Studies on Lineage Plasticity in Prostate Cancer

项目总结 尽管靶向癌症治疗取得了显著的成功，但某些癌症，包括肺癌、乳腺癌和 前列腺癌和黑色素瘤总是对治疗产生抵抗力。一种继发性的机制 抗性--谱系可塑性--在细胞转变为侵袭性状态时发生，在前列腺的情况下 癌症，获得神经内分泌组织学。这导致了所谓的 耐去势前列腺癌(CRPC)患者。本质上，这不仅构成了临床上的挑战，而且 也让我们面临着一个悬而未决的生物学问题--血统的分子基础是什么 可塑性，更重要的是，这一过程能否逆转？我们最近记录到了这种激活 JAK/STAT和FGFR信号通路促进谱系可塑性并导致对 雄激素受体信号转导抑制物[*Chan，*Zaidi，et al，Science，2022年，PMID：35981096，*co- 第一作者]。重要的是，我们发现FDA批准的JAK/STAT(Ruxolitinib)和FGFR抑制剂 (Erdafitinib)协同逆转谱系可塑性并恢复ARSI敏感性。因此，我们假设 JAK/STAT和FGFR下游的信号，包括新的转录因子，相互作用促进谱系 塑性，它们的定时扰动可以逆转塑性和ARSI不敏感性。因此，在具体目标1中， 研究FGFR信号如何与JAK/STAT协同传递可塑性，我们将使用化学抑制剂和 CRISPR-Cas9用于删除TP53/RB1缺失的小鼠和人类肿瘤类器官中的特定分子。特定的 目标2将专注于通过无偏见的单一 小鼠器官中的细胞配对RNA和ATAC(多组体)测序。我们希望确定新的转录 在家族可塑性的进化过程中，研究TP53/RB1缺失后的因素及其DNA可获得性， 不含鲁索利替尼和/或厄达菲替尼。在具体目标3中，在活体概念验证研究中，我们将检查 鲁索利替尼联合厄达非替尼逆转谱系可塑性及修复的疗效观察 ARSI敏感度。为此，Ruxolitinib+erdafitinib的组合将在NOD SCID小鼠身上进行研究，无论是移植到哪一个 使用TP53/RB1缺失的小鼠器官，原位，或皮下注射人类肿瘤样MSK-PCA3。 这些研究不仅将为未来逆转CRPC患者耐药性的治疗策略提供信息，而且 也应该为我的培训目标提供一个独特的平台。在我的主要导师邓肯博士的指导下。 查尔斯·索耶斯和我的顾问委员会，我希望提高我在高级计算方面的能力， 癌症建模和基因编辑，以及床边翻译。再加上丰富的科学环境和 在MSKCC的大量资源，我的研究和培训应该使我能够实现我成为 在此资助期结束前，在泌尿生殖系统肿瘤学方面独立资助一名医生兼研究员。

PROJECT SUMMARY Despite the remarkable successes of targeted cancer therapies, certain cancers, including lung, breast, and prostate cancer and melanoma, invariably become resistant to therapy. One mechanism of secondary resistance—lineage plasticity—arises when cells transition into aggressive states, and, in the case of prostate cancer, acquire a neuroendocrine histology. This results in a rapid downhill course for a subset of the so–termed castrate–resistant prostate cancer (CRPC) patients. This, in essence, not only poses a clinical challenge, but also confronts us with a wide–open biological question—what are the molecular underpinnings of lineage plasticity, and importantly, can the process be reversed? We have very recently documented that the activation of JAK/STAT and FGFR signaling pathways promote lineage plasticity and result in complete insensitivity to androgen receptor signaling inhibitors (ARSIs) [*Chan, *Zaidi, et al., Science, 2022, PMID: 35981096, *co– first authors]. Importantly, we found that FDA–approved inhibitors of JAK/STAT (ruxolitinib) and FGFR (erdafitinib) synergize to reverse lineage plasticity and restore ARSI sensitivity. We therefore hypothesize that signals downstream of JAK/STAT and FGFR, including novel transcription factors, interact to promote lineage plasticity, and their timed perturbation can reverse plasticity and ARSI insensitivity. Thus, in Specific Aim 1, to study how FGFR signals synergize with JAK/STAT to impart plasticity, we will use chemical inhibitors and CRISPR–Cas9 to delete specific molecules in TP53/RB1–null mouse and human tumor organoids. Specific Aim 2 will focus on further deconvoluting the molecular complexity of lineage plasticity through unbiased single cell paired RNA and ATAC (multiome) sequencing in murine organoids. We expect to identify novel transcription factors and study their DNA accessibility post–TP53/RB1 deletion across the evolution of lineage plasticity, with and without ruxolitinib and/or erdafitinib. In Specific Aim 3, in proof–of–concept in vivo studies, we will examine the efficacy of combined treatment with ruxolitinib plus erdafitinib in reversing lineage plasticity and restoring ARSI sensitivity. For this, the ruxolitinib+erdafitinib combination will be studied in NOD SCID mice grafted either with TP53/RB1–null murine organoids, orthotopically, or with the human tumoroid MSK–PCA3, subcutaneously. These studies will not only inform future therapeutic strategies to subvert drug resistance in CRPC patients but should also provide a unique platform for my Training Aims. Under the tutelage of my primary mentor, Dr. Charles Sawyers, and my Advisory Committee, I expect to enhance my competencies in advanced computation, cancer modeling and genetic editing, and bedside translation. Together with the rich scientific environment and vast array of resources at MSKCC, my research and training should position me to achieve my goal of becoming an independently funded physician–investigator in genitourinary oncology by the end of this grant period.