The Role of the CBFB-MYH11 Complex in Leukemia Maintenance

CBFB-MYH11 复合物在白血病维持中的作用

• 批准号: 10599919
• 负责人: Ricia Katherine Hyde
• 金额: $ 37.31万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10599919
• 关键词: Acute Myelocytic Leukemia; Address; Affect; Allogenic; Apoptosis; Binding; Biology; Bone Marrow; CBFB gene; CBFbeta-MYH11 fusion protein; Cells; Chimeric Proteins; Chromosomal Rearrangement; Chromosome 16; Chromosome inversion; Clinical; Co-Immunoprecipitations; Combined Modality Therapy; Complex; Core-Binding Factor; DNA; DNA Binding; Dasatinib; Development; Disease; Drug Targeting; Event; Family; Family member; Gene Expression; Gene Fusion; Genes; Genetic; Genetic Transcription; Goals; Growth; HDAC1 gene; Hematopoiesis; Hematopoietic Stem Cell Transplantation; Hematopoietic stem cells; Heterodimerization; High Dose Chemotherapy; Histone Deacetylase Inhibitor; In Vitro; Knock-in Mouse; Leukemic Cell; Life; MYH11 gene; Maintenance; Malignant Neoplasms; Modeling; Molecular; Molecular Target; Mus; Mutate; Mutation; Myelogenous; Myeloid Cells; Oncogenes; Outcome; Pathway interactions; Patient-Focused Outcomes; Patients; Perception; Pharmaceutical Preparations; Prognostic Marker; Protein Tyrosine Kinase; Proteins; RUNX1 gene; Recurrence; Relapse; Repression; Role; Testing; Toxic effect; Transcriptional Activation; Tumor Suppressor Genes; Work; acute myeloid leukemia cell; chimeric gene; cofactor; driver mutation; experience; experimental study; fusion gene; gain of function; hematopoietic differentiation; improved; improved outcome; in vivo; inhibitor; insight; knock-down; leukemia; mouse model; neoplastic; new therapeutic target; novel; novel therapeutics; patient derived xenograft model; pharmacologic; protein complex; relapse patients; side effect; small hairpin RNA; standard care; therapy outcome; tool; transcription factor

ABSTRACT The long-term goal of our lab is to understand the role of the Core Binding Factor (CBF) family of transcription factors in acute myeloid leukemia (AML). CBF family members, which include RUNX1 and its binding partner CBFB, are the most frequently mutated genes in leukemia. One of the most common recurrent CBF mutations is the fusion gene CBFB-MYH11 (CM), which is generated by of the inversion of chromosome 16 [inv(16)]. Expression of CM is the initiating event in AML development, but additional cooperating mutations, such as activating mutations in the tyrosine kinase KIT, are required for transformation to a frank leukemia. CM is assumed to also be required after the acquisition of cooperating mutations, but its role during leukemia maintenance is currently poorly understood. CM was originally thought to dominantly repress RUNX1, leading to the repression of tumor suppressor genes. Our recent work supports a new model of the fusion protein’s activity: CM and RUNX1 together activate transcription of pro-leukemic genes. This new model implies that identifying the functionally important targets genes of the fusion protein complex may lead to new potential drug targets. Another extension of this new model is that there may be additional co-factors required for CM’s transcriptional activity. In recent work, we found that Histone Deacetylase 1 (HDAC1) is part of the CM/RUNX1 complex, and is required for expression of CM target genes. Using a mouse model of inv(16) AML, we found that the HDAC1 inhibitor entinostat induced differentiation, and reduced leukemic burden in vivo. Based on our previous work, we hypothesize that CM is required for the expression of genes that promote leukemia maintenance, and that HDAC1 is an important co-factor of CM. Consequently, we propose that HDAC1 inhibitors will be particularly useful for the treatment of inv(16) AML. In Specific Aim 1, we will use two complimentary approaches to define the role of CM in leukemia maintenance: a new knockin mouse model that allows for deletion of the fusion gene after leukemia development, and an inducible shRNA knockdown model. We will use these tools to determine CM’s role during leukemia maintenance in vivo, if CM independent cells can give rise to relapse, and test the role of candidate CM target genes in leukemia maintenance. In Specific Aim 2, we will determine the requirement for HDAC1 in CM+ leukemia cells, test whether HDAC1 affects expression of both CM target and non-target genes, and test potential mechanisms for HDAC1’s non-canonical role in transcriptional activation. Specific Aim 3 will test the potential of the entinostat to treat inv(16) AML. We will use genetic and patient derived xenograft mouse models to test whether the addition of entinostat to the standard treatments will reduce leukemic burden and increase survival. We will also test whether using entinostat to inhibit CM in combination with dasatinib to inhibit cooperating mutations in KIT is more effective than either drug alone. The proposed studies are based on our accumulated experience and our strong preliminary findings, and will address important gaps in the field and have direct translational implications for inv(16) AML patients.

抽象的 我们实验室的长期目标是了解核心结合因子（CBF）家族的作用 急性髓系白血病 (AML) 中的转录因子。 CBF 家族成员，包括 RUNX1 及其 结合伴侣 CBFB 是白血病中最常见的突变基因。最常见的复发性疾病之一 CBF突变是由染色体倒位产生的融合基因CBFB-MYH11(CM) 16 [第(16)]。 CM 的表达是 AML 发展的起始事件，但还有其他协同突变， 例如激活酪氨酸激酶 KIT 中的突变，是转化为明确的白血病所必需的。厘米 被认为在获得协同突变后也是必需的，但它在白血病期间的作用 目前人们对维护知之甚少。 CM 最初被认为显着抑制 RUNX1，导致 来抑制肿瘤抑制基因。我们最近的工作支持融合蛋白的新模型 活性：CM 和 RUNX1 一起激活促白血病基因的转录。这个新模型意味着 鉴定融合蛋白复合物功能上重要的靶基因可能会产生新的潜在药物 目标。这个新模型的另一个扩展是 CM 可能需要额外的辅助因子 转录活性。在最近的工作中，我们发现组蛋白脱乙酰酶 1 (HDAC1) 是 CM/RUNX1 的一部分 复杂，并且是 CM 靶基因表达所必需的。使用 inv(16) AML 小鼠模型，我们发现 HDAC1 抑制剂恩替司他诱导分化，并减少体内白血病负担。 基于我们之前的工作，我们假设 CM 是促进基因表达所必需的 白血病维持，HDAC1 是 CM 的重要辅助因子。因此，我们建议 HDAC1 抑制剂对于治疗 inv(16) AML 特别有用。在具体目标 1 中，我们将使用两个 定义 CM 在白血病维持中的作用的补充方法：一种新的敲入小鼠模型 允许在白血病发生后删除融合基因，并建立可诱导的 shRNA 敲低模型。 我们将使用这些工具来确定 CM 在体内白血病维持过程中的作用，如果 CM 独立细胞 会引起复发，并测试候选 CM 靶基因在白血病维持中的作用。具体来说 目标2，我们将确定CM+白血病细胞对HDAC1的需求，测试HDAC1是否影响 CM 靶基因和非靶基因的表达，并测试 HDAC1 非规范的潜在机制 在转录激活中的作用。具体目标 3 将测试恩替司他治疗 inv(16) AML 的潜力。我们 将使用遗传和患者衍生的异种移植小鼠模型来测试是否将恩替司他添加到 标准治疗将减少白血病负担并提高生存率。我们还将测试是否使用entinostat 抑制 CM 与达沙替尼联合抑制 KIT 协同突变比任一者更有效 单独用药。拟议的研究基于我们积累的经验和强有力的初步发现， 并将填补该领域的重要空白，并对 inv(16) AML 患者产生直接的转化影响。