Molecular Pathogenesis of Acute Myeloid Leukemia

急性髓系白血病的分子发病机制

• 批准号: 9126480
• 负责人: TIMOTHY J. LEY
• 金额: $ 91.5万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-13 至 2022-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9126480
• 关键词: Acute Myelocytic Leukemia; Binding; Cell physiology; Cells; ChIP-seq; Chromatin; DNA; DNA Methylation; Data; Development; Disease; Disease model; Dominant-Negative Mutation; Educational process of instructing; Epigenetic Process; Event; FLT3 gene; Genes; Genomics; Goals; Health; Hematopoietic; Hematopoietic Neoplasms; Histones; Lead; Leukemic Cell; Modeling; Molecular; Mutation; Oncogenes; Pathogenesis; Pathway interactions; Patients; Population; Proteins; Proteomics; RARA gene; Small RNA; Stem cells; Techniques; Therapeutic; Transgenic Mice; Work; bisulfite sequencing; genome sequencing; histone modification; human embryonic stem cell; inhibitor/antagonist; mutant; novel strategies; novel therapeutics; stem; targeted treatment; therapeutic target; transcriptome sequencing; tumor; whole genome

 DESCRIPTION (provided by applicant): In this proposal, we will attempt to determine the precise molecular mechanisms by which acute myeloid leukemia (AML)-initiating mutations act, and to exploit these mechanisms therapeutically. The vast majority of patients who develop AML still die from their disease. New therapies that are more efficacious and less toxic are urgently needed. Recent AML genome sequencing studies have taught us that virtually all AML tumors are clonally heterogeneous. Each tumor originates from a founding clone that was created by an initiating mutation that allowed a single hematopoietic stem/progenitor cell (HSPC) to achieve a clonal advantage. This `preleukemic' clone acquires additional, cooperating mutations that lead to the development of a founding clone, and clinically apparent AML. Subclones arise from the founding clone, or can evolve from other subclones. Regardless, all subclones contain the founding clone mutations. Although cooperating mutations are often attractive for targeted therapies (e.g. FLT3 and/or IDH1/2 inhibitors), they are sometimes found in subclones (i.e. they are only in a fraction of the total leukemic cell population); therapeutic targeting of subclones cannot be expected to be curative. The central hypothesis of this work is that a complete understanding of the consequences of initiating mutations is required to fully understand AML pathogenesis. We also hypothesize that therapeutic approaches directed against initiating mutations are the most likely to provide long-term benefit for AML patients. We will fully characterize two common, well-validated AML-initiating mutations (PML-RARA and DNMT3A R882H) that are both associated with profound epigenetic alterations in hematopoietic cells. We will utilize state-of-the-art techniques (including comprehensive, strand-specific RNA-seq of large and small RNAs, whole genome bisulfite sequencing, chromatin accessibility studies, and ChIP-seq studies for oncogene binding and histone modifications) to pinpoint the key genomic targets of these initiating mutations, and unbiased proteomic techniques to comprehensively identify proteins that interact specifically with the mutant proteins. We will integrate these data to identify genes, RNAs, loci, and pathways that are altered by the initiating mutations, and develop new hypotheses regarding mechanisms that may be relevant for AML pathogenesis. We will model AML-initiating mutations and downstream pathways both in human embryonic stem cells, and in transgenic mice expressing PML-RARA or DNMT3A R882H, to fully explore the contributions of pathways (e.g. DNA methylation and/or histone modifiers) and/or cooperating mutations that may be critical for their actions. As a translational goal of thi work, we will attempt to develop a novel drug that will inhibit the action of the mutant DNMT3A R882H protein, which acts as a dominant negative inhibitor of WT DNMT3A, thereby suppressing de novo DNA methylation in HSPCs. This mutation causes in focal, canonical, DNA hypomethylation, an event that may be reversed by an effective inhibitor, which may restore normal HSPC function.

 描述（由适用提供）：在此提案中，我们将尝试确定急性髓细胞性白血病（AML）启动突变的精确分子机制，并探索这些机制理论。发展AML的绝大多数患者仍然死于疾病。迫切需要更有效且毒性较小的新疗法。最近的AML基因组测序研究告诉我们，几乎所有AML肿瘤都是cloneal的异质性。每个肿瘤源自由启动突变产生的创始克隆，该突变使单个造血茎/祖细胞（HSPC）获得克隆优势。这种“统计学”克隆获得了额外的合作突变，从而导致创始克隆的发展和临床明显的AML。子克隆来自创始克隆，或者可以从其他子克隆中演变。无论如何，所有子克隆都包含创建克隆突变。尽管合作的突变通常对靶向疗法（例如FLT3和/或IDH1/2抑制剂）有吸引力，但有时在亚克隆中发现它们（即它们仅占白血病总细胞群的一小部分）；不能预期靶向亚克隆的治疗靶向。这项工作的核心假设是，我们还需要完全理解启动突变的后果，我们还将假设直接针对启动突变的治疗方法最有可能为AML患者提供长期益处。我们将充分表征两个常见的，验证的AML启动突变（PML-RARA和DNMT3A R882H），它们都与造血细胞的深刻表观遗传改变有关。我们将利用最先进的技术（包括大小的大型和小RNA的全面的，特定的RNA-Seq，整个基因组亚硫酸盐测序，染色质可及性研究以及癌基因结合和组蛋白修饰的CHIP-SEQ研究），以确定这些启动的突变蛋白质构成蛋白质的关键基因组蛋白质构成蛋白质的基因组构成蛋白质，并确定该蛋白质的基因组蛋白质构成蛋白质的基因组蛋白质，并突变蛋白。我们将集成这些数据以识别通过启动而改变的基因，RNA，基因座和途径 突变，并提出有关可能与AML发病机理有关的机制的新假设。我们将在人类胚胎干细胞中以及表达PML-RARA或DNMT3A R882H的转基因小鼠中对AML发射突变和下游途径进行建模，以充分探索途径的贡献（例如DNA甲基化和/或组蛋白修饰符）和/或或/或或/或合作突变，这些突变可能对他们的作用至关重要。作为这项工作的转化目标，我们将尝试开发一种新型药物，该药物将抑制突变体DNMT3A R882H蛋白的作用，该蛋白充当WT DNMT3A的主要负抑制剂，从而抑制HSPC中的DE NOVO DNA甲基化。该突变导致局灶性，规范，DNA低甲基化，这一事件可能会被有效的抑制剂逆转，该抑制剂可能会恢复正常的HSPC功能。