Understanding Resistance to Next Generation Antiandrogens

项目摘要/摘要 该R01竞争性更新应用侧重于获得性激素抵抗的新机制 耐去势前列腺癌(CRPC)的治疗称为谱系可塑性。在最初的5年内 在资金周期中，我们主要关注另外两种耐药机制：突变或扩增 雄激素受体(AR)及其通过上调相关糖皮质激素对AR信号的旁路 受体。这项工作在研究战略的进度报告部分和 《进度报告》发表名单中引用的论文。在这里，我们将注意力转移到第三种机制 我们最近报道的获得性抵抗称为谱系可塑性，在这种情况下前列腺癌逃脱 通过将他们的身份从AR依赖的管腔血统表型改变为AR来进行激素治疗 独立的非流明血统。这种耐药机制主要发生在缺乏肿瘤的肿瘤中。 抑制基因TP53和RB1(约占CRPC的15%)，部分可以通过上调来解释 重编程因子SOX2，使腔上皮细胞获得基本的 上皮细胞、间充质细胞和神经内分泌细胞不再依赖AR信号生存。 我们已经开发了基因定义的小鼠和人类前列腺癌模型(使用有机化合物 技术、异种移植和原位肿瘤模型)，概括了世系可塑性的所有表型 在CRPC患者中观察到了可重复的、明确的动力学，使这些模型适用于详细的 机械调查。在目标1中，我们将确定这些世系转变的调节者，从一个 使用rna-seq、atac-seq、染色质芯片-seq和单细胞rna-seq进行的一系列时间序列实验 定义与这些表型变化相关的转录和染色质景观变化。目标 2将阐述抗雄激素治疗加速谱系发育的机制。 可塑性，我们认为这是通过破坏AR驱动的转录程序来帮助维持 流明身份。这一结果可能会对激素治疗的时机和背景产生影响 用于临床。在目标3中，我们将确定阻止谱系可塑性发展的候选药物靶点。 通过对专门关注染色质修饰酶的文库进行集合CRISPR筛选 (根据我们最近的数据选择，EZH2就是这样一个目标)。我们将描述来自 这项筛查的长期目标是开发联合治疗方案(含抗雄激素治疗) 以防止抵抗。总而言之，这个应用程序将产生对血统的新的机械论见解 前列腺癌的可塑性，对耐药的临床挑战具有明显的意义。调查结果 也可能与其他上皮性肿瘤类型相关，如肺癌、乳腺癌和 黑色素瘤的证据表明，谱系可塑性是耐药的一个原因也已经出现。

PROJECT SUMMARY/ABSTRACT This R01 competitive renewal application focuses on a novel mechanism of acquired resistance to hormone therapy in castration resistant prostate cancer (CRPC) called lineage plasticity. During the initial 5 year funding cycle, we focused primarily on two other mechanisms of resistance: mutation or amplification of the androgen receptor (AR) and bypass of AR signaling through upregulation of the closely related glucocorticoid receptor. This work is described briefly in the Progress Report section of the Research Strategy and in the papers cited in the Progress Report Publication List. Here we shift our attention to a third mechanism of acquired resistance that we recently reported called lineage plasticity, in which prostate cancers escape hormone therapy by changing their identity from an AR dependent luminal lineage phenotype to an AR independent non-luminal lineage. This resistance mechanism occurs primarily in tumors deficient in the tumor suppressor genes TP53 and RB1 (which account for ~15% of CRPC) and is explained, in part, by upregulation of the reprogramming factor SOX2 which enables luminal epithelial cells to acquire characteristics of basal epithelial, mesenchymal and neuroendocrine cells that are no longer dependent on AR signaling for survival. We have developed genetically-defined mouse and human prostate cancer models (using organoid technology, xenografts and orthotopic tumor models) that recapitulate all the phenotypes of lineage plasticity observed in CRPC patients with reproducible, defined kinetics that make these models suitable for detailed mechanistic investigation. In Aim 1, we will identify the regulators of these lineage transitions, starting with a series of timecourse experiments using RNA-seq, ATAC-seq, chromatin ChIP-seq and single cell RNA-seq to define the transcriptomic and chromatin landscape changes associated with these changing phenotypes. Aim 2 will address the mechanism by which antiandrogen therapy can accelerate the development of lineage plasticity, which we postulate is through disruption of an AR-driven transcriptional program that helps maintain luminal identity. The results could have implications for the timing and context in which hormone therapy is used clinically. In Aim 3, we will identify candidate drug targets that block the development of lineage plasticity by conducting a pooled CRISPR screen of a library focused exclusively on chromatin modifying enzymes (selected based on our recent data implicating EZH2 as one such target). We will characterize the hits from this screen with the long range goal of developing combination therapy regimens (with antiandrogen therapy) that prevent resistance. In summary, this application will generate novel mechanistic insight into lineage plasticity in prostate cancer, with obvious implications for the clinical challenge of drug resistance. The findings are also likely to have relevance for other epithelial tumor types such as lung cancer, breast cancer and melanoma where evidence implicating lineage plasticity as a cause of drug resistance has also emerged.