A novel mitotic regulatory axis in neuroendocrine prostate cancer

神经内分泌前列腺癌（NEPC）是转移性去势抵抗性前列腺癌的一个致命亚类 （mCRPC），具有侵袭性临床特征和较差的总生存期。虽然很少发生从头， 来自前列腺腺癌（PAC）的治疗相关NEPC（t-NEPC）可发生在约25%或更多的患者中 晚期mCRPC，其众所周知难以治疗并且对抗雄激素疗法具有抗性。目前迫切 需要新的靶点和疗法。在这项研究中，我们试图确定PKD在t-NEPC中的作用， PKD抑制剂治疗t-NEPC的治疗潜力。PRKD扩增和/或上调 近60%的NEPC肿瘤。PKD，尤其是PKD 2，蛋白表达和活性在NEPC中升高， 肿瘤组织PKD 2/3（NEPC细胞中的主要PKD）的敲低降低了NE生物标志物，抑制了 细胞增殖/存活和体内肿瘤生长，而PKD 2过表达通过以下途径促进NE编程： 诱导NE标记和抑制AR靶向基因，这抵消了N-myc的作用，N-myc是一个主要的驱动因子， 关于NEPC PKD 2的过表达也赋予雄激素非依赖性，并降低对 在雄激素敏感的PAC细胞中使用化疗剂。我们进一步鉴定了AURKA/Aurora-A激酶， PKD的新下游靶点。Aurora-A是一种关键的有丝分裂调节因子，与 NEPC肿瘤中的N-myc通过结合和稳定N-myc促进NEPC进展。我们的数据显示， Aurora-A/N-myc复合物的稳定需要PKD活性。PKD表型复制的过度表达， 在前列腺癌细胞中，PKD的敲低阻断了N-myc的功能，这意味着PKD在前列腺癌细胞中的作用。 调节Aurora-A/N-myc复合物。此外，PKD对Aurora-A的稳定是有丝分裂所必需的。 进入，这是一种可能导致紫杉烷类药物耐药性的功能。重要的是，PKD的抑制由 PKD抑制剂CRT 0066101（CRT）阻断NEPC肿瘤细胞增殖/存活、迁移/侵袭， 抑制NEPC肿瘤异种移植物的生长并减少体内骨转移。CRT还协同 与多西他赛和PI 3 K抑制剂在NEPC细胞中的作用，暗示它们在联合治疗中的潜在用途。基于 根据这些发现，我们推测PKD表达和活性的增加促进了有丝分裂程序化， 和Aurora-A/N-myc复合物的稳定性来影响N-myc驱动的t-NEPC进展。我们进一步 认为PKD抑制剂将为NEPC的治疗提供新的思路。我们建议：目标 1.确定PKD作为t-NEPC的潜在生物标志物，并评估PKD激活的 有丝分裂程序对t-NEPC治疗耐药性的影响。目标2.检验PKD促进t-NEPC的假设 通过稳定Aurora-A/N-myc复合物来影响N-myc驱动的肿瘤发生。目标3。确定 PKD抑制剂在转移性NEPC小鼠模型和TRAMP中治疗NEPC的治疗潜力 小鼠

Neuroendocrine prostate cancer (NEPC) is a lethal subset of metastatic castration-resistant prostate cancer (mCRPC) with aggressive clinical features and poor overall survival. Although rarely occurs de novo, the treatment-related NEPC (t-NEPC) derived from prostatic adenocarcinoma (PAC) can arise in about 25% or more late stage mCRPC, which is notoriously hard to treat and resistant to antiandrogen therapy. There is an urgent need for novel targets and therapies. In this study, we seek to determine the roles of PKD in t-NEPC and exploit the therapeutic potential of PKD inhibitors for the treatment of t-NEPC. PRKDs were amplified and/or upregulated in nearly 60% of NEPC tumors. PKD, particularly PKD2, protein expression and activity were elevated in NEPC tumor tissues. Knockdown of PKD2/3, the predominant PKDs in NEPC cells, decreased NE biomarkers, inhibited cell proliferation/survival, and tumor growth in vivo, while PKD2 overexpression promoted NE programing by inducing NE markers and suppressing AR-targeted genes, which paralleled the effects of N-myc, a major driver of NEPC. Overexpression of PKD2 also conferred androgen independence and reduced sensitivity to chemotherapeutic agents in in androgen-sensitive PAC cells. We further identified AURKA/Aurora-A kinase as a novel downstream target of PKD. Aurora-A, a key mitotic regulator that is co-amplified and upregulated with N-myc in NEPC tumors, promotes NEPC progression by binding and stabilizing N-myc. Our data indicated that PKD activity was required for the stabilization of Aurora-A/N-myc complex. Overexpression of PKD phenocopied, while knockdown of PKD blocked, the functions of N-myc in prostate cancer cells, implying a role of PKD in regulating Aurora-A/N-myc complex. Moreover, the stabilization of Aurora-A by PKD is necessary for mitotic entry, a function that may contribute to taxane-based therapy resistance. Importantly, inhibition of PKD by the PKD inhibitor CRT0066101 (CRT) blocked NEPC tumor cell proliferation/survival, migration/invasion, and suppressed the growth of NEPC tumor xenografts and reduced bone metastasis in vivo. CRT also synergized with docetaxel and PI3K inhibitor in NEPC cells, implying their potential use in combination therapy. Based on these findings, we hypothesize that increased PKD expression and activity promote mitotic programing and Aurora-A/N-myc complex stability to impinge upon N- myc-driven t-NEPC progression. We further posit that PKD inhibitors will derive a new therapeutic strategy to better treat NEPC. We propose to: Aim 1. Determine PKD as a potential biomarker for t-NEPC and assess the functional relevance of PKD-activated mitotic programing to therapeutic resistance in t-NEPC. Aim 2. Test the hypothesis that PKD promotes t-NEPC by stabilizing Aurora-A/N-myc complex to impinge upon N-myc-driven oncogenesis. Aim 3. Determine the therapeutic potential of PKD inhibitors for treatment of NEPC in a metastatic NEPC mouse model and TRAMP mice.