Regulators of ubiquitin signaling in malignant hematopoiesis

恶性造血中泛素信号传导的调节因子

• 批准号: 9654305
• 负责人: Madeline Niederkorn
• 金额: $ 3.87万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-07 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9654305
• 关键词: Acute Myelocytic Leukemia; Affect; Allogenic; Binding Proteins; Biochemical; Biological Assay; Biology; Cancer Biology; Case Study; Catalytic Domain; Cell Line; Cell physiology; Cells; Chemicals; Chromosome abnormality; Chromosomes; Clone Cells; Complex; DNA Damage; Data; Development; Disease; Disease Progression; Drug Targeting; Drug Utilization; Dysmyelopoietic Syndromes; Dysplasia; Event; Exhibits; FHA Domain; Familiarity; Family member; Foundations; Genes; Genetic; Genetic study; Genotoxic Stress; Goals; Hematopoiesis; Hematopoietic Neoplasms; Hematopoietic stem cells; Human; Hypersensitivity; Immune; Immune signaling; Impairment; In Vitro; Individual; Investigation; MDM2 gene; MLL-AF9; Malignant - descriptor; Malignant Neoplasms; Modeling; Molecular; Mus; Myelogenous; Oncogenes; Oncogenic; Pathogenesis; Pathway interactions; Patients; Peptide Hydrolases; Phase; Phenotype; Positioning Attribute; Postdoctoral Fellow; Preleukemia; Proteomics; RUNX3 gene; Regulation; Reporting; Repression; Research; Research Personnel; Signal Transduction; Stem cell transplant; Stress; Structure; TP53 gene; TRAF-Interacting Protein; TRAF6 gene; Testing; Therapeutic; Toll-like receptors; Training; Ubiquitin; Work; Xenograft procedure; base; chromosome 5q loss; curative treatments; cytopenia; drug development; drug discovery; druggable target; genotoxicity; high risk; in vivo; ineffective therapies; lead candidate; leukemia; member; mouse model; novel; novel drug class; novel therapeutics; outcome forecast; pressure; prevent; progenitor; programs; response; screening; small molecule inhibitor; stressor; therapeutic target; therapy development; transcriptome sequencing

Project Summary / Abstract Myelodysplastic syndromes (MDS) are heterogeneous clonal hematopoietic stem and progenitor cell (HSPC) disorders with frequent transformation to acute myeloid leukemia (AML). Molecular events leading to AML transformation are poorly defined and the only curative therapy is allogeneic stem cell transplantations, for which few patients are eligible. One of the reasons for ineffective treatments is the lack of understanding of the mechanisms of disease. Therefore, investigations into the cellular and molecular basis of genetically- defined MDS and AML subtypes are crucial to the development of novel therapies. Deletions on chromosome (chr) 5q (del5q) are the most frequent cytogenetic abnormality in MDS and are indicative of poor prognosis in AML. However, the functions of individual genes within del(5q) are largely unexplored. We recently reported that TRAF-interacting protein with forkhead-associated (FHA) domain B (TIFAB) is deleted in all reported cases of del(5q) MDS/AML and its deletion in mice results in phenotypes reminiscent of human MDS, due partly to aberrant innate immune signaling via TRAF6 activation; but, we also observed increases in p53 activity. To fully elucidate the mechanism of TIFAB-dependent regulation of p53, we performed a proteomics screen for TIFAB-binding proteins. Ubiquitin-specific peptidase 15 (USP15), a deubiquitinase that stabilizes MDM2 and enforces p53 degradation, emerged as the lead candidate. Therefore, we devised a multi-pronged approach in which we first, characterized the TIFAB-dependent p53 activity in our Tifab-deficient MDS model (Aim 1A), and second, uncovered the molecular mechanism of the TIFAB-USP15 complex in regulating p53 (Aim 1B). Our findings garnered rationale for defining the function of USP15 in established malignant hematopoiesis, which is well underway and which we propose to complete during the F99 phase of this research program (Aim 1C). Our preliminary data indicate that USP15 is highly expressed in AML and is important for leukemic progenitor function, but not normal HSPCs. We will employ a combination of in vivo and in vitro approaches using our Usp15-/- model, MLL-AF9 leukemia models, and AML cell lines to elucidate the function of USP15 in AML. In completing my dissertation research, I have acquired a strong foundation in mouse genetics, murine models, hematopoietic malignancies including MDS and AML, cancer biology, and cellular mechanisms. I have learned biochemical assays, structure-function studies, and genetic studies, while gaining familiarity with screening approaches including RNA-sequencing and proteomics. With my comprehensive training, I am positioned and highly motivated to pursue a post-doctoral research direction elucidating the determinants of USP15 activity, while utilizing drug discovery platforms to develop small- molecule inhibitors against this druggable target (Aim 2).

项目总结/摘要 骨髓增生异常综合征（MDS）是一种异质性克隆性造血干/祖细胞（HSPC） 经常转化为急性髓性白血病（AML）的疾病。导致AML的分子事件 转化定义不清，唯一的治愈性治疗是异基因干细胞移植， 符合条件的患者寥寥无几治疗无效的原因之一是缺乏了解 疾病的机制。因此，对遗传学的细胞和分子基础的研究- 确定的MDS和AML亚型对于开发新疗法至关重要。染色体缺失 (chr)5 q（del 5 q）是MDS中最常见的细胞遗传学异常，并且指示MDS患者的不良预后。 急性髓细胞白血病然而，del（5 q）中单个基因的功能在很大程度上尚未探索。我们最近报道 TRAF相互作用蛋白与叉头相关（FHA）结构域B（TIFA B）在所有报道的缺失 小鼠中的del（5 q）MDS/AML及其缺失导致的表型使人联想到人类MDS，这是由于 部分原因是通过TRAF 6激活的异常先天免疫信号传导;但是，我们也观察到p53 活动为了充分阐明TIFAB依赖性调节p53的机制，我们进行了蛋白质组学研究。 筛选TIFAB结合蛋白。泛素特异性肽酶15（USP 15），一种稳定 MDM 2和强制p53降解，成为主要候选者。因此，我们设计了一个多管齐下的 在该方法中，我们首先表征了TIFAB缺陷型MDS模型中TIFAB依赖性p53活性 (Aim第二，揭示了TIFAB-USP 15复合物调节p53的分子机制 (Aim 1B）。我们的研究结果为确定USP 15在已建立的恶性肿瘤中的功能提供了理论依据。 造血，这是正在进行中，我们建议在F99阶段完成， 研究计划（Aim 1C）。我们的初步数据表明USP 15在AML中高度表达， 对白血病祖细胞功能很重要，但对正常HSPC不重要。我们将采用体内和 使用我们的Usp 15-/-模型、MLL-AF 9白血病模型和AML细胞系的体外方法来阐明 USP 15在AML中的作用。在完成我的论文研究，我已经获得了坚实的基础， 小鼠遗传学、鼠模型、造血系统恶性肿瘤（包括MDS和AML）、癌症生物学，以及 细胞机制。我学过生化分析、结构功能研究和遗传研究， 熟悉筛选方法，包括RNA测序和蛋白质组学。和我 经过全面的培训，我定位并高度积极地追求博士后研究方向 阐明USP 15活性的决定因素，同时利用药物发现平台开发小型 分子抑制剂针对这一药物靶点（目标2）。