Mechanism of ECM regulation of actin nucleation during morphogenesis.

形态发生过程中 ECM 调节肌动蛋白成核的机制。

基本信息

批准号：
8499354
负责人：
Martha C Soto
金额：
$ 28.57万
依托单位：
RBHS-ROBERT WOOD JOHNSON MEDICAL SCHOOL
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：
2009-07-15 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8499354
关键词：
Actins Address Affect Animal Model Animals Antibodies Architecture Axon Caenorhabditis elegans Cancer Detection Cancerous Cell Polarity Cell membrane Cells Cloning Colorectal Cancer Complex Cues Cytoskeleton Defect Development Disease model ECM receptor Embryo Enhancers Ensure Epithelial Extracellular Matrix F-Actin Failure Genes Genetic Genetic Screening Goals Growth Guanosine Triphosphate Phosphohydrolases Homologous Gene Human Human Development Knock-out Knowledge Lead Learning Malignant - descriptor Malignant Neoplasms Malignant neoplasm of lung Melanoma Cell Modeling Molecular Morphogenesis Movement Mus Mutation Neoplasm Metastasis Neuroblastoma Neurons Phenotype Process Proteins Public Health Receptor Signaling Recruitment Activity Regulation Research Design Role Signal Pathway Signal Transduction Testing Tissues abstracting anticancer research axonal guidance blastomere structure cancer cell cell motility clinically relevant extracellular human disease insight metastatic colorectal migration mouse model mutant neuroblast polarized cell prevent receptor research study

项目摘要

Project Summary/Abstract The growth and spread of cancerous cells requires alterations in cell polarity, and in the organization of the actin cytoskeleton. While our studies have identified complexes that control the actin cytoskeleton, we now need to determine how these actin nucleation complexes are polarized during development. We are identifying extracellular cues and components of signaling pathways that regulate the ability of these complexes to organize cytoskeletal polarity and initiate migrations. Using knockout mutants in a model organism, C. elegans, we have shown that loss of the GTPase CED-10/Rac1, any component of the actin nucleating Arp2/3 complex, or of its activator, the WAVE/SCAR complex, results in the same phenotype: failure in embryonic cell migrations, morphogenesis and altered epithelial polarity. We refer to the actin nucleation cassette encoded by Rac1- WAVE/SCAR-Arp2/3 as the GEX (GTPase/Enhancer of nucleation/actin nucleation eXecution) complex. Mammalian homologs of GEX molecules are misregulated in cancers. For example, WAVE2 is misexpressed in malignant human lung cancers and metastatic colorectal cancers (Semba et al. 2006; Iwaya et al. 2007). However, how these actin nucleation proteins are misregulated during metastasis is not understood. We have determined that some extracellular matrix (ECM) axonal guidance molecules, in addition to their role in axons, affect embryonic migrations, and they regulate the levels of GEX proteins. Objective/Hypothesis: We hypothesize that ECM signals regulate cytoskeletal polarity by recruiting, stabilizing, and/or activating GEX actin nucleation complexes in specific regions of cells. We propose to identify the guidance cues and to analyze how these upstream signals activate the GEX components to initiate migrations. Specific Aims: (1) To determine whether extracellular matrix receptors regulate actin nucleation. (2)To determine which tissues are sending and receiving the signals that lead to cell migrations in the embryo. (3) To use targeted genetics to identify new regulators of the GEX complex. Study design: In Aim 1 we determine the role of ECM receptors in polarized F-actin enrichment, and test if ECM receptors require the GEX complex to affect actin enrichment during morphogenesis. In Aim 2 we determine the architecture of tissue signaling by testing which tissues require the activity of GEX and ECM components during morphogenetic movements. In Aim 3 we identify new regulators of embryonic cell migrations by molecularly cloning new gex mutants. Clinical relevance: The ability of cancer cells to migrate is strongly correlated with malignant progression and metastasis. The human homolog of one of the genes we have identified in C. elegans, WAVE3, is down regulated in neuroblastomas and a mutation in WAVE3 has been connected to neuroblastoma and to changes in the actin cytoskeleton. Our studies may identify genetic targets for cancer detection and provide mechanistic insight into metastasis.

项目概要/摘要癌细胞的生长和扩散需要细胞极性的改变，肌动蛋白细胞骨架的组织。虽然我们的研究已经确定了复合物控制肌动蛋白细胞骨架，我们现在需要确定这些肌动蛋白如何成核复合体在发育过程中是极化的。我们正在识别细胞外线索调节这些复合物组织能力的信号通路的组成部分细胞骨架极性并启动迁移。在模型生物体中使用敲除突变体，线虫，我们已经证明 GTPase CED-10/Rac1 的丢失，肌动蛋白成核 Arp2/3 复合体或其激活剂 WAVE/SCAR 复合体导致相同的表型：胚胎细胞迁移失败、形态发生和改变上皮极性。我们指的是由 Rac1-编码的肌动蛋白成核盒 WAVE/SCAR-Arp2/3 作为 GEX（GTP 酶/成核增强子/肌动蛋白成核执行）复杂。 GEX 分子的哺乳动物同源物在癌症。例如，WAVE2 在人类恶性肺癌中错误表达，转移性结直肠癌（Semba 等人，2006 年；Iwaya 等人，2007 年）。然而，这些如何肌动蛋白成核蛋白在转移过程中的失调尚不清楚。我们有确定一些细胞外基质（ECM）轴突引导分子，除了它们在轴突中的作用，影响胚胎迁移，并调节 GEX 的水平蛋白质。目的/假设：我们假设 ECM 信号通过以下方式调节细胞骨架极性：在特定区域招募、稳定和/或激活 GEX 肌动蛋白成核复合物细胞。我们建议确定指导线索并分析这些上游如何信号激活 GEX 组件以启动迁移。具体目的：（1）确定细胞外基质受体是否调节肌动蛋白成核。 (2)确定哪些组织正在发送和接收导致的信号影响胚胎中的细胞迁移。 (3) 利用靶向遗传学来识别新的调控因子 GEX 综合体。研究设计：在目标 1 中，我们确定 ECM 受体在极化 F-肌动蛋白富集，并测试 ECM 受体是否需要 GEX 复合物来影响形态发生过程中肌动蛋白的富集。在目标 2 中，我们确定组织的结构通过测试哪些组织需要 GEX 和 ECM 成分的活性来发出信号形态发生运动。在目标 3 中，我们确定了胚胎细胞的新调节因子通过分子克隆新的 gex 突变体进行迁移。临床相关性：癌细胞的迁移与恶性进展和转移密切相关。我们在秀丽隐杆线虫中鉴定出的基因之一 WAVE3 的人类同源物是在神经母细胞瘤中下调，WAVE3 的突变与神经母细胞瘤和肌动蛋白细胞骨架的变化。我们的研究可能会识别遗传癌症检测的目标并提供对转移的机制洞察。