Targeting aberrant enhancer landscapes in pancreatic cancer

项目摘要/摘要 该项目的中心目标是开发策略，对胰腺癌细胞进行表观遗传重新编程，以 减少转移扩散。这一目标是基于我们最近的研究表明，胰腺癌 转移伴随着一种典型的增强子激活模式。我们把开拓者牵连了进来 转录因子FOXA1作为增强子重新编程和转移扩散的驱动因素。在……里面 这一提议，我们试图定义增强子-转移的联系。在这样做的过程中，我们寻求提名一个新的 一类表观遗传靶点，可能是唯一能够消除转移潜能的靶点。第一个目标是 在这项提议中，我们将使用功能基因组学方法来干扰每个FOXA1调节的基因和 并确定是否可以抑制FOXA1依赖的转移。这种方法将需要 利用我们最近在以领域为重点的CRISPR筛查方面的创新，并将加深我们对 这一表观遗传计划中的促转移成分。在这项提议的第二个目标中，我们将 研究在FOXA1上调之前发生的增强子重新编程过程的最早步骤。 这一努力建立在我们意想不到的观察基础上，即肿瘤转移特异性增强子已经存在于 转移前胰腺肿瘤细胞的可及染色质状态。这表明额外的分子 事件发生在FOXA1上调之前，为转移过程中增强子重新编程奠定了基础。我们 将研究转录因子FOXA2，我们的实验表明它是关键的书签 在转移前癌细胞中打开转移特异性增强剂。此外，我们将确定如何 抑制性多梳复合体在FOXA1上调之前作用于抑制增强子激活。通过评估 FOXA2/Polycomb扰动的后果，我们将提供一个概念证明-转移- 相关的增强剂可以在胰腺癌进展的早期阶段消失。这样做的最终目的是 建议将我们的增强子图谱研究扩展到胰腺癌的鳞状亚型， 这是一种最近定义的疾病实体，与特别令人沮丧的预后有关。我们将聘请一名 新鉴定的胰腺癌患者来源的有机体补体以比较增强子图谱 鳞状细胞亚型与更典型的这种疾病的类型。我们将确定这一点的主要监管者 鳞状细胞转录程序，并进行遗传学实验以确定这些因素在 促进肿瘤进展和转移扩散。我们还将确定鳞状细胞在 PDA与独特的表观遗传依赖性有关。总的来说，拟议的研究将提供一个 以独特的增强子配置为靶点的表观遗传疗法的机制框架 转移性胰腺癌细胞。

Project Summary/Abstract The central goal of this project is to develop strategies to epigenetically reprogram pancreatic cancer cells to diminish metastatic spread. This objective is based on our recent demonstration that pancreatic cancer metastasis is accompanied by a stereotypical pattern of enhancer activation. We implicated the pioneer transcription factor FOXA1 as a driver of enhancer reprogramming and of metastatic spread in this context. In this proposal, we seek to define the enhancer-metastasis connection. In doing so, we seek to nominate a new class of epigenetic targets, which might be uniquely capable of eliminating metastatic potential. In the first Aim of this proposal, we will employ a functional genomics approach to perturb every FOXA1-regulated gene and enhancer and determine whether FOXA1-dependent metastasis can be suppressed. This approach will take advantage of our recent innovations in domain-focused CRISPR screening and will deepen our understanding of the pro-metastatic components of this epigenetic program. In the second Aim of this proposal, we will investigate the earliest steps of the enhancer reprogramming process that occur prior to FOXA1 upregulation. This effort builds from our unexpected observation that metastasis-specific enhancers are already present in an accessible chromatin state in pre-metastatic pancreatic tumor cells. This suggests that additional molecular events occur prior to FOXA1 upregulation to set the stage for enhancer reprogramming during metastasis. We will investigate the transcription factor FOXA2, which our experiments suggest is the critical bookmark that opens up metastasis-specific enhancers in pre-metastatic cancer cells. In addition, we will determine how repressive Polycomb complexes act to restrain enhancer activation prior to FOXA1 upregulation. By evaluating the consequences of FOXA2/Polycomb perturbation, we will provide a proof-of-concept that metastasis- associated enhancers can be effaced at early stages of pancreatic cancer progression. The final Aim of this proposal will be to extend our enhancer mapping studies into the squamous-subtype of pancreatic cancer, which is a recently defined disease entity associated with a particularly dismal prognosis. We will employ a newly characterized complement of patient-derived pancreatic cancer organoids to compare enhancer profiles of squamous-subtype versus the more classical form of this disease. We will identify master-regulators of this squamous transcriptional program, and perform genetic experiments to determine the role of such factors in promoting tumor progression and metastatic spread. We will also determine whether squamous cell identity in PDA is associated with unique epigenetic dependencies. Collectively, the proposed research will provide a mechanistic framework for developing epigenetic therapies that target the unique enhancer configuration of metastatic pancreatic cancer cells.