Mechanisms of Leukemogenic Transformation by MLL-CALM

MLL-CALM 转化白血病的机制

• 批准号: 7231615
• 负责人: DANIEL STEVEN WECHSLER
• 金额: $ 26.29万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7231615
• 关键词: 11q14; 11q23; Accounting; Acute Myelocytic Leukemia; Acute leukemia; Biological Assay; Biology; Chimeric Proteins; Chromosomal Rearrangement; Chromosomes; Chromosomes, Human, Pair 11; Clathrin; Development; Dimerization; Endocytosis; Gene Targeting; Gene Transfer; Genes; Growth Factor; Growth Factor Receptors; Hematopoiesis; Hematopoietic; Hematopoietic Neoplasms; Hematopoietic stem cells; In Vitro; Infant; Lead; Lymphoid; MLL gene; Membrane Lipids; Modeling; Mus; Mutation; Myeloid Leukemia; Myeloid-Lymphoid Leukemia Protein; Neoplastic Cell Transformation; Numbers; Oncogenic; Pathogenesis; Phenotype; Play; Proteins; Role; Signal Transduction; Transcriptional Regulation; Transgenic Mice; Vesicle; attenuation; in vivo; insight; iron metabolism; leukemia; leukemia/lymphoma; leukemogenesis; novel; progenitor; promoter; retroviral-mediated; trafficking

DESCRIPTION (provided by applicant): Chromosomal rearrangements involving the Mixed Lineage Leukemia (MLL) gene at chromosome 11q23 are frequently seen in leukemias. Although more than 40 translocation partner genes have been identified for MLL, the precise mechanisms by which MLL-fusion partner proteins lead to leukemia remain unclear. We recently identified a novel chromosome 11 inversion in an infant with acute myeloid leukemia (AML) that juxtaposed MLL to the Clathrin Assembly Lymphoid Myeloid Leukemia (CALM) gene at 11q14. CALM was first identified as a translocation partner for AF10 - itself an MLL partner - in acute leukemias and lymphomas. The CALM protein directly interacts with clathrin and membrane lipids, and plays a key role in endocytosis and intracellular vesicle trafficking. Recently, mutations in the murine calm gene have been shown to account for the phenotype of the fill mouse, which has significant abnormalities in hematopoiesis and iron metabolism. The involvement of CALM as a translocation partner for two distinct genes in hematopoietic malignancies, together with its involvement in normal hematopoiesis, suggests that perturbation of normal CALM function contributes to the development of leukemia. The overall objective of this proposal is to study the biology of the MLL-CALM fusion protein in leukemogenesis. We hypothesize that the MLL-CALM translocation contributes to the development of myeloid leukemia by perturbing the normal function of both CALM and MLL. To begin to understand mechanisms by which the MLL-CALM protein is involved in the pathogenesis of AML, our first aim is to determine whether MLL-CALM expression results in transformation in vitro and leukemia in vivo. We will use the murine hematopoietic progenitor transformation assay to rigorously demonstrate that MLL-CALM expression results in transformation in vitro, and establish in vivo murine models of MLL-CALM-dependent leukemia. In addition, to more faithfully mimic the MLL-CALM leukemia phenotype, we will prepare an mll-CALM transgenic mouse. Finally, we will examine leukemogenesis in the context of fit1 -derived hematopoietic precursors. Our second overall aim is to identify mechanisms involved in MLL-CALM-dependent transformation. In these studies, we will focus on the role of three specific mechanisms - dimerization, transcriptional regulation and endocytosis - in MLL-CALM- and CALM-AF10-dependent transformation. Insights gained regarding CALM function may be generalizable to the large number of leukemias and lymphomas with CALM-AF10 translocations, and, in a broader sense, will contribute to our understanding of normal CALM biology.

描述（由申请人提供）：涉及染色体 11q23 处混合谱系白血病 (MLL) 基因的染色体重排在白血病中常见。尽管已鉴定出 40 多个与 MLL 相关的易位伴侣基因，但 MLL 融合伴侣蛋白导致白血病的确切机制仍不清楚。我们最近在一名患有急性髓性白血病 (AML) 的婴儿中发现了一种新的 11 号染色体倒位，该倒位将 MLL 与 11q14 处的网格蛋白组装淋巴髓性白血病 (CALM) 基因并列。 CALM 首次被确定为急性白血病和淋巴瘤中 AF10 的易位伙伴（AF10 本身是 MLL 伙伴）。 CALM 蛋白直接与网格蛋白和膜脂相互作用，在内吞作用和细胞内囊泡运输中发挥关键作用。最近，小鼠平静基因的突变已被证明可以解释填充小鼠的表型，该小鼠在造血和铁代谢方面存在显着异常。 CALM 作为造血系统恶性肿瘤中两个不同基因的易位伙伴，及其参与正常造血功能，表明正常 CALM 功能的扰动有助于白血病的发展。该提案的总体目标是研究 MLL-CALM 融合蛋白在白血病发生中的生物学。我们假设 MLL-CALM 易位通过扰乱 CALM 和 MLL 的正常功能而导致髓细胞性白血病的发生。为了开始了解 MLL-CALM 蛋白参与 AML 发病机制的机制，我们的首要目标是确定 MLL-CALM 表达是否会导致体外转化和体内白血病。我们将使用小鼠造血祖细胞转化实验来严格证明MLL-CALM表达会导致体外转化，并建立MLL-CALM依赖性白血病的体内小鼠模型。此外，为了更忠实地模仿MLL-CALM白血病表型，我们将制备mll-CALM转基因小鼠。最后，我们将在 fit1 衍生的造血前体细胞的背景下检查白血病的发生。我们的第二个总体目标是确定 MLL-CALM 依赖性转化所涉及的机制。在这些研究中，我们将重点关注三种特定机制（二聚化、转录调控和内吞作用）在 MLL-CALM 和 CALM-AF10 依赖性转化中的作用。 关于 CALM 功能的见解可能适用于大量具有 CALM-AF10 易位的白血病和淋巴瘤，并且从更广泛的意义上讲，将有助于我们对正常 CALM 生物学的理解。