Wang Yan, Liu Gaolei, Tong Dali, Parmar Henna, Hasenmayer Donald, Yuan Wenqiang, Zhang Dianzheng, Jiang Jun
Department of Urology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, PR China.
Department of Bio-Medical Sciences, Philadelphia College of osteopathic Medicine, Philadelphia, Pennsylvania.
Prostate. 2015 Aug 1;75(11):1187-96. doi: 10.1002/pros.23000. Epub 2015 Apr 20.
Metformin has been reported to inhibit the growth of different types of cancers, including prostate cancer. We were interested to understand if the effect of metformin on prostate cancer is AR-dependent and, if so, whether metformin could act synergistically with the other anti-AR agents to serve as a therapeutic regimen with high efficacy and low toxicity.
Cell viabilities and apoptosis were determined by MTT assay and annexin V-FITC staining, respectively, when the two human prostate cancer cell lines, the androgen-dependent LNCaP and the androgen-independent 22RV1 were treated with metformin alone or in combination with bicalutamide. Quantitative RT-PCR and western blotting assays were conducted to examine metformin effects on AR mRNA and protein levels, respectively. Chromatin immunoprecipitation (ChIP) assays were conducted to confirm the recruitment of AR to the ARE(s) located on the promoter region of the AR target gene PSA.
Metformin treatment reduced cell viability and enhanced apoptosis for both cell lines and additive effects were observed when LNCaP cells were treated with combined metformin and bicalutamide. Metformin down-regulated full-length AR protein in LNCaP cells. Both full-length and the truncated AR (AR-v7) were down-regulated by metformin in CWR22Rv1 cells. In both LNCaP and CWR22Rv1 cells, metformin repressed AR signaling pathway not by affecting AR protein degradation/stability, but rather through down-regulating the levels of AR mRNAs.
Metformin represses prostate cancer cell viability and enhances apoptosis by targeting the AR signaling pathway. Combinations of metformin and other anti-AR agents pose a potentially promising therapeutic approach for treatment of prostate cancers, especially the castrate-resistant prostate cancer, with high efficacy and low toxicity.
据报道，二甲双胍可抑制包括前列腺癌在内的不同类型癌症的生长。我们感兴趣的是了解二甲双胍对前列腺癌的作用是否依赖雄激素受体（AR），如果是，二甲双胍是否能与其他抗AR药物协同作用，以形成一种高效低毒的治疗方案。
当分别用二甲双胍单独处理或与比卡鲁胺联合处理雄激素依赖的LNCaP和雄激素非依赖的22RV1这两种人前列腺癌细胞系时，分别通过MTT法和膜联蛋白V-FITC染色来测定细胞活力和凋亡情况。进行定量逆转录聚合酶链反应（RT-PCR）和蛋白质印迹分析，分别检测二甲双胍对AR信使核糖核酸（mRNA）水平和蛋白质水平的影响。进行染色质免疫沉淀（ChIP）分析，以确认AR被招募到位于AR靶基因前列腺特异性抗原（PSA）启动子区域的雄激素反应元件（ARE）上。
二甲双胍处理降低了两种细胞系的细胞活力并增强了凋亡，当LNCaP细胞用二甲双胍和比卡鲁胺联合处理时观察到相加效应。二甲双胍下调了LNCaP细胞中全长AR蛋白。在CWR22Rv1细胞中，二甲双胍使全长和截短的AR（AR-v7）均下调。在LNCaP和CWR22Rv1细胞中，二甲双胍均不是通过影响AR蛋白降解/稳定性，而是通过下调AR mRNA水平来抑制AR信号通路。
二甲双胍通过靶向AR信号通路抑制前列腺癌细胞活力并增强凋亡。二甲双胍与其他抗AR药物联合使用，为治疗前列腺癌，尤其是去势抵抗性前列腺癌，提供了一种具有潜在前景的高效低毒治疗方法。
