Functional dissection of oncogenic enhancers

 描述(申请人提供)：功能解剖致癌增强剂T细胞急性淋巴细胞白血病(T-ALL)占儿童T-ALL病例的10%至15%，占成人T-ALL病例的25%，最初被认为是与预后不良有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，但复发和难治性T-ALL患者的预后仍然非常差，这突显了确定导致疾病进展的分子机制和开发更有效的抗白血病药物的必要性。我们最近发现了N-Me，一个NOTCH1结合的增强子，驱动T细胞中MYC的表达。这种增强子在T-ALL中被反复扩增，并且是严格要求的 NOTCH1诱导转化。这些结果证明了长程调控序列在NOTCH1诱导的T-ALL发病机制中的关键作用，并突出了增强子驱动的基因表达机制作为人类癌症治疗靶点的潜力。根据我们的结果，我们假设N-me通过与其他尚未确定的长程调控序列相互作用，并通过T细胞系特异性转录因子的活性来调节T-ALL中的基因表达。此外，我们认为，致癌的NOTCH1除了控制MYC外，还控制着控制白血病致癌计划的主要调控因子的额外关键远程增强子，并且远程调控增强子在实体瘤的发病机制中发挥关键作用。这项建议的目的是促进我们对人类癌症远程转录调控的基本机制的理解，作为最终为这种疾病的治疗提供新的工具和靶点的第一步。为此，我们建议：(I)分析N-Me介导的Myc在T-ALL中表达的机制(目标1)；(Ii)使用CRISPR/Cas9基因组编辑工具从功能上剖析N-Me在体内控制Myc表达的作用(目标2)；(Iii)在实体瘤中鉴定NOTCH1结合的增强子(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).