DNMT3A in Development of Hematologic Malignancies

DNMT3A 在血液恶性肿瘤发展中的作用

• 批准号: 10241920
• 负责人: MARGARET A. GOODELL
• 金额: $ 53.32万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-11 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10241920
• 关键词: Acute Lymphocytic Leukemia; Acute Myelocytic Leukemia; Alleles; Cell Line; Cells; Clustered Regularly Interspaced Short Palindromic Repeats; Collaborations; DNA Methylation; DNA Modification Methylases; DNMT3a; Dependence; Development; Disease; Epigenetic Process; Event; FLT3 gene; Funding; Gene Expression; Genes; Genetic Transcription; Goals; Hematologic Neoplasms; Hematopoiesis; Hematopoietic System; Hematopoietic stem cells; Homeobox Genes; Human; Human Cell Line; Lead; Lymphoid; Malignant Neoplasms; Methylation; Modeling; Molecular; Mus; Mutate; Mutation; Myelogenous; NPM1 gene; Nuclear; Phase; Premalignant Cell; Process; Progress Reports; Sampling; Site; Tumor Suppressor Proteins; Umbilical Cord Blood; Work; Yang; acute myeloid leukemia cell; cell type; dosage; epigenome; epigenomics; human DNA; improved; insight; leukemia; leukemia/lymphoma; mouse model; mutant; novel therapeutic intervention; premalignant; progenitor; protein expression; self-renewal; stem cells; stem-like cell; tumor

Abstract DNA METHYLTRANSFERASE 3A (DNMT3A) has emerged over the past ~8 years as one of the most important tumor suppressors in the hematopoietic system, being mutated across most types of human hematologic malignancies, and found in greater than 20% of acute myeloid leukemias (AMLs) as well as acute lymphoid leukemias (ALLs) and lymphomas. Through mechanisms that are not understood, DNMT3A mutations are thought to provide a fertile ground for secondary mutations which drive the frank malignancy. In the previous funding period, we sought to establish and study a reliable tumor model of DNMT3A-associated malignancies using the recognized collaboration between DNMT3A-mutation and the internal tandem duplication (ITD) of FLT3 which results in highly penetrant malignancies of both myeloid and lymphoid types. Here, we will study the very earliest events that represent the transition from clonal hematopoiesis to malignacy. We hypothesize that DNMT3A mutations and NPM1 mutations collaborate effectively by enforcing complementary epigenetic changes that serve to maintain mutated cells in an HSC-like state. We expect that a key effect of this dysregulation is aberrant expression of HOX genes that drives self- renewal. We will dissect the mechanisms through which this occurs here using mouse models, human cell lines, and human primary samples. Our long-term goal is to use insights developed here to enforce differentiation and develop new therapeutic strategies. We will (1) Identify the epigenetic and molecular changes associated with the development of malignancies from Dnmt3a-deficient hematopoietic progenitors. Using mice that have mutant alleles of Dnmt3a-KO and inducible NPM1c, we will examine the concerted changes that occur at the epigenetic and transcriptional levels in pre-malignant stem and progenitor cells. (2) Examine the dependencies of AML with mutated DNMT3A, NPM1, and FLT3-ITD. We hypothesize this common sub-type of AML is dependent on the sustained expression of particular genes such as Hox and Meis1. We will examine this and other potential dependencies using CRISPR KO or targeted DNA methylation. (3) Examine in human DNMT3A-mutated AML cells epigenome remodeling and dependencies. We will validate targets identified in Aims 1 and 2, and explore the value of specific modulators such as nuclear re- localization of NPM1, correction of the DNMT3A-mutant allele, and re-methylation of specific target sites. These studies will reveal the stepwise epigenomic changes that occur due to loss of DNMT3A that lead to AML as well as some of their dependencies. This will lead to an improved understanding of how loss of DNMT3A promotes malignancies, and potentially to new therapeutic strategies due to identification of new targets.

摘要 DNA甲基转移酶3A（DNMT 3A）是近8年来发现的一种 造血系统中最重要的肿瘤抑制因子，在大多数类型中发生突变 人类血液恶性肿瘤，并发现在超过20%的急性髓性白血病 （AML）以及急性淋巴样白血病（ALL）和淋巴瘤。通过各种机制， 目前还不清楚，DNMT 3A突变被认为为继发性疾病提供了肥沃的土壤 导致恶性肿瘤的突变在上一个融资期，我们试图建立 并使用公认的DNMT 3A相关恶性肿瘤的可靠肿瘤模型进行研究。 DNMT 3A突变和FLT 3的内部串联重复（ITD）之间的协作， 导致骨髓和淋巴类型的高度渗透性恶性肿瘤。在这里，我们将研究 这是代表从克隆造血向克隆生殖转变的最早期事件。我们 假设DNMT 3A突变和NPM 1突变通过强制执行 互补的表观遗传变化，其用于将突变的细胞维持在HSC样状态。我们 预计这种失调的一个关键影响是HOX基因的异常表达，从而驱动自我调节。 退款我们将使用小鼠模型剖析这种情况发生的机制， 人类细胞系和人类原始样本。我们的长期目标是利用 在这里加强分化和开发新的治疗策略。我们将（1）确定 表观遗传和分子变化与恶性肿瘤的发展， Dnmt 3a缺陷型造血祖细胞。使用具有Dnmt 3a-KO的突变等位基因的小鼠 和诱导型NPM 1c，我们将研究发生在表观遗传和 恶性前干细胞和祖细胞中的转录水平。(2)检查依赖项 突变的DNMT 3A、NPM 1和FLT 3-ITD的AML。我们假设这种常见的亚型 AML依赖于特定基因的持续表达，如Hox和Meis 1。我们 我将使用CRISPR KO或靶向DNA来研究这一点和其他潜在的依赖性。 甲基化(3)在人DNMT 3A突变的AML细胞中检查表观基因组重塑和 个依赖项我们将验证目标1和目标2中确定的目标，并探讨具体目标的价值。 调节剂如NPM 1的核再定位，DNMT 3A突变等位基因的校正， 和特定靶位点的再甲基化。这些研究将揭示逐步表观基因组 由于DNMT 3A的丢失而发生的变化导致AML以及它们的一些 个依赖项这将有助于更好地理解DNMT 3A的缺失如何促进 恶性肿瘤，并可能由于新靶点的鉴定而产生新的治疗策略。