SATB1-dependent epigenetic regulation of leukemia initiating cells

白血病起始细胞的 SATB1 依赖性表观遗传调控

• 批准号: 8203213
• 负责人: Britta Will
• 金额: $ 5.13万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2011-09-02
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8203213
• 关键词: AT Rich Sequence; Acute Myelocytic Leukemia; Address; Adult; Affinity; Architecture; Binding; Binding Proteins; Binding Sites; Biological Assay; Cell physiology; Cells; Chromatin Remodeling Factor; Chromosome Mapping; Complex; DNA; DNA Methylation; DNA Sequence; Data; Defect; Development; Disease; Embryo; Ensure; Epigenetic Process; Erythroid Progenitor Cells; Gene Activation; Gene Expression; Gene Expression Profiling; Gene Expression Regulation; Gene Mutation; Gene Targeting; Genes; Genetic; Genetic Models; Globin; Goals; Hematopoiesis; Hematopoietic; Hematopoietic System; Hematopoietic stem cells; Individual; Karyotype; Maintenance; Malignant - descriptor; Malignant Neoplasms; Modeling; Molecular; Myelogenous; Nuclear; Outcomes Research; Pathway interactions; Patients; Pattern; Play; Process; Proteins; Regulation; Regulatory Element; Reporting; Research; Role; SPI1 gene; Shapes; Single Nucleotide Polymorphism; Stem cell transplant; Stem cells; Subgroup; T-Lymphocyte; Therapeutic; Therapeutic Intervention; Tissues; Transplantation; Tumor Suppressor Genes; Work; base; cell transformation; chromatin immunoprecipitation; chromatin remodeling; epigenomics; gene repression; in vivo; in vivo Model; insight; leukemia; leukemic stem cell; novel; outcome forecast; programs; restoration; self-renewal; stem; stem cell differentiation; therapeutic target; transcription factor

DESCRIPTION (provided by applicant): In the hematopoietic system, the interplay of particular transcription factors instructs normal hematopoietic stem cells (HSC) to function in a precise manner. While it is known that expression deregulation of specific factors in these transcriptional networks disrupts normal HSC function and leads to the formation of leukemia initiating cells (LIC), superordinate gene expression regulation by epigenetic mechanisms, is still poorly understood. We and others have identified a particular chromatin remodeling factor, special AT-rich sequence-binding protein 1 (SATB1) as an important epigenetic factor governing gene expression in normal T-cell and myeloid differentiation, and in leukemia. Our preliminary data show: SATB1 is required for self-renewal function of HSC, sequence alterations within the SATB1-binding site of an upstream regulatory element of the myeloid master regulator PU.1 act as disease modifiers in AML, and while SATB1 is highly expressed in normal hematopoietic stem and progenitor cells, its expression is impaired in AML patient-derived LIC. We hypothesize that this chromatin remodeling protein regulates the function of normal HSC and malignant stem cells. Since epigenetic alterations do not change the DNA sequences and are pharmacologically reversible, they have been regarded as promising targets for therapy. We propose to investigate epigenetic gene regulation by the chromatin-remodeling protein SATB1 in HSC and LIC. The function of SATB1-dependent gene expression regulation in HSC and LIC will be characterized using in vivo models, such as stem cell transplantation assays. Additionally, these functional studies will be accompanied with integrated epigenomic analyses investigating the mechanism of SATB1-dependent HSC and LIC regulation. We will utilize global chromatin immunoprecipitation analysis (ChIP-seq) in combination with gene expression and DNA methylation pattern analysis. Given our observation that SATB1 is down- regulated in LIC of AML patients, binding of SATB1 to low affinity binding sites may be abrogated and cause expression changes of genes involved in the formation or maintenance of LIC. We will restore SATB1 expression in AML patient-derived LIC and evaluate whether this has an anti-leukemic effect. We will characterize SATB1 binding patterns in AML LIC with low and restored SATB1 expression by ChIP-seq combined with gene expression profiling. Genes differentially occupied and expressed will be further functionally analyzed to determine their potential use as therapeutic targets. Our preliminary data make SATB1 a potential paradigm for epigenetic regulation of tumor suppressor genes in leukemia stem cells. Our study will contribute to elucidating novel molecular pathways that can be targeted for the development of LIC-directed epigenetic therapeutic approaches. PUBLIC HEALTH RELEVANCE: Project Narrative Our study will investigate the function of special AT-rich sequence-binding protein 1 (SATB1), a DNA- organizing ('epi-genetic') factor we have found in normal blood stem cells and cells that initiate acute myeloid leukemia (AML). Our preliminary data show that the presence of SATB1 is required to ensure normal blood stem cell function and our observations further suggest that SATB1 critically contributes not only to the function of normal blood stem cells, but also cells that initiate leukemia. The results of our study will add to our current understanding of normal blood cell production and will also identify fundamentally novel pathways and targets for specific, leukemia initiating cell-directed therapies.

描述（由申请人提供）：在造血系统中，特定转录因子的相互作用指导正常造血干细胞（HSC）以精确的方式发挥功能。虽然已知这些转录网络中特定因子的表达失调破坏了正常HSC功能并导致白血病起始细胞（LIC）的形成，但通过表观遗传机制的上位基因表达调控仍然知之甚少。 我们和其他人已经确定了一个特殊的染色质重塑因子，特殊的AT-丰富的序列结合蛋白1（SATB 1）作为一个重要的表观遗传因子，在正常的T细胞和髓样分化的基因表达，并在白血病。我们的初步数据显示：SATB 1是HSC自我更新功能所必需的，髓样主调节因子PU. 1的上游调节元件的SATB 1结合位点内的序列改变在AML中充当疾病调节剂，并且虽然SATB 1在正常造血干细胞和祖细胞中高度表达，但其表达在AML患者来源的LIC中受损。我们推测这种染色质重塑蛋白调节正常HSC和恶性干细胞的功能。由于表观遗传改变不改变DNA序列并且是可逆的，因此它们被认为是有希望的治疗靶点。我们建议研究HSC和LIC中染色质重塑蛋白SATB 1的表观遗传基因调控。 HSC和LIC中SATB 1依赖性基因表达调控的功能将使用体内模型如干细胞移植测定来表征。此外，这些功能研究将伴随着综合表观基因组分析，调查SATB 1依赖性HSC和LIC调控的机制。我们将利用全局染色质免疫沉淀分析（ChIP-seq）结合基因表达和DNA甲基化模式分析。鉴于我们观察到SATB 1在AML患者的LIC中下调，SATB 1与低亲和力结合位点的结合可能被消除并引起参与LIC形成或维持的基因的表达变化。我们将在AML患者来源的LIC中恢复SATB 1表达，并评估这是否具有抗白血病作用。我们将通过ChIP-seq结合基因表达谱分析来表征SATB 1低表达和恢复表达的AML LIC中的SATB 1结合模式。差异占据和表达的基因将进一步进行功能分析，以确定其作为治疗靶点的潜在用途。 我们的初步数据使SATB 1成为白血病干细胞中肿瘤抑制基因表观遗传调控的潜在范例。我们的研究将有助于阐明新的分子途径，可以有针对性的LIC指导的表观遗传治疗方法的发展。 公共卫生相关性：我们的研究将探讨特殊的富含AT的序列结合蛋白1（SATB 1）的功能，SATB 1是我们在正常造血干细胞和引发急性髓性白血病（AML）的细胞中发现的一种DNA组织（"表观遗传"）因子。我们的初步数据表明，SATB 1的存在是确保正常造血干细胞功能所必需的，我们的观察进一步表明，SATB 1不仅对正常造血干细胞的功能有重要作用，而且对引发白血病的细胞也有重要作用。我们的研究结果将增加我们目前对正常血细胞产生的理解，并将从根本上确定特定的白血病启动细胞导向疗法的新途径和靶点。