A model system to study the tumor suppressor APC

研究肿瘤抑制因子APC的模型系统

• 批准号: 8703122
• 负责人: Mark A. Peifer
• 金额: $ 25.89万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8703122
• 关键词: APC gene; Adenomatous Polyposis Coli; Adult; Animals; Basic Science; Biochemical; Biological; Biological Models; Buffers; Cancer Etiology; Cell Shape; Cells; Centrosome; Cessation of life; Chromosomal Instability; Chromosome Segregation; Colon; Colon Carcinoma; Communication; Complex; Cytoskeleton; DNA Damage; Data; Development; Drosophila genus; Ensure; Event; Excision; Funding; Genetic; Genome Stability; Goals; Health; Homeostasis; Human; Malignant Neoplasms; Mitosis; Mitotic; Mitotic Checkpoint; Modeling; Multiprotein Complexes; Mutate; Mutation; Nuclear; Organ; Pathway interactions; Phosphorylation; Play; Process; Proteins; Regulation; Role; Set protein; Signal Pathway; Signal Transduction; Skeleton; Stem cells; Textbooks; Tissues; Translating; Tumor Suppressor Proteins; Ubiquitination; Work; base; clinical application; effective therapy; in vivo; innovation; insight; intercellular communication; interdisciplinary approach; migration; novel; public health relevance; receptor; stem; tool; tumor; tumor progression; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Colon cancer is a major health challenge, ranking as the second leading cause of cancer deaths. Most cases are initiated by mutations in the tumor suppressor Adenomatous polyposis coli (APC). APC is best known as a key negative regulator of the Wnt cell-cell signaling pathway, which shapes cell fates in virtually every tissue and organ, regulates homeostasis of stem cells in several tissues, and is inappropriately activated in many cancers. APC also plays Wnt-independent roles in regulating the cytoskeleton, thus facilitating processes like high-fidelity chromosome segregation, which also are disrupted in cancer. Our lab's long term goal is to determine how APC and its protein partners regulate both Wnt signaling and the cytoskeleton during normal development and homeostasis, and how that process goes wrong in colon and other cancers. Our lab played important roles in defining how APC acts in the "destruction complex", which targets the Wnt effectors sscatenin for ubiquitination and destruction, and also identified APC as a regulator of cytoskeletal events. To do so, we established powerful dual model systems to study this in parallel in intact animals during Drosophila development and in cultured human cells, using a highly multidisciplinary approach combining state-of-the-art genetic, cell biological, and biochemical tools. Understanding mechanisms by which APC and its protein partners regulate both Wnt signaling and the cytoskeleton during normal development will thus advance both basic science and clinical applications. While we now possess textbook models for both Wnt regulation and APCs cytoskeletal function, it is becoming increasingly clear that these paradigms are oversimplified-in fact APC's mechanistic roles in the destruction complex and in cytoskeletal regulation remain largely mysterious. Our work in the past funding period challenged existing hypotheses for APC function in Wnt regulation, including our own, demonstrating that APC does not play essential nuclear roles in Wnt regulation nor does it play an essential role in localizing the destruction complex. Instead, work from our lab and others suggests the innovative hypothesis underlying Aim 1, in which APC regulates a dynamic catalytic cycle of the destruction complex, which is essential for sscatenin transfer to the E3 ubiquitin ligase. In Aim 1 we will define mechanisms by which APC and Axin act in a dynamic destruction complex, identify novel protein partners that regulate the cycle of conformational change, and determine how Wnt signaling alters destruction complex dynamics to turn it off. Our data also suggest textbook views of APC's roles as a cytoskeletal regulator must be significantly modified. We hypothesize APC is not an essential regulator of mitosis, but instead acts to ensure high fidelity chromosome segregation, working as part of a multiprotein complex, and with its action buffered by mitotic checkpoints that can partially compensate for its loss-this underlies Aim 2. In this Aim we will determine how APC and its partners act to regulate centrosome migration and thus ensure high fidelity chromosome segregation, and explore how Chk2 and other checkpoint regulators buffer the errors that occur in its absence.

描述（由申请人提供）：结肠癌是一个主要的健康挑战，是癌症死亡的第二大原因。大多数病例是由肿瘤抑制因子腺瘤性息肉病大肠（APC）突变引起的。APC作为Wnt细胞-细胞信号通路的关键负调控因子而闻名，Wnt细胞-细胞信号通路在几乎所有组织和器官中塑造细胞命运，调节几种组织中干细胞的稳态，并在许多癌症中被不适当激活。APC还在调节细胞骨架中发挥wnt独立的作用，从而促进高保真染色体分离等过程，这些过程在癌症中也被破坏。我们实验室的长期目标是确定APC及其蛋白伙伴在正常发育和体内平衡过程中如何调节Wnt信号和细胞骨架，以及该过程在结肠癌和其他癌症中如何出错。我们的实验室在定义APC如何在“破坏复合体”中发挥重要作用方面发挥了重要作用，该复合体针对Wnt效应物sscenin进行泛素化和破坏，并确定APC是细胞骨架事件的调节剂。为此，我们建立了强大的双模型系统，在果蝇发育期间的完整动物和培养的人类细胞中并行研究这一点，使用高度多学科的方法结合最先进的遗传、细胞生物学和生化工具。了解APC及其蛋白伙伴在正常发育过程中调节Wnt信号和细胞骨架的机制将促进基础科学和临床应用。虽然我们现在拥有Wnt调控和APCs细胞骨架功能的教科书模型，但越来越清楚的是，这些范式过于简化了