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）：治疗相关的骨髓肿瘤（t-MN）是细胞毒治疗的晚期并发症，通常用于原发性恶性疾病。在用烷化剂进行细胞毒性治疗后的 t-MN 中，经常注意到 5 号染色体长臂 del(5q) 的杂合缺失，并且与 TP53 的丢失或突变相关。为了鉴定 5 号染色体上的白血病相关基因，我们之前描绘了 5q31.2 的 970 kb 常见缺失片段 (CDS)，并鉴定了该 CDS 内的第一个单倍体不足的骨髓抑制基因 EGR1。我们还鉴定出 APC 是 5q 上的另一个单倍体不足的骨髓抑制基因。我们开发了 Mx1-Cre+ Apcfl/+-诱导模型，并表明 Apc 对于造血干细胞和祖细胞 (HSPC) 的维持和存活至关重要。 Apcdel/+ 小鼠出现严重的大红细胞性贫血，概括了具有 del(5q) 的 t-MN 的特征。值得注意的是，Egr1 和 Apc 的一致单倍体不足共同加速贫血的发生。我们发现，Egr1 和 Apc 单倍体不足的 HSPC 中 Tp53 的细胞内在缺失导致小鼠中发生侵袭性 AML，这代表了第一个人类 del(5q) AML 小鼠模型。我们假设 5q 包含一个或多个与 EGR1 和 APC 单倍体不足相配合的额外骨髓抑制基因（顺式突变），并且白血病发生需要额外的配合突变（反式突变）。该项目的总体目标是确定导致烷化剂诱导的带有 del(5q) 的 t-MN 的协同突变和遗传途径。通过合作，我们将比较通过 t-MN 患者和小鼠模型的基因组分析确定的基因通路的 del(5q)，以及涉及 - 7/del(7q) 和 17p 缺失的单倍体不足基因的小鼠模型，通常与 t-MN 中的 del(5q) 一起出现。在目标 1 中，我们将通过表征 EGR1 在造血中的作用来确定 EGR1 转化的分子机制。具体来说，我们将鉴定 HSPC 和具有 del(5q) 的 t-MN 中 EGR1 的转录靶点，并检查 5q 和 7q 上的损伤协同的机制。在目标 2 中，我们将通过表征 Egr1、Apc 和 Tp53 单倍体不足或 ENU 治疗的小鼠中出现的髓系肿瘤的基因组模式，鉴定与 EGR1 和/或 APC 单倍体不足在髓系肿瘤发病机制中协同作用的基因突变。 Egr1+/- 小鼠（烷化剂诱导的骨髓肿瘤），并通过评估候选骨髓抑制因子的协同作用5q 上的基因，例如 CSNK1A1、SPRY4 和赖氨酸特异性脱氨酶 KDM3B。在开展这项工作时，我们将为临床前研究生成遗传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 t-MN 中的耐药性。建立导致 t-MN 的遗传途径可能有助于制定基于生物学的治疗策略。