Neuroendocrine differentiation post anti-androgenic therapy: Role of Tribbles 2

抗雄激素治疗是原发性和播散性前列腺癌的主要治疗方法。FDA- 获批的Enzalutamide（Xtandi）处于抗雄激素药物的最前沿，具有上级患者特征， 大多数规定。然而，Enzalutamide耐药前列腺癌（ERPC）总是会发生， 不可治愈的，并负责大多数前列腺癌相关的死亡，强调管理， ERPC是一种未满足的紧急医疗需求。开发一种有效的治疗ERPC是痛苦的 缺乏对关键分子靶点的正确理解，无法有效杀死ERPC细胞。以识别 潜在的新靶点，我们开发了一种ERPC模型，该模型模拟了接受ERPC治疗的患者的临床状况。 标准Enzalutamide治疗。我们用恩杂鲁胺治疗雄激素敏感性前列腺癌细胞， 长期培养以产生细胞系（LNCaP-ENR、PCa-2B-ENR），这些细胞系不再对临床相关的 恩杂鲁胺剂量。全面的基因表达分析显示ERPC细胞过度表达 Tribbles 2（Trib 2），是Tribbles假激酶家族的成员。Trib 2在PDX中也有过表达 和患者前列腺肿瘤。强迫过表达Trib 2导致增强的 前列腺癌细胞生长和对恩杂鲁胺、阿帕鲁胺、达罗鲁米特和阿比特龙的耐药性。 Trib 2的抑制使耐药细胞对enzalutamide重新敏感，并降低其活力，表明可能的 Trib 2与Enzalutamide耐药性发生之间存在直接联系。有趣的是，Trib 2下调Rb 1， 和p53，同时诱导神经元转录因子（N-Myc，BRN 2）和神经内分泌（NE）标记物 （嗜铬粒蛋白A、神经元特异性烯醇化酶和突触素）。抑制N-Myc或BRN 2使再致敏 对恩杂鲁胺有抗性的细胞。这些发现表明，Trib 2驱动细胞从管腔型转分化， NE表型对抗雄激素产生抗性。因此，Trib 2成为一种新的，有前途的分子 ERPC-NE治疗靶点。然而，Trib 2在NE分化中的机制和作用需要进一步研究。 使用适当的体外和体内模型测定。因此，本提案的设计将 表征Trib 2如何诱导NE分化（目的1），确定Trib 2抑制对增强的NE分化的影响。 ERPC肿瘤生长和远处转移（目的2），并测试Trib 2基因靶向对前列腺的影响 使用转基因Trib 2敲除小鼠模型的肿瘤进展和NE分化（Aim 3）。完成 这些目标将确立Trib 2作为治疗诱导NE分化的分子驱动因子， 为恩杂鲁胺耐药、NE型、致死性前列腺癌开发新的靶向治疗策略。

Anti-androgenic therapy is the mainstay for both primary and disseminated forms of prostate cancer. FDA- approved enzalutamide (Xtandi) is at the forefront of anti-androgens with superior patient profile and is the one most prescribed. However, enzalutamide resistant prostate cancer (ERPC) invariably develops, which is incurable and responsible for most of the prostate cancer-related deaths, underscoring that management of ERPC is an unmet and urgent medical need. Development of an effective therapy against ERPC is suffering from lack of proper understanding about critical molecular targets to effectively kill ERPC cells. To identify potential new targets, we developed an ERPC model which mimics the clinical conditions in patients undergoing standard enzalutamide therapy. We treated androgen-sensitive prostate cancer cells with enzalutamide in long- term culture to generate cell lines (LNCaP-ENR, PCa-2B-ENR) which are no longer sensitive to clinically relevant doses of enzalutamide. Comprehensive gene expression analysis revealed that the ERPC cells overexpress Tribbles 2 (Trib2), a member of the tribbles pseudokinase family. Overexpression of Trib2 was also found in PDX and patient prostate tumors after enzalutamide treatment. Forced overexpression Trib2 results in enhanced prostate cancer cell growth and resistance to enzalutamide, apalutamide, darolutamide and abiraterone. Inhibition of Trib2 re-sensitizes resistant cells to enzalutamide and decreases their viability, indicating a possible direct link between Trib2 and development of enzalutamide resistance. Interestingly, Trib2 downregulates Rb1 and p53, while induces the neuronal transcription factors (N-Myc, BRN2) and the neuroendocrine (NE) markers (Chromogranin A, Neuron-specific enolase and Synaptophysin). Inhibition of N-Myc or BRN2 re-sensitizes resistant cells to enzalutamide. These findings suggest that Trib2 drives cellular trans-differentiation from luminal to NE phenotype to pose resistance to anti-androgens. Thus, Trib2 emerges as a novel, promising molecular target for therapy of ERPC-NE. However, the mechanism and role of Trib2 in NE differentiation needs to be determined using appropriate in vitro and in vivo models. Thus, this proposal has been designed which will characterize how Trib2 induces NE differentiation (Aim 1), determine the impact of Trib2 inhibition in enhanced ERPC tumor growth and distant metastasis (Aim 2), and test the impact of Trib2 gene-targeting on prostate tumor progression and NE differentiation using transgenic Trib2 knockout mouse models (Aim 3). Accomplishing these goals will establish Trib2 as a molecular driver for treatment-induced NE differentiation and will help develop a new targeted therapeutic strategy for enzalutamide resistant, NE type, lethal prostate cancer.