The role of focal adhesion kinase in therapy resistant prostate tumors

摘要 治疗诱导的神经内分泌前列腺癌(t-NEPC)是前列腺癌患者的一个亚型 结果。除了全身化疗和姑息治疗外，没有一种定向治疗是成功的。 反映了我们对NEPC是如何发展的有限的了解。 我们已经报道了一个由神经剪接因子SRRM4驱动的t-NEPC特异性RNA剪接程序，它 推动T-NEPC发展。这种剪接程序对整个基因组的癌细胞都有影响，因为它 对表观遗传调节因子、转录因子和癌症干细胞调节因子的功能进行重新编程， 导致前列腺癌细胞获得神经内分泌谱系并独立于AR 发出求生的信号。FAK(粘着斑激酶)基因剪接是t-NEPC剪接程序的一部分， 由此神经FAK剪接变异体在t-NEPC中高表达。相对于本构FAK(FAK-c) 剪接变异体，神经性FAK促进神经内分泌分化和AR非依赖性肿瘤生长。进一步 序列分析表明，这些神经FAK主要通过缺氧转录组通过HIF-1发挥作用。 重要的是，我们发现当肿瘤细胞获得神经FAK信号时，它们对FAK变得脆弱 这是一种激酶抑制剂。 这些发现表明，FAK基因的异常RNA剪接促进了t-NEPC的进展，并且 靶向FAK信号可能为t-NEPC患者提供一种新的治疗选择。我们已经开发了四个 具体目的是检验这一假说。在目标1中，我们将建立神经FAK剪接的临床相关性 与神经内分泌癌组织学、去势抵抗前列腺癌进展、肿瘤的关系 转移和患者的临床结果。在目标2中，我们将破译SRRM4 调节神经FAK的剪接，并确定调节RNA的外在治疗诱导的应激条件 神经FAK的拼接。在目标3中，我们将描述几个已知的FAK相关的激酶信号 通过蛋白质合成或蛋白质降解途径增强HIF-1蛋白的表达。我们会 还使用全球蛋白质组分析来描述神经FAK相互作用及其激活的磷- 促进t-nepc进展的蛋白质组学。在目标4中，我们将研究FAK抑制剂是否可以阻断神经 FAK在NEPC细胞中的作用，并检测FAK抑制剂是否可以作为一种联合疗法来阻断t- NEPC异种移植生长。 综上所述，这些研究将对前列腺癌细胞如何发展治疗获得新的机械性见解- 并提名FAK抑制剂作为治疗耐药前列腺癌的潜在药物。

Abstract Treatment-induced neuroendocrine prostate cancer (t-NEPC) is a subgroup of prostate tumors with poor patient outcomes. Beyond systemic chemotherapy and palliative care, no targeted therapy has been successful reflecting our limited knowledge of how NEPC is developed. We have reported a t-NEPC-specific RNA splicing program driven by the neural splicing factor SRRM4, which promotes t-NEPC development. This splicing program has genome-wide impacts on cancer cells as it reprograms the functions of epigenetic modulators, transcriptional factors, and cancer stem cell regulators, resulting in prostate adenocarcinoma cells acquiring neuroendocrine lineage and becoming independent of AR signalling for survival. The FAK (focal adhesion kinase) gene splicing is a part of the t-NEPC splicing program, whereby neural FAK splice variants are highly expressed in t-NEPC. In contrast to the constitutive FAK (FAK-c) splice variant, neural FAKs promote neuroendocrine differentiation and AR-independent tumor growth. Further RNA-seq analysis indicated that these neural FAKs act mainly through a hypoxic transcriptome via HIF-1. Importantly, we found that when tumor cells gain the neural FAK signaling, they become vulnerable to FAK kinase inhibitors. These findings suggest that aberrant RNA splicing of the FAK gene promotes t-NEPC progression and that targeting the FAK signal may provide a new therapeutic option for t-NEPC patients. We have developed four specific aims to test this hypothesis. In Aim 1, we will establish the clinical relevance of neural FAK splicing in association with neuroendocrine carcinoma histology, castrate-resistant prostate cancer progression, tumor metastasis, and patient clinical outcomes. In Aim 2, we will decipher the intrinsic mechanism by which SRRM4 regulates neural FAK splicing, and determine the extrinsic therapy-induced stress conditions that regulate RNA splicing of neural FAKs. In Aim 3, we will characterize several FAK-associated kinase signaling that were known to enhance HIF-1 protein expression through either protein synthesis or protein degradation pathways. We will also employ global proteomic analyses to profile neural FAK interactomes and their activated phosphor- proteomics that promote t-NEPC progression. In Aim 4, we will study whether FAK inhibitors can block neural FAK actions in NEPC cells and test whether FAK inhibitors can be used as a combination therapy to block t- NEPC xenograft growth. In summary, these studies will gain new mechanistic insight into how prostate cancer cells develop therapy- resistance and nominate FAK inhibitors to be potential therapeutics for therapy-resistant prostate tumors.