Clinical Pharmacology and Pharmacogenetics Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
Medical Oncology Unit, Department of Translational Research and New Technologies in Medicine, University of Pisa, Pisa, Italy.
Eur Urol. 2017 Apr;71(4):680-687. doi: 10.1016/j.eururo.2016.08.012. Epub 2016 Oct 10.
The androgen receptor splice variant 7 (AR-V7) is associated with resistance to hormonal therapy in castration-resistant prostate cancer (CRPC). Due to limitations of the methods available for AR-V7 analysis, the identification of a reliable detection method may facilitate the use of this biomarker in clinical practice.
To confirm AR-V7 as a predictor of resistance to hormonal therapy and develop a new approach to assess AR-V7 by highly sensitive digital droplet polymerase chain reaction (ddPCR) in plasma-derived exosomal RNA.
DESIGN, SETTING, AND PARTICIPANTS: Plasma samples were collected from 36 CRPC patients before they began second-line hormonal treatment. Exosomes were isolated and RNA extracted for analysis of AR-V7 by ddPCR.
The absolute target gene concentration as copies per milliliter (copies/ml) was determined by ddPCR. Statistical analyses were performed with SPSS software (IBM Corp., Armonk, NY, USA).
A total of 26 patients received abiraterone and 10 enzalutamide; 39% of patients were found to be AR-V7 positive (AR-V7). Median progression-free survival was significantly longer in AR-V7 negative (AR-V7) versus AR-V7 patients (20 vs 3 mo; p<0.001). Overall survival was significantly shorter in AR-V7 participants at baseline compared with AR-V7 participants (8 mo vs not reached; p<0.001).
This study demonstrates that plasma-derived exosomal RNA is a reliable source of AR-V7 that can be detected sensitively by ddPCR assay. We also showed that resistance to hormonal therapy may be predicted by AR-V7, making it a clinically relevant biomarker.
We report a first study on a method for androgen receptor splice variant 7 (AR-V7) detection in RNA extracted from cancer cell vesicles released in blood. Results confirmed the role of AR-V7 as a predictive biomarker of resistance to hormonal therapy. Our assay showed that vesicles are a reliable source of AR-V7 RNA and that the method is fast, highly sensitive, and affordable.
雄激素受体剪接变异体 7（AR-V7）与去势抵抗性前列腺癌（CRPC）对激素治疗的耐药性有关。由于目前用于 AR-V7 分析的方法存在局限性，因此确定一种可靠的检测方法可能有助于该生物标志物在临床实践中的应用。
证实 AR-V7 是对激素治疗耐药的预测因子，并通过高度敏感的数字液滴聚合酶链反应（ddPCR）在血浆衍生的外泌体 RNA 中开发一种新的方法来评估 AR-V7。
设计、设置和参与者：在开始二线激素治疗之前，从 36 名 CRPC 患者中采集血浆样本。分离外泌体并提取 RNA 用于 ddPCR 分析 AR-V7。
通过 ddPCR 确定绝对靶基因浓度（以拷贝/毫升[copies/ml]表示）。使用 SPSS 软件（IBM 公司，纽约州阿蒙克）进行统计分析。
共有 26 名患者接受阿比特龙治疗，10 名患者接受恩杂鲁胺治疗；39%的患者被发现 AR-V7 阳性（AR-V7）。AR-V7 阴性（AR-V7）患者的无进展生存期明显长于 AR-V7 患者（20 与 3 个月；p<0.001）。与 AR-V7 患者相比，基线时 AR-V7 患者的总生存期明显缩短（8 个月与未达到；p<0.001）。
本研究表明，血浆衍生的外泌体 RNA 是一种可靠的 AR-V7 来源，可以通过 ddPCR 检测法灵敏地检测到。我们还表明，激素治疗耐药性可以通过 AR-V7 预测，使其成为一种具有临床意义的生物标志物。
我们报告了一项关于从血液中释放的癌细胞囊泡中提取的 RNA 中检测雄激素受体剪接变体 7（AR-V7）的方法的首次研究。结果证实了 AR-V7 作为激素治疗耐药性预测生物标志物的作用。我们的检测方法表明，囊泡是 AR-V7 RNA 的可靠来源，并且该方法快速、高度敏感且价格合理。
