downstream of APC. We find that APC directly enhances the activity of glycogen synthase kinase-3 (GSK-3), providing an unexpected mechanism for APC-dependent suppression of multiple downstream targets, including the nutrient sensor mTOR (mechanistic Target of Rapamycin) and ß-catenin. APC mutations reduce GSK-3 activity, thereby activating mTORC1 in diverse in vivo settings including adenomas from patients with FAP, intestinal adenomas in mice, and apc mutant zebrafish embryos. Our overall hypothesis is that APC directly activates GSK-3 and that this signaling motif regulates multiple pathways, including ß-catenin and mTOR signaling. This model reveals a critical, new function for APC, provides a mechanism for mTOR activation caused by APC mutations, and suggests a link between APC and other signaling pathways that are independent of Wnt/ß-catenin. In aim 1 of this proposal, we will map the GSK-3 activation domain of APC. In aim 2, we will explore the mechanism of mTOR regulation by APC in vivo, including FAP patients. Aim 3 explores the surprising observation that apc mutation causes a dramatic neoplastic phenotype in zebrafish within 3 days that requires mTOR activation. We will use molecular and genetic approaches in zebrafish to characterize these tumors as a highly accessible, in vivo model to explore APC signaling and tumorigenesis.

概括该提案确定了腺瘤性结肠息肉病 (APC) 的新功能，它是一种肿瘤抑制因子和 Wnt 信号传导的负调节因子 APC 纯合性缺失会导致人类息肉病和结肠癌。早期胚胎的缺失会导致模型生物体出现多种发育表型，例如果蝇、斑马鱼和小鼠的 Apc 突变会导致 β-连环蛋白的积累，从而激活 Wnt 靶标。然而，在早期腺瘤中检测不到核β-连环蛋白。具有种系 APC 突变（家族性腺瘤性息肉病 (FAP)）或发育中肠道的患者 apc 突变斑马鱼，表明 APC 下游需要额外的效应器。 APC 直接增强糖原合成酶激酶 3 (GSK-3) 的活性，提供意想不到的效果 APC 依赖性抑制多个下游靶标（包括营养物传感器）的机制 mTOR（雷帕霉素的机械靶标）和 ß-连环蛋白突变会降低 GSK-3 活性。在多种体内环境中激活 mTORC1，包括 FAP 患者的腺瘤、肠腺瘤在小鼠和 apc 突变斑马鱼胚胎中，我们的总体假设是 APC 直接激活 GSK-3。该信号基序调节多种途径，包括 ß-catenin 和 mTOR 信号传导。该模型揭示了 APC 的一个关键新功能，提供了由以下因素引起的 mTOR 激活机制： APC 突变，并表明 APC 与其他独立的信号通路之间存在联系在本提案的目标 1 中，我们将绘制 APC 的 GSK-3 激活结构域。探索 APC 体内 mTOR 调节机制，包括 FAP 患者的 Aim 3 探索。令人惊讶的观察结果是，apc 突变在 3 天内导致斑马鱼出现戏剧性的肿瘤表型我们将使用斑马鱼的分子和遗传学方法来表征。这些肿瘤作为一种易于获取的体内模型来探索 APC 信号传导和肿瘤发生。