Defining epigenetic mechanisms in NPM1c mutant leukemia

项目摘要/摘要 核磷蛋白(NPM1)突变是急性髓系白血病(AML)最常见的突变之一 并导致包括HoxA/B簇上调在内的特征性干细胞样基因表达模式 基因及其辅助因子MEIS 1。NPM1c突变如何调节这种异常的分子机制 基因表达程序仍然知之甚少，目前还没有靶向治疗选择 可用。我们最近发现NPM1c突变型白血病依赖于组蛋白甲基转移酶MLL 及其适配蛋白Menin维持白血病基因表达和增殖。两国之间的相互作用 Menin和MLL对于MLL复合体向其靶基因亚群的招募是必不可少的，例如 Meis1，它们反过来对维持白血病的自我更新是必不可少的。美宁的治疗靶向- MLL与小分子抑制剂相互作用导致NPM1c自我更新和分化丧失 白血病细胞。NPM1c突变和MLL-复合体之间的联系仍有待解决。在 建议的项目，我们将发展一个全面的了解染色质状态发生在 NPM1c的存在，特别关注Menin和MLL在这一过程中的作用。为了实现这一目标，我们将 首先确定NPM1c降解时染色质状态的变化，并确定必要的蛋白质 NPM1c的结构域(目标1)。接下来，我们将确定哪些转录激活因子和染色质修饰因子 与NPM1c突变型白血病中导致靶基因异常的Menin-MLL复合体相关 激活(目标2)。最后，我们将集中讨论染色质结合因子LEDGF，它已被证明 结合Menin-MLL和招募转录激活因子来控制基因表达。我们的初步数据 提示在NPM1c突变的白血病细胞中LEDGF是一种依赖关系，并且LEDGF的缺失增强了 抑制脑膜素对细胞存活和MLL靶基因表达的不利影响(目标3)。总而言之， 从拟议的项目中获得的见解将有助于促进我们对NPM1c驱动的机械性理解 白血病的发展，目标是改善未来的治疗策略。

Project Summary/Abstract Nucleophosmin (NPM1) mutations are among the most common aberrations in acute myeloid leukemia (AML) and cause a characteristic stem cell-like gene expression pattern including the upregulation of HOXA/B cluster genes and their co-factors MEIS1. The molecular mechanisms of how NPM1c mutations regulate this aberrant gene expression program remains poorly understood and there are currently no targeted therapy options available. We have recently found that NPM1c mutant leukemias depend on the histone methyltransferase MLL and its adaptor protein Menin to maintain leukemia gene expression and proliferation. The interaction between Menin and MLL is essential for the recruitment of the MLL complex to a subgroup of its target genes, such as MEIS1, which are in turn essential for maintaining leukemic self-renewal. Therapeutic targeting of the Menin- MLL interaction with small molecule inhibitors causes a loss of self-renewal and differentiation of NPM1c leukemia cells. The link between NPM1c mutations and the MLL-complex remains to be resolved. In the proposed project, we will develop a comprehensive understanding of the chromatin state that occurs in the presence of NPM1c specifically focusing on the role of Menin and MLL in this process. To achieve this, we will first determine the changes in chromatin state upon NPM1c degradation and determine essential protein domains of NPM1c (Aim 1). Next, we will identify which transcriptional activators and chromatin modifiers associate with the Menin-MLL complex in NPM1c mutant leukemias that lead to the aberrant target gene activation (Aim 2). Finally, we will focus on the chromatin binding factor LEDGF, which has been shown to associate with Menin-MLL and recruit transcriptional activators to control gene expression. Our preliminary data suggests that LEDGF is a dependency in NPM1c mutant leukemia cells and that LEDGF loss enhances the detrimental effects of Menin-inhibition on cell survival and MLL-target gene expression (Aim 3). In summary, the insights gained from the proposed project will help advance our mechanistic understanding of NPM1c driven leukemia development with the goal of improving treatment strategies in the future.