Notch 1 Regulation of T-ALL Genomes

癌症研究领域的一个重大差距是缺乏无偏见的全基因组研究， 激活的Notch如何调节癌细胞的基因组。我们建议开始填补这一空白， 阐明活化的Notchl（ICNI）如何与T-ALL细胞的基因组相互作用以支持白血病细胞 增长我们将通过以下两个具体的研究来解决T-ALL发病机制中的这一核心问题： 目的： 目标1。为了确定Notchl如何反式激活靶基因 目前靶基因的Notch调控模型仅基于对少数基因的分析（例如， i-ies1）。我们的初步数据表明，单个Notchl结合位点显示， 对γ-分泌酶抑制剂（GSL）的敏感性差异，这是一个可以定义动态NRE的特征， 这表明了一个意想不到的GSI难治性染色质相关Notchl库。为此，我们将首先 使用ChIP-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 改进Notchl调节T-ALL细胞中基因表达的模型。我们预计，这些研究将 阐明Notch调控靶基因的基本机制，并揭示新的机会， Notch通路的治疗靶向。 目标2.确定顺式调节辅因子对Notchl靶基因表达的贡献 在人和鼠T-ALL细胞中进行的基序分析显示Notchl基因组结合位点是 通常侧接Runx因子或Ets因子的基序，或与Znf 143的结合位点精确重叠。在 初步数据，我们观察到Runx因子和Ets因子似乎共同调节重要的 Notchl靶向基因，如有助于T-ALL细胞生长和存活的iL7R。我们将扩大 基于这些数据，研究Ets和Runx因子如何共同调节关键靶基因，并将阐明Ets和Runx因子的相互作用。 Notchl和Znf143的普遍但复杂的关系。 这两个目标中所描述的工作将大大促进我们对 T-ALL的分子发病机制，并在这样做时为Notch的靶向创造了新的机会。 在癌症和其他形式的疾病中与Notch信号转导失调相关的信号通路。

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.