Kawahara Takashi, Ide Hiroki, Kashiwagi Eiji, El-Shishtawy Kareem A, Li Yi, Reis Leonardo O, Zheng Yichun, Miyamoto Hiroshi
Department of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD; Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY.
Department of Pathology and Urology, Johns Hopkins University School of Medicine, Baltimore, MD.
Urol Oncol. 2016 Oct;34(10):432.e15-23. doi: 10.1016/j.urolonc.2016.05.016. Epub 2016 Jun 18.
Emerging preclinical evidence suggests that androgen-mediated androgen receptor (AR) signals promote bladder cancer progression. However, little is known about the efficacy of an AR signaling inhibitor, enzalutamide, in the growth of bladder cancer cells. In this study, we compared the effects of enzalutamide and 2 other classic antiandrogens, flutamide and bicalutamide, on androgen-induced bladder cancer cell proliferation, migration, and invasion as well as tumor growth in vivo.
Thiazolyl blue cell viability assay, flow cytometry, scratch wound-healing assay, transwell invasion assay, real-time polymerase chain reaction, and reporter gene assay were performed in AR-positive (e.g., UMUC3, TCCSUP, and 647V-AR) and AR-negative (e.g., UMUC3-AR-short hairpin RNA [shRNA], TCCSUP-AR-shRNA, 647V) bladder cancer lines treated with dihydrotestosterone and each AR antagonist. We also used a mouse xenograft model for bladder cancer.
Dihydrotestosterone increased bladder cancer cell proliferation, migration, and invasion indicating that endogenous or exogenous AR was functional. Enzalutamide, hydroxyflutamide, and bicalutamide showed similar inhibitory effects, without significant agonist activity, on androgen-mediated cell viability/apoptosis, cell migration, and cell invasion in AR-positive lines. No significant effects of dihydrotestosterone as well as AR antagonists on the growth of AR-negative cells were seen. Correspondingly, in UMUC3 cells, these AR antagonists down-regulated androgen-induced expression of AR, matrix metalloproteinase-2, and interleukin-6. Androgen-enhanced AR-mediated transcriptional activity was also blocked by each AR antagonist exhibiting insignificant agonist activity. In UMUC3 xenograft-bearing mice, oral gavage treatment with each antiandrogen retarded tumor growth, and only enzalutamide demonstrated a statistically significant suppression compared with mock treatment.
Our current data support recent observations indicating the involvement of the AR pathway in bladder cancer growth and further suggest that AR antagonists, including enzalutamide, are of therapeutic benefit in AR-positive bladder cancer.
新出现的临床前证据表明，雄激素介导的雄激素受体（AR）信号促进膀胱癌进展。然而，关于AR信号抑制剂恩杂鲁胺对膀胱癌细胞生长的疗效知之甚少。在本研究中，我们比较了恩杂鲁胺与其他两种经典抗雄激素药物氟他胺和比卡鲁胺对雄激素诱导的膀胱癌细胞增殖、迁移和侵袭以及体内肿瘤生长的影响。
在经二氢睾酮和每种AR拮抗剂处理的AR阳性（如UMUC3、TCCSUP和647V-AR）和AR阴性（如UMUC3-AR短发夹RNA[shRNA]、TCCSUP-AR-shRNA、647V）膀胱癌细胞系中进行噻唑蓝细胞活力测定、流式细胞术、划痕伤口愈合测定、Transwell侵袭测定、实时聚合酶链反应和报告基因测定。我们还使用了膀胱癌小鼠异种移植模型。
二氢睾酮增加了膀胱癌细胞的增殖、迁移和侵袭，表明内源性或外源性AR具有功能。恩杂鲁胺、羟基氟他胺和比卡鲁胺对AR阳性细胞系中雄激素介导的细胞活力/凋亡、细胞迁移和细胞侵袭显示出相似的抑制作用，且无明显激动剂活性。未观察到二氢睾酮以及AR拮抗剂对AR阴性细胞生长有显著影响。相应地，在UMUC3细胞中，这些AR拮抗剂下调了雄激素诱导的AR、基质金属蛋白酶-2和白细胞介素-6的表达。每种无明显激动剂活性的AR拮抗剂也阻断了雄激素增强的AR介导的转录活性。在携带UMUC3异种移植瘤的小鼠中，每种抗雄激素药物的灌胃治疗均延缓了肿瘤生长，与假处理相比，只有恩杂鲁胺表现出统计学上显著的抑制作用。
我们目前的数据支持最近的观察结果，即AR途径参与膀胱癌生长，并进一步表明包括恩杂鲁胺在内的AR拮抗剂对AR阳性膀胱癌具有治疗益处。
