Molecular mechanisms of myeloid suppressor genes on chromosome 5

5号染色体骨髓抑制基因的分子机制

• 批准号: 8997482
• 负责人: MICHELLE M LE BEAU
• 金额: $ 36.14万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-01 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8997482
• 关键词: 17p; 5q32; Acute Myelocytic Leukemia; Alkylating Agents; Anemia; Apoptosis; Bone Marrow; Bone Marrow Cells; CSNK1A1 gene; Cell Therapy; Cells; Characteristics; Chromosome abnormality; Chromosomes, Human, Pair 5; Chromosomes, Human, Pair 7; Collaborations; Cytotoxic Chemotherapy; DNA Sequence Alteration; Deaminase; Development; Disease; Drug resistance; Dysmyelopoietic Syndromes; Erythropoiesis; Ethylnitrosourea; Event; Frequencies; Genes; Genetic; Genomics; Goals; Health; Hematopoiesis; Hematopoietic; Hematopoietic stem cells; Human; Induced Mutation; Lead; Lesion; Lysine; Macrocytic Anemia; Maintenance; Malignant - descriptor; Maps; Modeling; Molecular; Monocytosis; Mus; Mutation; Myelogenous; Myeloid Leukemia; Myeloproliferative disease; Pancytopenia; Pathogenesis; Pathway interactions; Patients; Pattern; Play; Pronormoblasts; Regulatory Pathway; Resources; Role; Staging; Stem cells; Suppressor Genes; TP53 gene; Tumor Suppressor Genes; Work; arm; base; cellular targeting; chromosome 5q loss; chromosome 7q loss; cytotoxic; in vivo Model; insight; leukemia; leukemogenesis; loss of function; mouse model; novel therapeutics; outcome forecast; preclinical study; stem; stem cell therapy; transcription factor; treatment strategy

DESCRIPTION (provided by applicant): Therapy-related myeloid neoplasms (t-MNs) are late complications of cytotoxic therapy typically for primary malignant diseases. Heterozygous deletions of the long arm of chromosome 5, del(5q), are frequently noted in t-MN following cytotoxic treatment with alkylating agents, and are associated with loss or mutations of TP53. To identify a leukemia-related gene on chromosome 5, we previously delineated a 970 kb commonly deleted segment (CDS) of 5q31.2, and identified the first haploinsufficient myeloid suppressor gene within this CDS, EGR1. We also identified APC as another haploinsufficient myeloid suppressor gene on 5q. We developed an Mx1-Cre+ Apcfl/+-inducible model, and showed that Apc is essential for the maintenance and survival of hematopoietic stem and progenitor cells (HSPCs). Apcdel/+ mice develop a severe macrocytic anemia, recapitulating characteristic features of t-MN with a del(5q). Notably, concordant haploinsufficiency for Egr1 and Apc cooperates to accelerate anemia onset. We showed that cell intrinsic loss of Tp53 in HSPCs haploinsufficient for Egr1 and Apc led to the development of an aggressive AML in mice, representing the first mouse model for human del(5q) AML. We hypothesize that 5q contains one or more additional myeloid suppressor genes (cis mutations) that cooperate with EGR1 and APC haploinsufficiency, and that additional cooperating mutations (trans mutations) are required for leukemogenesis. The overall goal of this project is to identify cooperating mutations and genetic pathways leading to alkylating agent-induced t-MN with a del(5q). Through collaborations, we will compare genetic pathways identified by genomic analysis of t-MN patients and mouse models for the del(5q), as well as mouse models for the haploinsufficient genes involved in the - 7/del(7q) and loss of 17p, commonly seen together with the del(5q) in t-MN. In Aim 1, we will identify the molecular mechanisms of transformation by EGR1 by characterizing the role of EGR1 in hematopoiesis. Specifically, we will identify the transcriptional targets of EGR1 in HSPCs, and t-MNs with a del(5q), and examine the mechanism by which lesions on 5q and 7q cooperate. In Aim 2, we will identify genetic mutations that cooperate with haploinsufficiency of EGR1 and/or APC in the pathogenesis of myeloid neoplasms by characterizing the genomic pattern of myeloid neoplasms arising in mice with haploinsufficiency for Egr1, Apc, and Tp53, or ENU-treated Egr1+/- mice (an alkylating agent-induced myeloid neoplasm), and by evaluating the cooperative role of candidate myeloid suppressor genes on 5q, e.g., CSNK1A1, SPRY4, and the lysine specific deaminase, KDM3B. In conducting this work, we will generate genetically accurate and tractable in vivo models for preclinical studies, providing critical resources for investigating the fundamental problem of drug resistance in t-MN. Establishing the genetic pathways leading to t-MN may inform the development of biologically-based treatment strategies.

描述（由申请人提供）：治疗相关性髓系肿瘤（t-MNs）是细胞毒性治疗的晚期并发症，通常用于原发性恶性疾病。5号染色体长臂del（5q）的杂合缺失在t-MN中经常被注意到，在用烷基化剂进行细胞毒性治疗后，这与TP53的缺失或突变有关。为了鉴定5号染色体上的白血病相关基因，我们先前描绘了5q31.2的970 kb常见缺失片段（CDS），并在该CDS中鉴定了第一个单倍不足髓系抑制基因EGR1。我们还发现APC是5q上另一个单倍不足的髓系抑制基因。我们建立了Mx1-Cre+ Apcfl/+诱导模型，结果表明Apc对造血干细胞和祖细胞（HSPCs）的维持和存活至关重要。Apcdel/+小鼠出现严重的大细胞性贫血，重现了t-MN的特征（5q）。值得注意的是，Egr1和Apc的一致性单倍性不足共同加速了贫血的发生。我们发现，在Egr1和Apc单倍不足的HSPCs中，细胞固有的Tp53缺失导致小鼠发生侵袭性AML，这是人类del(5q) AML的第一个小鼠模型。我们假设5q含有一个或多个额外的髓细胞抑制基因（顺式突变），这些基因与EGR1和APC单倍不全合作，并且额外的合作突变（反式突变）是白血病发生所必需的。该项目的总体目标是确定协同突变和遗传途径，导致烷基化剂诱导的t-MN与del（5q）。通过合作，我们将比较t-MN患者基因组分析确定的遗传途径和小鼠模型的del(5q)，以及小鼠模型中与t-MN中del（5q）和- 7/del（7q）和17p缺失相关的单倍不足基因，这些基因通常与del（5q）一起出现。在Aim 1中，我们将通过描述EGR1在造血中的作用来确定EGR1转化的分子机制。具体来说，我们将确定HSPCs中EGR1的转录靶点，以及带有del（5q）的t-MNs，并研究5q和7q病变合作的机制。在Aim 2中，我们将通过描述EGR1、APC和Tp53单倍不足小鼠或enu处理的EGR1 +/-小鼠（烷基化剂诱导的髓系肿瘤）发生髓系肿瘤的基因组模式，以及评估5q上候选髓系抑制基因（如CSNK1A1、SPRY4和赖氨酸特异性脱氨酶KDM3B）的协同作用，确定在髓系肿瘤发病机制中与EGR1和/或APC单倍不足合作的基因突变。在开展这项工作的过程中，我们将为临床前研究生成基因准确且易于处理的体内模型，为研究药物的基本问题提供关键资源