Biologic and therapeutic relevance of DNMT3A mutations in acute myeloid leukemia

急性髓系白血病 DNMT3A 突变的生物学和治疗相关性

• 批准号: 8716708
• 负责人: Olga A Guryanova
• 金额: $ 9.79万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-07 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8716708
• 关键词: Acute Myelocytic Leukemia; Address; Adoptive Transfer; Affect; Affinity; Alleles; Amino Acids; Apoptosis; Apoptotic; Award; Binding; Cells; ChIP-seq; Clinic; Clinical Oncology; Cytotoxic agent; DNA; DNA Binding; DNA Damage; DNA Methylation; DNA Methyltransferase; DNA Modification Methylases; Development; Diagnostic; Dimerization; Disease; Dissociation; Exhibits; Failure; Family; Gene Expression; Genes; Genetic; Genomic Instability; Genotoxic Stress; Goals; Health; Hematopoiesis; Hematopoietic; Hematopoietic Neoplasms; In Vitro; Knock-in Mouse; Malignant - descriptor; Malignant Neoplasms; Mediating; Medicine; Mentors; Molecular; Mutation; Myelogenous; Oncogene Activation; Outcome; Pathogenesis; Pathway interactions; Patients; Pattern; Phase; Phenotype; Play; Population; Property; Reactive Oxygen Species; Recurrence; Recurrent disease; Research; Research Proposals; Resistance; Resistance development; Role; Sampling; Series; Somatic Mutation; Specificity; Staging; Stem cells; Stress; Therapeutic; Time; Translating; Work; adverse outcome; anticancer research; attenuation; base; cancer therapy; career; chemotherapy; design; genome sequencing; genome wide methylation; improved; in vivo; in vivo Model; insight; irradiation; leukemia; leukemogenesis; mouse model; mutant; novel; pre-clinical; preclinical study; prognostic; repaired; research study; response; self-renewal; stem; therapeutic development; translational study

DESCRIPTION (provided by applicant): Biologic and therapeutic relevance of DNMT3A mutations in acute myeloid leukemia Despite the many new advances in cancer research and treatment, therapeutic resistance remains the core challenge in clinical oncology. Genome sequencing efforts have made possible the identification of genes and specific mutations associated with therapeutic failure in the clinic. However, the molecular basis of therapeutic resistance remains largely enigmatic. Recurrent DNMT3A mutations are detected in 25-30% of acute myeloid leukemia (AML) patients and are associated with adverse outcome and resistance to frontline chemotherapy. DNMT3A mutations most often affect amino acid residue R882, and recent work has shown that these mutants display decreased enzymatic activity and aberrant binding properties. In addition, previous studies have shown that increased expression of DNMT3A functions as a pro-apoptotic switch in response to genotoxic stress. We hypothesized that DNMT3A mutations protect cells from apoptosis in response to DNA damage caused by oncogene activation, or by ionizing irradiation (IR) or chemotherapeutics, allowing for the survival of malignant hematopoietic cells. Our preliminary studies show that expression of the AML-associated DNMT3A mutants in primary hematopoietic cells inhibits myeloid differentiation, with accumulation of stem/progenitor cells, reduces apoptosis and increases self-renewal in vitro. In addition, cells harboring mutant DNMT3A exhibited hallmarks of genomic instability. Our mechanistic studies point at impaired DNA damage response including attenuation of p53 activation. This research proposal outlines a three-tiered approach to the comprehensive characterization of the role for DNMT3A mutations in normal and leukemic hematopoiesis and therapeutic resistance. First, we will use adoptive transfer approach in vivo studies and ex vivo studies to assess the contribution of leukemia-associated DNMT3A mutants to alterations in differentiation, apoptosis, and self-renewal in different stem/progenitor cell populations. Next, the molecular mechanisms underlying etiologic role of mutant DNMT3A in AML pathogenesis will be explored. We will address the changes in DNA methylation patterns and DNA binding in DNMT3A-mutant cells through genome-wide methylation profiling and ChIP-seq studies, and perform detailed analysis of DNA damage sensing, response and repair in cells with and without DNMT3A mutations. These studies will be initiated during the mentored phase, and will continue into the independent stage of the award, when the main focus will shift to pre-clinical development of mechanistically-informed anti-leukemic treatments. These functional, mechanistic and pre-clinical studies will be carried out in a novel genetic mouse model expressing leukemia-associated Dnmt3a mutant from its native locus. Overall we posit that genetic alterations in the DNMT3A gene play an important role in development of AML in many patients, and a more thorough understanding of this phenomenon is likely to have eventual diagnostic, prognostic and therapeutic implications.

描述（由申请人提供）：急性髓样白血病中DNMT3A突变的生物学和治疗相关性，尽管癌症研究和治疗方面取得了许多新的进步，但治疗耐药性仍然是临床肿瘤学的核心挑战。基因组测序工作使诊断基因和与治疗性衰竭相关的特异性突变成为可能。但是，治疗抗性的分子基础在很大程度上仍然是神秘的。在25-30％的急性髓样白血病（AML）患者中检测到复发性DNMT3A突变，并且与不良预后和对前线化学疗法的抗性有关。 DNMT3A突变通常会影响氨基酸残基R882，最近的工作表明，这些突变体显示出降低的酶活性和异常结合特性。此外，先前的研究表明，DNMT3A的表达增加是响应遗传毒性应激的促凋亡转换。我们假设DNMT3A突变可保护细胞免受因癌基因激活或通过电离照射（IR）或化学治疗剂的电动损伤而凋亡的细胞凋亡，从而允许恶性造血细胞的存活。我们的初步研究表明，在原代造血细胞中与AML相关的DNMT3A突变体的表达抑制了髓样分化，随着茎/祖细胞的积累，降低了凋亡并增加体外自我更新。此外，具有突变体DNMT3A的细胞表现出基因组不稳定性的标志。我们的机械研究表明，DNA损伤反应受损，包括p53激活的衰减。该研究提案概述了一种三层方法，用于在正常和白血病造血和治疗性抗性中综合表征DNMT3A突变的作用。首先，我们将在体内研究中使用收养转移方法和体内研究来评估白血病相关的DNMT3A突变体对不同茎/祖细胞种群中分化，凋亡和自我更新的改变的贡献。接下来，将探索突变体DNMT3A在AML发病机理中的病因作用的分子机制。我们将通过全基因组甲基化分析和CHIP-seq研究来解决DNMT3A突变细胞中DNA甲基化模式的变化和DNA结合的变化，并对具有和没有DNMT3A突变的细胞中的DNA损伤感应，响应和修复进行详细分析。这些研究将在指导阶段启动，并将继续进入奖项的独立阶段，届时主要重点将转向机械知识的抗白血病治疗的临床前发展。这些功能性，机械性和临床前研究将在一种新型的遗传小鼠模型中进行，该模型从其天然基因座表达与白血病相关的DNMT3A突变体。总体而言，我们认为DNMT3A基因的遗传改变在许多患者中在AML的发展中起重要作用，并且对这种现象的更彻底的了解可能具有最终的诊断，预后和治疗意义。