Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.
Rudolf Becker Laboratory for Prostate Cancer Research, Medical Faculty, University of Bonn, Bonn, Germany.
Oncogene. 2022 Jul;41(30):3747-3760. doi: 10.1038/s41388-022-02382-y. Epub 2022 Jun 27.
Aberrant transcriptional activity of androgen receptor (AR) is one of the dominant mechanisms for developing of castration-resistant prostate cancer (CRPC). Analyzing AR-transcriptional complex related to CRPC is therefore important towards understanding the mechanism of therapy resistance. While studying its mechanism, we observed that a transmembrane protein called neuropilin-2 (NRP2) plays a contributory role in forming a novel AR-transcriptional complex containing nuclear pore proteins. Using immunogold electron microscopy, high-resolution confocal microscopy, chromatin immunoprecipitation, proteomics, and other biochemical techniques, we delineated the molecular mechanism of how a specific splice variant of NRP2 becomes sumoylated upon ligand stimulation and translocates to the inner nuclear membrane. This splice variant of NRP2 then stabilizes the complex between AR and nuclear pore proteins to promote CRPC specific gene expression. Both full-length and splice variants of AR have been identified in this specific transcriptional complex. In vitro cell line-based assays indicated that depletion of NRP2 not only destabilizes the AR-nuclear pore protein interaction but also inhibits the transcriptional activities of AR. Using an in vivo bone metastasis model, we showed that the inhibition of NRP2 led to the sensitization of CRPC cells toward established anti-AR therapies such as enzalutamide. Overall, our finding emphasize the importance of combinatorial inhibition of NRP2 and AR as an effective therapeutic strategy against treatment refractory prostate cancer.
雄激素受体（AR）的转录活性异常是去势抵抗性前列腺癌（CRPC）发展的主要机制之一。因此，分析与 CRPC 相关的 AR 转录复合物对于理解治疗抵抗的机制非常重要。在研究其机制的过程中，我们观察到一种跨膜蛋白，称为神经纤毛蛋白-2（NRP2），在形成包含核孔蛋白的新型 AR 转录复合物中起辅助作用。通过免疫金电子显微镜、高分辨率共聚焦显微镜、染色质免疫沉淀、蛋白质组学和其他生化技术，我们描绘了 NRP2 的特定剪接变体在配体刺激下发生 SUMO 化并易位到核内膜的分子机制。这种 NRP2 的剪接变体然后稳定 AR 和核孔蛋白之间的复合物，以促进 CRPC 特异性基因表达。在这个特定的转录复合物中已经鉴定出全长和剪接变体的 AR。体外细胞系测定表明，NRP2 的耗竭不仅会破坏 AR-核孔蛋白相互作用，还会抑制 AR 的转录活性。通过体内骨转移模型，我们表明抑制 NRP2 会导致 CRPC 细胞对已建立的抗 AR 治疗（如恩杂鲁胺）产生敏感性。总的来说，我们的发现强调了联合抑制 NRP2 和 AR 作为治疗难治性前列腺癌的有效治疗策略的重要性。
