The Role of CBFb-MYH11 in Acute Myeloid Leukemia

描述（由申请人提供）：影响核心结合因子（CBF）基因的易位是人类急性髓性白血病（AML）中最常见的遗传畸变之一，占所有AML的25%。其中近一半与16号染色体易位有关，导致融合蛋白CBF（- MYH11）的表达。本研究的总体目标是明确受CBF（-MYH11）影响的信号通路和下游靶基因，评估这些受调控基因在白血病干细胞自我更新、存活和分化中的作用，并确定与CBFP-MYH11协同参与白血病发生的信号通路。为了实现这一目标，我们建议在人类CD34+细胞中使用我们开发的融合基因表达模型，研究CBF（- MYH11）在获得导致白血病的合作突变之前的前白血病。我们已经成功地使用这个系统来模拟相关的白血病融合蛋白AML1-ETO。本提案的具体目的如下：目的1：定义CBF（-MYH 11）下游的信号通路。人CD34+细胞中CBF（-MYH11）的表达导致其在体外持续生长超过5个月。这些细胞将在增殖、存活和分化方面进行表征，并与相关CBF融合（AML1-ETO）引发的长期培养进行比较。目的2：鉴定cbfp - myh1靶基因并分析其在CBF（-MYH11）诱导的增殖中的作用。通过比较我们长期培养的CD34+细胞与正常CD34+细胞的转录组，将确定一个共同的基因表达谱。我们将通过过度表达那些被抑制的基因来分析这些被调节的目标基因的作用，反过来，通过敲低那些被上调的基因来分析这些被调节的目标基因的作用。目的3：确定在白血病发生中与CBF（-MYHl1）合作的信号通路。表达CBF（-MYH11）的白血病前培养物将作为检测合作突变的背景。为了确定具体的信号，将合作转化为急性白血病，确定的遗传因素和饱和逆转录病毒诱变将被使用。

DESCRIPTION (provided by applicant): Translocations affecting a core binding factor (CBF) gene are one of the most frequent genetic aberrations in human acute myeloid leukemia (AML), accounting for up to 25% of all AMLs. Nearly half of these are associated with translocations affecting chromosome 16, resulting in expression of the fusion protein CBF(- MYH11. The overall objective of the proposed studies is to define the signaling pathways and downstream target genes that are affected by CBF(-MYH11, to evaluate the role of these regulated genes in leukemic stem cell self-renewal, survival and differentiation, and to identify the signaling pathways that cooperate with CBFP-MYH11 in leukemogenesis. To accomplish this goal, we propose to use the model of fusion gene expression in human CD34+ cells we have developed, to study the pre-leukemia that is a result of CBF(- MYH11 expression prior to the acquisition of cooperating mutations that lead to frank leukemia. We have successfully used this system to model the related leukemia fusion protein AML1-ETO. The specific aims of this proposal are as follows: Aim 1: Define the signaling pathways downstream of CBF(-MYH 11. Expression of CBF(-MYH11 in human CD34+ cells leads to their continued growth in vitro for an extended period of greater than five months. These cells will be characterized in terms of their proliferation, survival and differentiation, and compared to the long-term cultures initiated by the related CBF fusion, AML1-ETO. Aim 2: Identify target genes of CBFp-MYHl1 and analyze their role in CBF(-MYH11 -induced proliferation. A common gene expression profile will be identified by comparing the transcriptome of CD34+ cells from our long-term cultures with normal CD34+ cells. We will analyze the contribution of these regulated target genes by over-expressing those that are repressed, and conversely by knocking-down those genes that become upregulated. Aim 3: Identify the signaling pathways that cooperate with CBF(-MYHl1 in leukemogenesis. The pre-leukemic cultures expressing CBF(-MYH11 will serve as the background in which cooperating mutations will be tested. To identify specific signals that will cooperate in the transformation to acute leukemia, defined genetic elements and saturating retroviral mutagenesis will be used.