Targeting Cdc42 in leukemia stem cells

靶向白血病干细胞中的 Cdc42

基本信息

批准号：
8433225
负责人：
JAMES C MULLOY
金额：
$ 28.95万
依托单位：
CINCINNATI CHILDRENS HOSP MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-03-10 至 2015-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8433225
关键词：
Actins Acute Myelocytic Leukemia Adhesions Affect Apoptosis Back Binding Biochemical Biological Blood Bone Marrow CD34 gene Cell Adhesion Cell Maintenance Cell Nucleus Cell Proliferation Cell physiology Cells Collection Cytokine Signaling Cytoskeletal Modeling Cytoskeleton Defect Engraftment Event F-Actin Family Future Gene Deletion Gene Targeting Genetic Goals Growth Factor Receptors Guanosine Triphosphate Phosphohydrolases Hematopoietic Stem Cell Mobilization Hematopoietic stem cells Homing Human In Vitro Integrins Knock-out Lead Leukemic Cell MLL-AF9 Maintenance Malignant Neoplasms Maps Mediating Methodology Methods Modeling Molecular Mus N-ras Genes Nodal Pathologic Pathway interactions Physiological Play Reagent Resistance Retroviridae Role Signal Pathway Signal Transduction Stem cells Stimulus Testing Therapeutic Translating Transplantation Ursidae Family Work Xenograft Model Xenograft procedure abstracting anti-cancer therapeutic chemotherapy combinatorial inhibitor/antagonist leukemia leukemic stem cell leukemogenesis migration mouse model mutant new therapeutic target novel novel therapeutics progenitor reconstitution residence response rho rho GTP-Binding Proteins small hairpin RNA stem therapeutic target

项目摘要

Abstract The goals of this project are to use genetic means to demonstrate that the Rho GTPase, Cdc42 constitutes a novel target in leukemia stem cells (LSCs), and to apply a lead pharmacologic inhibitor of Cdc42 to suppress deregulated Cdc42 activity in human blood stem cell malignancies. The Cdc42 signaling axis lies at the crossroads of many signaling events and the functional interaction between Cdc42 and many of its implicated effectors mediate a variety of physiological responses including actin cytoskeletal reorganization, adhesion, migration, survival, and proliferation, of blood stem/progenitor cells. Cdc42 has been suggested to mediate Ras-transformation by signaling through growth factor receptors and to transduce cytokine signals into the nucleus to impact on cell proliferation. In the preliminary results, we have built up a basic conceptual framework suggesting that Cdc42 targeting can inhibit leukemia stem cell adhesion and engraftment, promote LSC mobilization from the bone marrow, and induce LSC apoptosis, in mouse models. We have also generated and established a collection of important reagents, mouse models, and methodologies including a conditional gene targeted mouse model, a human stem/progenitor transformed acute myeloid leukemia xenograft model in "humanized" mice, a lead Cdc42-activity specific inhibitor, CASIN, that is capable of specifically suppressing Cdc42 activity in blood progenitors, and Cdc42 mutant reconstitution/xenotransplantation add-back methods in defining the requirement of immediate signaling pathways regulated by Cdc42. In this proposal, we will test the hypothesis that Cdc42 is essential for the maintenance of LSCs in the BM niche and represents a novel therapeutic target for leukemia eradication. We will (1) genetically validate Cdc42 as a target in murine AML onset and progression by conditional gene targeting and mutant reconstitution approaches; (2) determine the effect and molecular mechanisms of Cdc42 knockdown on human AML progression in a humanized mouse model; and (3) apply the Cdc42-specific inhibitor, CASIN, to mobilization of human AML leukemia stem cells from xenograft mouse bone marrow and examine the combinatorial effect of CASIN together with the conventional chemotherapy agents on AML leukemia stem cell eradication. Our studies may implicate Cdc42 as a critical nodal of intracellular signal flows from multiple stimuli involved in leukemia stem cell maintenance in the bone marrow niche. The results will bear direct therapeutic value that pharmacologic targeting of Cdc42 in LSCs may allow for more effective combinatory chemotherapy in the effort to eradicate leukemia.

抽象的该项目的目标是利用遗传手段证明 Rho GTPase， Cdc42构成白血病干细胞（LSC）的新靶点，并应用先导 Cdc42 药物抑制剂可抑制人血液中失调的 Cdc42 活性干细胞恶性肿瘤。 Cdc42 信号轴位于许多信号的十字路口事件以及 Cdc42 与其许多相关效应器之间的功能相互作用介导多种生理反应，包括肌动蛋白细胞骨架重组，造血干细胞/祖细胞的粘附、迁移、存活和增殖。 Cdc42 有有人建议通过生长因子信号传导来介导 Ras 转化受体并将细胞因子信号转导至细胞核以影响细胞增殖。在初步结果中，我们建立了一个基本的概念框架，表明 Cdc42靶向可抑制白血病干细胞粘附和植入，促进LSC 在小鼠模型中，从骨髓中动员并诱导 LSC 凋亡。我们有还生成并建立了一系列重要的试剂、小鼠模型和方法包括条件基因靶向小鼠模型、人类在“人源化”小鼠中干细胞/祖细胞转化的急性髓系白血病异种移植模型，一种主要的 Cdc42 活性特异性抑制剂 CASIN，能够特异性抑制血液祖细胞中的 Cdc42 活性以及 Cdc42 突变体重建/异种移植定义立即信号通路调节要求的回加方法由 Cdc42 提供。在本提案中，我们将检验 Cdc42 对于维持 BM 生态位中的 LSC 并代表了新的治疗靶点消灭白血病。我们将 (1) 从基因角度验证 Cdc42 作为小鼠 AML 的靶点通过条件基因靶向和突变体重建方法发生和进展； (2)确定Cdc42敲低对人类AML的影响和分子机制人源化小鼠模型中的进展； (3)应用Cdc42特异性抑制剂， CASIN，从异种移植小鼠骨中动员人类 AML 白血病干细胞深入骨髓并检查 CASIN 与常规药物的组合效果化疗药物对 AML 白血病干细胞的根除作用。我们的研究可能暗示 Cdc42 作为细胞内信号流的关键节点，涉及多种刺激白血病干细胞在骨髓生态位中的维持。结果将直接影响 LSC 中 Cdc42 的药理靶向可能带来更多治疗价值有效的联合化疗努力根除白血病。