Targeting Cdc42 in leukemia stem cells

靶向白血病干细胞中的 Cdc42

• 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
• 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

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.

摘要 这个项目的目标是使用遗传手段来证明Rho GTP酶， CDC42构成了白血病干细胞(LSCs)的一个新靶点，并应用了一种铅 Cdc42的药理抑制剂抑制人血中CDC42活性的解除调节 干细胞恶性肿瘤。Cdc42信号轴位于许多信号的十字路口 事件和CDC42与许多相关效应器之间的功能相互作用 调节多种生理反应，包括肌动蛋白细胞骨架重组， 造血干/祖细胞的黏附、迁移、存活和增殖。CdC42有 被认为通过生长因子信号来调节RAS的转化 并将细胞因子信号转导入细胞核，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靶向抑制白血病干细胞黏附和植入，促进LSC 在小鼠模型中，从骨髓动员，并诱导LSC凋亡。我们有 还生成并建立了一系列重要的试剂、老鼠模型和 方法学包括条件基因靶向小鼠模型，人类 干细胞/祖细胞转化的急性髓系白血病异种移植模型 一种铅的Cdc42活性特异性抑制剂Casin，能够特异性地抑制 血祖细胞中的CDC42活性与CDC42突变重组/异种移植 确定即时信号通路调控需求的加回法 由Cdc42。在这个提议中，我们将检验这样的假设，即Cdc42对于 干细胞在骨髓间充质干细胞的维持，并代表了治疗的新靶点 根除白血病。我们将：(1)从遗传学角度确认CDC42作为小鼠急性髓系白血病的靶点 通过有条件的基因打靶和突变重组方法的发病和进展； (2)研究CDC42基因敲除对人急性髓系白血病的作用及其分子机制 在人源化小鼠模型中的进展；以及(3)应用CDC42特定的抑制剂， 酪蛋白对小鼠异种骨中人AML白血病干细胞的动员作用 并检验酪蛋白与常规药物的联合作用。 化疗药物对急性髓系白血病干细胞的根除作用。我们的研究可能牵连到 CDC42作为细胞内信号流的关键节点参与多种刺激 白血病干细胞在骨髓中的维持。其结果将直接影响到 CDC42在LSCs中的药理靶向可能允许更多的治疗价值 有效的联合化疗，以努力根除白血病。