Discovering chemical tools for acute myelogenous leukemia

描述(申请人提供)：许多白血病，包括急性髓系白血病(AML)，是由致癌突变引起的，这些突变(1)改变分化和(2)促进多能造血祖细胞的增殖。大多数化疗针对的是大量白血病细胞的增殖，但很少针对多潜能白血病干细胞的分化缺陷。针对白血病干细胞分化的治疗方法的开发一直受到在体外模拟癌基因干扰的细胞命运决定的困难，以及在体内进行高通量小分子筛选的困难。一种模拟癌基因对体内细胞分化影响的系统，同时还能够进行高通量的化学筛选，可能会为针对白血病干细胞分化的治疗打开大门。癌基因AML1-ETO(AE)导致造血祖细胞分化缺陷，导致AML患者粒系原始细胞积聚。在发育中的斑马鱼中表达AE还会扰乱造血祖细胞的分化，导致类似于人类AML患者的粒细胞母细胞的聚集。用表达AE的斑马鱼对2100个小分子进行的中试筛选发现，有三种化合物类别可以阻断AE对造血祖细胞分化的影响。现在提出了一个更大的小分子筛查，希望它能发现更多拮抗AE功能的化合物。已发现的化合物将接受机制研究，并使用人类细胞和急性髓系白血病小鼠模型评估治疗潜力。具体目标如下：目的1.筛选更多的AE拮抗剂。目的2.阐明AE拮抗剂抑制AE功能的机制。目的3.验证AE拮抗剂的治疗效果。通过利用斑马鱼在疾病建模和小分子筛查方面的独特能力，拟议的项目将为解剖导致AML的致癌途径提供强大的工具，并可能指出治疗这种疾病的有前途的新的化疗方法。

DESCRIPTION (provided by applicant): Many leukemias, including acute myelogenous leukemia (AML), are caused by oncogenic mutations that (1) alter differentiation and (2) promote proliferation of multipotent hematopoietic progenitor cells. Most chemotherapies target proliferation of the bulk leukemia cells, but few target the differentiation defects of multipotent leukemia stem cells. Development of therapies that target leukemia stem cell differentiation has been hindered by the difficulties of modeling oncogene-disrupted cell fate decisions in vitro and the difficulties of conducting high-throughput small molecule screens in vivo. A system that models the effects of oncogenes on cell differentiation in vivo while also enabling high-throughput chemical screening could open the door to therapies that target leukemia stem cell differentiation. The oncogene AML1-ETO (AE) causes a differentiation defect in hematopoietic progenitor cells that leads to accumulation of granulocytic blast cells in AML patients. Expression of AE in developing zebrafish also disrupts hematopoietic progenitor cell differentiation, leading to accumulation of granulocytic blast cells resembling those from human AML patients. A pilot screen of 2100 small molecules conducted with AE- expressing zebrafish has identified three compound classes that block the effects of AE on hematopoietic progenitor cell differentiation. A larger small molecule screen is now proposed, with the expectation that it will discover additional compounds that antagonize AE function. Compounds discovered will be subjected to mechanistic studies and evaluated for therapeutic potential using human cells and mouse models of AML. The following specific aims are proposed: Aim 1. Screening for additional AE antagonists. Aim 2. Elucidating the mechanisms by which the AE antagonists suppress AE function. Aim 3. Validating the therapeutic utility of the AE antagonists. By exploiting the unique capabilities of the zebrafish for disease modeling and small molecule screening, the proposed project will provide powerful tools for dissecting the oncogenic pathways leading to AML and may point to promising new chemotherapeutic approaches for treating the disease.