Transcriptional regulation of leukemic stem cells in acute myeloid leukemia

描述(申请人提供)：急性髓系白血病(AMI)是一种恶性疾病，起源于单个转化的细胞，该细胞逐渐获得关键的基因变化，扰乱关键的生长调节途径。尽管多种化疗方案的使用和优化已经确立，多种新药物的开发也有效地减轻了白血病患者的肿瘤负担，但复发仍然是急性髓细胞白血病最常见的死亡原因。较新的实验证据表明，AML起源于一小部分白血病干细胞(LSC)。与正常的造血干细胞(HSC)相似，LSC在细胞周期方面是静止的，因此，在大多数病例中，传统的细胞毒疗法对LSC无效。然而，白血病克隆体内的LSC的治疗性根除将是治愈疾病的关键。因此，需要更好地了解抑制LSC形成和维持的分子途径，以开发针对LSC而不是大块肿瘤细胞(白血病母细胞)的治疗方法。最近的发现证明了包括PU在内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在早期干细胞室中已经被解除调控。因此，本研究的目标是1)阐明PU.1和JunB在AML-LSC中的确切作用机制，2)在干细胞中发现对LSC功能重要的PU.1新的靶基因，3)在转录因子功能中断的AML基因亚型中，确定干细胞室的其他关键功能变化，这些变化是导致LSC形成和维持的基础。为了确定相关的通路，严格定义的干细胞和祖细胞亚群将通过多参数高速荧光激活细胞分选方法分离出来，然后进行线性RNA扩增和转录分析。识别的靶点将利用系列重复分析和小鼠移植模型进行功能测试，以评估它们在LSC中的功能。这些研究将为LSC导向疗法的发展提供基础，最终可能导致AML的治愈。

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.