Functional dissection of oncogenic enhancers

 描述（由申请人提供）：致癌增强子的功能性解剖T细胞急性淋巴细胞白血病（T-ALL）占儿童T-ALL病例的10%-15%和成人T-ALL病例的25%，最初被确定为与预后不良相关的高度侵袭性肿瘤。尽管最近在治疗这种疾病方面取得了进展，但复发性和难治性T-ALL患者的预后仍然极差，这强调了需要确定导致疾病进展的分子机制并开发更有效的抗白血病药物。我们最近发现了N-Me，一种在T细胞中驱动MYC表达的NOTCH 1结合增强子。该增强子在T-ALL中反复扩增，并且是T-ALL的严格要求。 NOTCH 1诱导的转化。这些结果表明，在NOTCH 1诱导的T-ALL的发病机制中的长程调控序列的关键作用，并强调了增强子驱动的基因表达机制作为治疗人类癌症的治疗靶点的潜力。基于我们的结果，我们假设N-Me通过与其他尚未表征的长程调控序列相互作用以及通过T细胞谱系特异性转录因子的活性来调节T-ALL中的基因表达。此外，我们提出，致癌NOTCH 1控制额外的关键远程增强子控制主调节白血病致癌程序除了MYC和远程调节增强子在实体瘤的发病机制中发挥关键作用。该提案的目标是促进我们对人类癌症中远程转录调控的基本机制的理解，作为最终为治疗这种疾病提供新工具和靶点的第一步。为此，我们提出：（i）分析T-ALL中N-Me介导的Myc表达的机制（目标1）;（ii）使用CRISPR/Cas9基因组编辑工具功能性剖析N-Me在体内控制Myc表达中的作用（目标2）;以及（iii）鉴定实体瘤中的NOTCH 1结合增强子（目标3）。

 DESCRIPTION (provided by applicant): Functional dissection of oncogenic enhancers T cell acute lymphoblastic leukemia (T-ALL) accounts for 10% to 15% of pediatric and 25% of adult T-ALL cases and was originally identified as highly aggressive tumor associated to poor prognosis. Despite recent progress in the treatment of this disease, the prognosis of patients with relapsed and refractory T-ALL remain extremely poor, underscoring the need to identify molecular mechanisms responsible for disease progression and to develop more effective antileukemic drugs. We recently identified N-Me, a NOTCH1-bound enhancer driving MYC expression in T-cells. This enhancer is recurrently amplified in T-ALL and is strictly required for NOTCH1-induced transformation. These results demonstrate a critical role for long-range regulatory sequences in the pathogenesis of NOTCH1-induced T-ALL and highlight the potential for enhancer-driven gene expression mechanisms as a therapeutic target for the treatment of human cancer. Based on our results, we hypothesize that N-Me regulates gene expression in T- ALL by interacting with additional as yet uncharacterized long-range regulatory sequences and via the activity of T-cell lineage specific transcription factors. Moreover, we propose that oncogenic NOTCH1 controls additional key long range enhancers controlling master regulators of the leukemia oncogenic program in addition to MYC and that long range regulatory enhancers play a critical role in the pathogenesis solid tumors. The goal of this proposal is to advance our understanding of the basic mechanisms of long-range transcriptional regulation in human cancer as a first step to ultimately provide new tools and targets for the treatment of this disease. Toward this objective we propose: (i) To analyze the mechanisms of N-Me mediated Myc expression in T-ALL (Aim 1); (ii) To functionally dissect the role of N-Me in the control of Myc expression in vivo using CRISPR/Cas9 genome editing tools (Aim 2); and (iii) To identify NOTCH1-bound enhancers in solid tumors (Aim 3).