Kameyama Koji, Horie Kengo, Mizutani Kosuke, Kato Taku, Fujita Yasunori, Kawakami Kyojiro, Kojima Toshio, Miyazaki Tatsuhiko, Deguchi Takashi, Ito Masafumi
Department of Urology, Gifu University Graduate School of Medicine, Gifu, Gifu 501-1193, Japan.
Research Team for Mechanism of Aging, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173-0015, Japan.
Int J Oncol. 2017 Jan;50(1):75-84. doi: 10.3892/ijo.2016.3781. Epub 2016 Nov 24.
Advanced bladder cancer is treated mainly with gemcitabine and cisplatin, but most patients eventually become resistance. Androgen receptor (AR) signaling has been implicated in bladder cancer as well as other types of cancer including prostate cancer. In this study, we investigated the expression and role of AR in gemcitabine-resistant bladder cancer cells and also the potential of enzalutamide, an AR inhibitor, as a therapeutic for the chemoresistance. First of all, we established gemcitabine-resistant T24 cells (T24GR) from T24 bladder cancer cells and performed gene expression profiling. Microarray analysis revealed upregulation of AR expression in T24GR cells compared with T24 cells. AR mRNA and protein expression was confirmed to be increased in T24GR cells, respectively, by quantitative RT-PCR and western blot analysis, which was associated with more potent AR transcriptional activity as measured by luciferase reporter assay. The copy number of AR gene in T24GR cells determined by PCR was twice as many as that of T24 cells. AR silencing by siRNA transfection resulted in inhibition of proliferation of T24GR cells. Cell culture in charcoal-stripped serum and treatment with enzalutamide inhibited growth of T24GR cells, which was accompanied by cell cycle arrest. AR transcriptional activity was found to be reduced in T24GR cells by enzalutamide treatment. Lastly, enzalutamide also inhibited cell proliferation of HTB5 bladder cancer cells that express AR and possess intrinsic resistance to gemcitabine. Our results suggest that enzalutamide may have the potential to treat patients with advanced gemcitabine-resistant bladder cancer with increased AR expression.
晚期膀胱癌主要采用吉西他滨和顺铂进行治疗，但大多数患者最终会产生耐药性。雄激素受体（AR）信号通路在膀胱癌以及包括前列腺癌在内的其他类型癌症中均有涉及。在本研究中，我们调查了AR在吉西他滨耐药膀胱癌细胞中的表达及作用，以及AR抑制剂恩杂鲁胺作为化疗耐药治疗药物的潜力。首先，我们从T24膀胱癌细胞中建立了吉西他滨耐药的T24细胞（T24GR），并进行了基因表达谱分析。微阵列分析显示，与T24细胞相比，T24GR细胞中AR表达上调。通过定量RT-PCR和蛋白质印迹分析分别证实，T24GR细胞中AR mRNA和蛋白质表达增加，这与荧光素酶报告基因检测所测得的更强的AR转录活性相关。通过PCR测定，T24GR细胞中AR基因的拷贝数是T24细胞的两倍。通过siRNA转染使AR沉默导致T24GR细胞增殖受到抑制。在经活性炭处理的血清中进行细胞培养并用恩杂鲁胺处理可抑制T24GR细胞的生长，这伴随着细胞周期停滞。发现用恩杂鲁胺处理后，T24GR细胞中的AR转录活性降低。最后，恩杂鲁胺也抑制了表达AR且对吉西他滨具有固有耐药性的HTB5膀胱癌细胞的增殖。我们的结果表明，恩杂鲁胺可能有潜力治疗AR表达增加的晚期吉西他滨耐药膀胱癌患者。
