MURINE MODELS OF MYELOID MALIGNANCIES

在上一个资助期，我们在评估FLT 3的作用方面取得了重大进展。 AMI中的突变，以及测试FLT 3抑制剂的鼠模型的开发。这些都 包括单独分析FLT 3-ITD表达，以及与协同等位基因， PML-RAR α。与项目1合作，项目2在临床前 通过在小鼠疾病模型中显示疗效开发FLT 3抑制剂，导致阶段 项目5中两种不同FLT 3抑制剂的I期和II期试验。我们计划继续推进 使用条件性敲入等位基因对FLT 3-ITD在白血病发生中的作用的额外研究。在 具体目标1，我们将分析FLT 3-ITD和激活环等位基因的体内活性，并尝试 了解FLT 3-ITD对髓系疾病的相对偏好，以及FLT 3激活 淋巴疾病的环状等位基因我们将使用高速多参数流式细胞术来检测 假设这些等位基因在多能细胞中对细胞命运决定有不同的影响， 祖细胞阶段（LMPP/MPP），其中FLT 3在造血发育期间高度表达。 我们将研究FLT 3-ITD与FLT 3 WT相比是一种有效的激活剂的机制。 STATS在FLT 3的背景下使用突变消除这种活性。在第二阶段，我们将 探索FLT 3-ITD介导疾病的这些精确基因型模型的协同作用 通过与几种互补等位基因杂交，包括C/EBPalpha和MLL融合体， 与项目3和4合作。这些反过来将作为有用的体内模型，用于测试新的 项目1中开发的联合疗法。我们亦会跟进最近的调查结果。 这表明逆转录病毒FLT 3-ITD逆转录病毒整合位点可能有助于 组织蛋白酶G-PML-RAR α协同模型中的AML。在具体目标3中，我们 开发由JAK 2 V617 F等位基因介导的骨髓增生性疾病（MPD）的鼠模型， 我们和其他人最近发现...最后，我们将使用MPD的小鼠模型作为平台， 测试新型JAK 2抑制剂，用于项目5中的临床试验开发。总的来说，这是一个高度 互动项目，将建立在成功和临床前开发的良好记录， 骨髓恶性肿瘤的新疗法。

We have made significant progress during the prior funding period in assessing the role of FLT3 mutations in AMI, and the development of murine models to test FLT3 inhibitors. These have included analysis of FLT3-ITD expression alone, and in combination with cooperating alleles such as PML-RARalpha. Working with Project 1, Project 2 has been instrumental in preclinical development of FLT3 inhibitors by showing efficacy in murine models of disease, resulting in Phase I and Phase II trials of two different FLT3 inhibitors in Project 5. We plan to move forward with additional studies of the role of FLT3-ITD in leukemogenesis using conditional knock-in alleles. In Specific Aim 1, we will analyze the in vivo activity of FLT3-ITD and activation loop alleles, and try to understand the relative predilection of FLT3-ITD for myeloid lineage disease, and of FLT3 activation loop alleles for lymphoid disease. We will use high speed multiparameter flow cytometry to test the hypothesis that these alleles have differential effect on cell fate determination at the multipotent progenitor stage (LMPP/MPP) where FLT3 is highly expressed during hematopoietic development. We will study the mechanism whereby FLT3-ITD, in contrast with FLT3 WT, is a potent activator of STATS using mutations in the context of FLT3 that abrogate this activity. In Specific Aim 2, we will explore cooperating effects of these accurate genotypic models of FLT3-ITD mediated disease through crosses with several complementing alleles including, C/EBPalpha, and MLL fusions, working with Projects 3 and 4. These in turn will serve as useful in vivo models for testing novel combination therapies that are developed in Project 1. We .will also pursue recent findings suggesting that retroviral FLT3-ITD retroviral integration sites may contribute to pathogenesis of AML in the Cathepsin G - PML-RARalpha model of cooperativity. In Specific Aim 3, we will develop murine models of myeloproliferative disease (MPD) mediated by the JAK2V617F allele that we and others have recently identified.. Finally, we will use murine models of MPD as a platform for testing novel JAK2 inhibitors for development of clinical trials in Project 5. Overall, this is a highly interactive Project that will build on a proven track record of success and preclinical development of novel therapies for myeloid malignancies.