Transcriptional regulation of leukemic stem cells in acute myeloid leukemia

描述（由申请人提供）：急性髓性白血病（AMI）是一种恶性疾病，起源于单个转化细胞，该细胞已逐渐获得破坏关键生长调节途径的关键遗传变化。尽管已确立使用和优化应用多种化疗的方案，并开发了多种有效降低白血病患者肿瘤负荷的新药，但复发仍然是AML最常见的死亡原因。较新的实验证据表明，AML来自一小群白血病干细胞（LSC）。与正常造血干细胞（HSC）相似，LSC在细胞周期方面是静止的，因此，在大多数情况下，常规细胞毒性疗法对LSC无效。然而，治疗性根除白血病克隆内的LSC对于治愈疾病是必不可少的。因此，需要更好地了解抑制LSC形成和维持的分子途径，以开发靶向LSC而不是大量肿瘤细胞（白血病母细胞）的疗法。最近的研究结果表明，包括PU的转录因子的关键作用。1和JUNB在小鼠和人类AML中LSC的发生和功能中的作用，并且PU.1和JUNB在早期干细胞区室中已经失调。因此，本研究项目的目标是1）阐明PU.1和JUNB在AML-LSC中的确切作用机制，2）鉴定干细胞中对LSC功能重要的PU.1的新靶基因，和3）确定干细胞区室中的其他功能关键性改变，这些改变是遗传定义的AML亚型中LSC形成和维持的基础，转录因子功能为了鉴定涉及的途径，将通过多参数高速荧光激活细胞分选分离严格定义的干细胞和祖细胞亚群，然后进行线性RNA扩增和转录分析。将利用系列再铺板试验以及鼠移植模型对鉴定的靶标进行功能性检测，以评估其在LSC中的功能。这些研究将为开发可能最终治愈AML的LSC导向疗法提供基础。

DESCRIPTION (provided by applicant): Acute myeloid leukemia (AMI) is a malignant disease that originates from a single transformed cell which has progressively acquired critical genetic changes that disrupt key growth-regulatory pathways. Despite the established use and optimization of regimens applying polychemotherapy and the development of multiple new agents that are effective at reducing the tumor burden in patients with leukemia, relapse continues to be the most common cause of death in AML. Newer experimental evidence demonstrates that AML arises from a small population of leukemic stem cells (LSC). Similar to normal hematopoietic stem cells (HSC), LSC are quiescent in terms of cell cycle and thus, conventional cytotoxic therapies are not effective against LSC in the majority of cases. However, therapeutic eradication of the LSC within the leukemia clone will be essential for a cure of disease. Therefore, an improved understanding of the molecular pathways that suppress the formation and maintenance of LSC is required for the development of therapies that target LSC rather than the bulk tumor cells (leukemic blasts). Recent findings demonstrate a critical role of transcription factors including PU. 1 and JUNB in the genesis and function of LSC in AML in mice and humans, and that PU.1 and JUNB are already deregulated in the early stem cell compartment. Therefore, the goals of this research project are 1) to clarify the exact mechanism of action of PU.1 and JUNB in AML-LSC, 2) to identify new target genes of PU.1 in stem cells that are important for LSC function, and 3) to identify other functionally critical alterations in the stem cell compartment that underlie the formation and maintenance of LSC in genetically defined subtypes of AML with disruption of transcription factor function. To identify implicated pathways rigorously defined stem and progenitor cell subsets will be isolated by means of multi-parameter high-speed fluorescence-activated cell sorting and then subjected to linear RNA amplification and transcriptional analysis. Identified targets will be functionally tested utilizing serial replating assays as well as murine transplantation models to assess their function in LSC. These studies will provide the basis for the development of LSC-directed therapies that might ultimately lead to a cure of AML.