Notch 1 Regulation of T-ALL Genomes

癌症研究领域的一个重大差距是缺乏公正的、全基因组的研究来描述 激活的Notch如何调节癌细胞的基因组。我们建议通过以下方式开始填补这一空白 激活的Notchl(ICNI)如何与T-ALL细胞基因组相互作用支持白血病细胞 成长。我们将通过追求以下两个特定的方法来解决T-ALL发病机制中的这个中心问题 目标： 目的1.确定Notchl如何反式激活靶基因 当前的靶基因Notch调节模型仅基于对几个基因的分析(例如， I-ies1)在不同的细胞环境中。我们的初步数据表明，个别Notchl结合位点显示 对γ-分泌酶抑制剂(GSLS)的差异敏感性，这一特征可能定义动态NRES和 这指向了一个意想不到的GSI难治性染色质相关Notchl池。在这个目标中，我们将首先 使用ChlP-Seq在全基因组的基础上确定染色质相关Notchl的GSI敏感性。 然后，有了一整套强大的靶基因和GSI敏感的Notchl结合位点，我们将测试和 改良Notchl调控T-ALL细胞基因表达的模型。我们预期这些研究将会 阐明Notch调控靶基因的基本机制并揭示新的机遇 以Notch通路为靶点的治疗。 目的2.确定顺式调节辅助因子对Notchl靶基因表达的影响 在人和小鼠T-ALL细胞中进行的基序分析表明，Notchl基因组结合位点是 通常位于RUNX因子或ETS因子的基序两侧，或与Znf143的结合位点精确重叠。在……里面 初步数据，我们观察到RUNX因子和ETS因子似乎共同调节重要 Notchl以iL7R等有助于T-ALL细胞生长和存活的基因为靶点。我们将扩大规模 在这些数据的基础上，研究ETS和RUNX因子如何共同调节关键的靶基因，并将阐明 Notch1和znf143之间的关系普遍而复杂。 这两个目标中描述的工作将极大地促进我们对 T-ALL的分子发病机制，并由此为靶向Notch创造了新的机会 在癌症和其他与Notch信号失控相关的疾病中的信号转导途径。

A significant gap in the field of cancer research is the lack of unbiased, genome-wide studies describing how activated Notch regulates the genomes of cancer cells. We propose to begin to fill this gap by elucidating how activated Notchl (ICNI) interacts with the genomes of T-ALL cells to support leukemia cell growth. We will address this central issue in T-ALL pathogenesis by pursuing the following two specific aims: Aim 1. To determine how Notchl transactivates target genes Current models for Notch regulation of target genes have been based on analyses of only a few genes (e.g., i-ies1) in diverse cellular contexts. Our preliminary data suggest that individual Notchl binding sites show differential sensitivity to y-secretase inhibitors (GSls), a characteristic that may define dynamic NREs and which points to an unexpected pool of GSI-refractory chromatin-associated Notchl. In this aim, we will first use ChlP-Seq to determine the GSI-sensitivity of chromatin-associated Notchl on a genome-wide basis. Then, with a full set of robust target genes and GSI-sensitive Notchl binding sites in hand, we will test and refine models of Notchl regulation of gene expression in T-ALL cells. We anticipate that these studies will illuminate fundamental mechanisms of target gene regulation by Notch and reveal new opportunities for therapeutic targeting ofthe Notch pathway. Aim 2. To determine the contributions of cis-regulatory co-factors to Notchl target gene expression Motif analysis carried out in human and murine T-ALL cells showed that Notchl genomic binding sites are often flanked by motifs for Runx factors or Ets factors, or overlap precisely with binding sites for Znf143. In preliminary data, we have observed that Runx factors and Ets factors appear to co-regulate important Notchl target genes such as iL7R that contribute to the growth and survival of T-ALL cells. We will expand upon these data to study how Ets and Runx factors co-regulate key target genes, and will also elucidate the pervasive, but complex relationship of Notchl and Znf143. Together, the work described in these two aims will substantially advance our understanding of the molecular pathogenesis of T-ALL, and in doing so create new opportunities for targeting of the Notch pathway in cancer and in other forms of disease related to dysregulated Notch signaling.