The Role of CHAF1B in Maintaining Malignant Leukemia Stem Cells

CHAF1B 在维持恶性白血病干细胞中的作用

• 批准号: 10163137
• 负责人: Andrew Volk
• 金额: $ 19.52万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10163137
• 关键词: Acute Megakaryocytic Leukemias; Acute Myelocytic Leukemia; Acute Promyelocytic Leukemia; Acute leukemia; Advisory Committees; Affect; Automobile Driving; Award; Binding; CEBPA gene; Cancer Center; Cell Line; Cells; ChIP-seq; Child; Chromatin; Chromatin Modeling; Chromosome 21; Collaborations; Complex; DNA replication fork; Data; Data Set; Deposition; Diagnosis; Differentiated Gene; Differentiation Therapy; Down Syndrome; Enhancers; Gene Expression; Genes; Genetic Transcription; Goals; Growth; Hematologic Neoplasms; Hematopoietic; Hematopoietic Neoplasms; Home; Human; In Vitro; Institution; Leukemic Cell; MLL-AF9; Maintenance; Malignant - descriptor; Malignant Neoplasms; Mediating; Mentors; Modeling; Mus; Mutation; Myelogenous; Myeloid Leukemia; Myeloproliferative disease; Nature; Nucleosomes; Outcome; Patients; Phase; Phenotype; Predisposition; Process; Prognosis; Proteins; Proteomics; Reagent; Reporting; Research; Research Personnel; Risk; Role; S Phase; Sampling; TP53 gene; The Cancer Genome Atlas; Therapeutic; Training; Transcription Coactivator; Undifferentiated; Universities; WD Repeat; acute myeloid leukemia cell; base; cancer cell; career; effective therapy; experience; experimental study; genetic signature; genomic locus; in vivo; knock-down; leukemia; leukemic stem cell; leukemogenesis; member; myeloid leukemia cell; next generation sequence data; novel; novel therapeutic intervention; overexpression; post-doctoral training; programs; promoter; small molecule; therapeutic target; therapy design; tool; transcription factor; transient myeloproliferative disorder; tumor

PROJECT SUMMARY Children with Down syndrome (DS) are at substantial risk of developing acute leukemia, which suggests that there are leukemia promoting genes on chromosome 21. Chromatin Assembly Factor 1B (CHAF1B), which resides in the DS critical region, is a member of the heterotrimeric CAF1 chromatin assembly complex that is responsible for depositing H3/H4 heterodimers at the replication fork during S-phase. CHAF1B levels are elevated in DS-AML patient samples, as well as non-DS AML cell lines and primary AML samples when compared to healthy samples. While elevated expression is associated with poor prognosis in most tumors, the mechanism by which CHAF1B promotes leukemogenesis is unknown. My preliminary data show that CHAF1B directly binds discrete regions of chromatin associated with promoters and enhancers of myeloid differentiation genes. Deletion of Chaf1b in myeloid leukemia cells results in replacement of CHAF1B on the chromatin with the pro-differentiation transcription factors including CEBPA and the subsequent activation of a myeloid differentiation transcriptional program. Therefore, I propose that CHAF1B is required to maintain the undifferentiated state of MLL-AF9 leukemic cells through a role as a transcriptional regulator. In this proposal, I will study the mechanism of CHAF1B-dependent maintenance of leukemic stem cells. The central hypothesis is CHAF1B maintains the undifferentiated state of myeloid leukemic cells by competing for chromatin occupancy with transcription factors at the promoters and enhancers of differentiation genes. This competition leads to reduced expression of these genes and the resulting maintenance of the leukemic blast phenotype. In Aim 1, I will explore the mechanism of how the different domains of the CHAF1B protein contribute to maintaining the undifferentiated state of myeloid leukemic cells. Then, in Aim 2, I will establish CHAF1B as a therapeutic target in AML (including DS-AML) by determining its contribution to the progression of hematologic tumors in vivo and primary human patient samples in vitro. My ultimate goal is to use the information gained during the K99/R00 award to develop novel small molecule compounds that can block CHAF1B function and control AML tumors in vivo by differentiation. My career goal is to become an independent investigator and leader in the field of chromatin assembly and its effects on hematopoietic malignancies with the ultimate goal of developing new therapeutic strategies to treat leukemia. During the mentored K99 phase, my main technical goal is to become proficient at analysis of large-scale NGS data sets and basic proteomics. The impact of the K99 phase will be enhanced by my collaborations with Dr. Scott Armstrong at Dana Farber Cancer Center at Harvard University and Dr. Yubin Ge at Wayne State University, by allowing me to expand my training outside my home institution of Northwestern University. Dr. John Crispino and my advisory team will guide me through the completion of my postdoctoral training and assist me with my transition to independence.

项目摘要 唐氏综合症（DS）的儿童有急性白血病的巨大风险，这表明 有白血病在21染色体上促进基因。染色质组装因子1b（CHAF1B） 驻留在DS关键区域，是异三聚体CAF1染色质组装复合物的成员 负责在S期间在复制叉处沉积H3/H4异二聚体。 CHAF1B水平是 当DS-AML患者样品以及非DS AML细胞系和主要AML样品中升高 与健康样本相比。虽然表达升高与大多数肿瘤的预后不良有关，但 CHAF1B促进白血病发生的机制尚不清楚。我的初步数据表明CHAF1B 直接结合与启动子和骨髓分化增强子相关的染色质区域 基因。髓样白血病细胞中CHAF1B的删除导致在染色质上替代CHAF1B 促分化的转录因子，包括CEBPA和随后的髓样激活 分化转录程序。因此，我建议需要CHAF1B维护 MLL-AF9白血病细胞的未分化状态通过作为转录调节剂的角色。在这个建议中，我 将研究CHAF1B依赖性维持白血病细胞的机制。中心假设是 CHAF1B通过竞争染色质占用来维持髓样白血病细胞的未分化状态 在启动子和分化基因增强子的转录因子。这场比赛导致 这些基因的表达降低以及白血病爆炸表型的维持。 在AIM 1中，我将探讨CHAF1B蛋白不同域如何贡献的机制 维持髓样白血病细胞的未分化状态。然后，在AIM 2中，我将建立CHAF1B作为一个 通过确定其对血液学进展的贡献，AML（包括DS-AML）中的治疗靶标 体内肿瘤和原发性人类患者样品体外样品。我的最终目标是使用获得的信息 在K99/R00奖中，开发新型的小分子化合物，可以阻止CHAF1B功能和 通过分化在体内控制AML肿瘤。我的职业目标是成为独立的调查员和领导者 在染色质组装领域及其对造血恶性肿瘤的影响，是最终目标 制定新的治疗策略来治疗白血病。在指导的K99阶段，我的主要技术 目标是精通大规模NGS数据集和基本蛋白质组学的分析。的影响 我与Dana Farber癌症中心的Scott Armstrong博士的合作将增强K99阶段 哈佛大学和韦恩州立大学的Yubin GE博士，允许我在外面扩展培训 我的西北大学的家庭机构。约翰·克里斯皮诺（John Crispino）博士和我的顾问团队将指导我通过 我的博士后培训完成，并帮助我过渡到独立。