Identifying the Drivers and Targeting Chemo Resistance in Ovarian Cancer

项目总结/摘要 卵巢癌是最致命的妇科恶性肿瘤。虽然大多数癌症病例是 最初对铂类化疗敏感，大多数患者最终会复发， 死于耐药性疾病我们缺乏对导致 耐药状态构成了阻碍该领域治疗进展的关键障碍。长期 我们的研究目标是了解染色质和转录调控网络， 细胞适应新的环境或发育线索。本研究的总体目标是 实现我们长期目标的下一步是确定主要的监管网络， 让卵巢癌细胞在化疗中存活。这些知识将识别改进的和有效的 治疗选择。 为了实现这一目标，我们从体外培养的人胚胎干细胞的表观基因组定位和转录组分析开始， 系统中，我们采用了化疗，化疗耐药，和再敏感的同基因细胞。综合 启动子和增强子的表达谱（RNA-Seq）和表观基因组特征分析 元件（H3 K27 ac ChIP-Seq），鉴定了大量典型的增强子和“超级增强子”的子集。 增强子”，在抗性细胞中特异性激活。值得注意的是，药物破坏超级 通过小分子表观遗传抑制剂的增强剂赋予顺铂对先前耐药的 在体外抑制细胞并在抗性细胞的异种移植模型中抑制体内肿瘤生长。超级增强剂 倾向于调节给定细胞状态的主调节因子的表达（1，2）。居前 抗性特异性超级增强子（RSSE）的靶基因是多个转录因子， 其被CRISPR介导的敲除显著地使抗性细胞敏感， 化疗 这些初步的数据导致了一个中心假设，即在细胞中异常的转录程序， 化疗耐药细胞由一组基因驱动，这些基因的表达受远端增强子调控， 可以被定向。该建议将确定增强剂的治疗效果 靶向克服化疗耐药性（目的1），确定化疗诱导的体内动力学 异常增强子激活（Aim 2），并描绘驱动化疗耐药性的核心TF 过程（目标3）。其基本原理是识别和靶向化学耐药细胞状态的主要驱动因素 遗传学表观遗传学和遗传学结果将使我们更好地了解 化学抗性的生物学，并能够开发新的和创新的治疗方法， 也适用于其他癌症。

PROJECT SUMMARY/ABSTRACT Ovarian cancer is the most lethal gynecological malignancy. Although majority of the cancer cases are initially sensitive to platinum-based chemotherapy, most patients eventually develop recurrence and succumb to chemoresistant disease. Our lack of understanding of the key drivers that lead to the resistant state poses a critical roadblock that impedes therapeutic progress in the field. The long-term goal of our research is to understand the chromatin and transcriptional regulatory networks that allow cells to adapt to new environmental or developmental cues. The overall objective of this study, which is the next step toward attainment of our long-term goal, is to identify the major regulatory networks that allow ovarian cancer cells to survive chemotherapy. This knowledge will identify improved and effective therapeutics options. To achieve this, we started with epigenome mapping and transcriptome analysis of an in vitro system in which we employed chemonaïve, chemoresistant, and resensitized isogenic cells. Integrative analysis of expression profiles (RNA-Seq) and epigenomic features of promoter and enhancer elements (H3K27ac ChIP-Seq), identified large number of typical enhancers and a subset of “super enhancers” that are specifically activated in resistant cells. Notably, pharmacological disruption of super enhancers by a small molecule epigenetic inhibitor confers cisplatin sensitivity to previously resistant cells in vitro and inhibits in vivo tumor growth in a xenograft model of resistant cells. Super enhancers tend to regulate the expression of master regulators of a given cellular state (1, 2). Among the top target genes of the resistant specific super enhancers (RSSE) were multiple transcription factors, whose depletion with CRISPR mediated knock significantly sensitized the resistant cells to chemotherapy. These preliminary data led to the central hypothesis that aberrant transcriptional program in chemoresistant cells is driven by a set of genes whose expression is regulated by distal enhancers that can be pharmacologically targeted. This proposal will determine the therapeutic efficacy of enhancer targeting to overcome chemoresistance (Aim 1), identify the in vivo dynamics of chemotherapy-induced aberrant enhancer activation (Aim 2), and delineate the core TFs that drives the chemoresistance process (Aim 3). The rationale is to identify and target the major drivers of chemoresistant cellular state genetically, epigenetically, and pharmacologically. The results will allow us to better understand the biology of chemoresistance, and enable development of new and innovative treatment approaches that are applicable to other cancers.