CAK-RARa Signaling in HSC and Leukemic Cell Commitment to Differentiation

HSC 和白血病细胞分化中的 CAK-RARa 信号转导

• 批准号: 7372340
• 负责人: LINGTAO WU
• 金额: $ 32.68万
• 依托单位: CHILDREN'S HOSPITAL OF LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7372340
• 关键词: Aldehyde dehydrogenase (NAD+); Binding; Biological Assay; Cell Cycle; Cell Differentiation process; Cell division; Cell model; Cells; Chromatin; Commit; Couples; Data; Development; Differentiation Therapy; Disruption; Dissociation; Environment; Equilibrium; Gene Expression; Gene Targeting; Goals; Granulopoiesis; Hematopoietic; Hematopoietic stem cells; Human; In Vitro; Leukemic Cell; Ligands; Mediating; Molecular; Myelogenous; Myeloid Cells; Myeloid Leukemia; Phosphorylation; Plant Roots; Post-Translational Regulation; Process; Proteolysis; Publishing; Regulation; Reporter Genes; Research; Role; SCID Mice; Signal Transduction; Staging; Structure-Activity Relationship; Testing; Time; Transactivation; Transcriptional Regulation; Tretinoin; Ubiquitination; aldehyde dehydrogenases; base; cellular transduction; chromatin immunoprecipitation; cyclin-dependent kinase-activating kinase; design; granulocyte; insight; leukemogenesis; monocyte; mutant; novel; prevent; progenitor; research study; retinoic acid receptor alpha; self-renewal; small hairpin RNA; spatiotemporal; transcription factor

DESCRIPTION (provided by applicant): Aberrant differentiation is a hallmark of myeloid leukemia, reflecting a disruption of the intrinsic balance between proliferation and differentiation. Our published and preliminary data indicate that subverted RAR?-CAK signaling is a pivotal feature of myeloid leukemogenesis and challenges the current paradigm that RA induces cell differentiation solely by transactivating target genes. We propose to determine how RAR?-CAK signaling couples CAK-dependent G1 exit to transcriptional control of granulocytic differentiation in normal and leukemic myeloid cells. The long-term goal of our research is to provide fundamental basis for development of differentiation therapy that can force the terminal differentiation of myeloid leukemia cells. Normal cellular differentiation requires timely exit from the cell cycle. CAK, whose activity is determined by its targeting subunit MAT1, regulates cell cycle G1 exit when cells commonly commit to proliferation or to differentiation. The mechanisms by which transcription factor RAR? mediates the effect of RA to coordinate the granulocytic proliferation/differentiation (P/D) transition during granulopoiesis are unknown. We discovered that, in myeloid leukemic cells, the lack of RA-induced ubiquitination-proteolysis of MAT1 inhibits CAK-dependent G1 exit and sustains CAK hyperphosphorylation of RAR1 to prevent granulocytic differentiation. This contrasts with the P/D transition in normal hematopoietic cells, where intrinsic MAT1 degradation proceeds together with progressive granulocytic differentiation, and the loss of RAR? phosphorylation by CAK induces RA-target gene expression and granulocytic differentiation. Using in vitro cellular models and NOD/SCID mice, the proposed experiments seek to: a) evaluate the role and mechanism of MAT1 expression and degradation in normal granulopoiesis; b) evaluate the mechanisms of RA-induced ubiquitination-proteolysis of MAT1, c) determine the role and mechanism of RAR? hypophosphorylation in transcriptional control of granulocytic differentiation; and d) define the role of ALDH1A1 and 1B1 in initiating RAR?-CAK signaling during granulopoiesis. The proposed specific aims will examine, for the first time, the novel mechanisms by which CAK-RAR? signaling coordinates CAK-dependent post-translational regulation of G1 exit to RAR?-dependent transcriptional control of granulocytic differentiation. This project has the potential to generate valuable insights into the molecular regulation of granulopoiesis and therefore has clear relevance to the design of effective differentiation therapies against myeloid leukemia.

描述（由申请人提供）：异常分化是髓性白血病的标志，反映了增殖和分化之间内在平衡的破坏。我们发表的初步数据表明，颠覆RAR？- CAK信号是髓系白血病发生的关键特征，并挑战了目前RA仅通过反式激活靶基因诱导细胞分化的范式。我们建议确定如何RAR？- CAK信号传导将CAK依赖的G1出口与正常和白血病骨髓细胞中粒细胞分化的转录控制偶联。本研究的长期目标是为开发能促使髓系白血病细胞终末分化的分化治疗方法提供基础。正常的细胞分化需要及时退出细胞周期。CAK的活性由其靶向亚基MAT 1决定，当细胞通常致力于增殖或分化时，CAK调节细胞周期G1退出。转录因子RAR？调节RA在粒细胞生成过程中协调粒细胞增殖/分化（P/D）转变的作用尚不清楚。我们发现，在髓系白血病细胞中，RA诱导的MAT 1泛素化-蛋白水解的缺乏抑制CAK依赖的G1退出，并维持RAR 1的CAK过度磷酸化，以防止粒细胞分化。这与正常造血细胞中的P/D转换形成对比，在正常造血细胞中，固有的MAT 1降解与进行性粒细胞分化一起进行，并且RAR？通过CAK的磷酸化诱导RA靶基因表达和粒细胞分化。本实验采用体外细胞模型和NOD/SCID小鼠，旨在：a）评价MAT 1在正常粒系造血中的表达和降解的作用和机制; B）评价RA诱导的MAT 1泛素化-蛋白水解的机制; c）确定RAR？在粒细胞分化的转录控制中的低磷酸化;和d）确定ALDH 1A 1和1B 1在启动RAR？粒细胞生成过程中的CAK信号传导。拟议的具体目标将审查，第一次，新的机制，CAK-RAR？信号传导协调CAK依赖的G1出口到RAR？的翻译后调节。粒细胞分化的依赖性转录控制。该项目有可能产生有价值的见解，粒细胞生成的分子调控，因此有明确的相关性，有效的分化治疗对髓性白血病的设计。