Department of Urology, University at Lübeck, University Hospital Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany.
Oncol Rep. 2011 Mar;25(3):763-8. doi: 10.3892/or.2011.1146. Epub 2011 Jan 14.
Bladder cancer and head and neck squamous cell carcinoma (HNSCC) are frequent but lack efficient therapies especially in advanced disease. Almost no studies on mTOR function and inhibition in these tumor entities have been reported. We examined the gene and protein expression levels of mTOR and its activated form (pmTOR) in three human bladder carcinoma cell lines (RT-4, T24, EJ28) and three HNSCC cell lines (PCI-1, PCI-13, BHY). Furthermore, the consequences of mTOR inhibition by mTOR-specific siRNAs and the mTOR inhibitor temsirolimus were analysed in vitro using immunohistochemical Ki-67 staining, mTOR and pmTOR western blot analysis, MTT assay, as well as cell cycle analysis with flow cytometry. Especially pmTOR protein expression levels showed marked differences between cell lines. siRNA transfection was associated with dose-dependent target protein reduction but not proliferation inhibition or apoptosis. On the contrary, temsirolimus significantly reduced cell viability and induced apoptosis and cell cycle arrest. According to these data, bladder cancer and HNSCC are promising tumor entities for mTOR inhibition with temsirolimus.
膀胱癌和头颈部鳞状细胞癌（HNSCC）较为常见，但缺乏有效的治疗方法，尤其是在晚期疾病中。几乎没有关于这些肿瘤实体中 mTOR 功能和抑制作用的研究。我们在三种人膀胱癌细胞系（RT-4、T24、EJ28）和三种 HNSCC 细胞系（PCI-1、PCI-13、BHY）中检测了 mTOR 及其激活形式（pmTOR）的基因和蛋白表达水平。此外，我们还使用免疫组化 Ki-67 染色、mTOR 和 pmTOR Western blot 分析、MTT 测定以及流式细胞术进行的细胞周期分析，在体外分析了 mTOR 特异性 siRNA 和 mTOR 抑制剂替西罗莫司对 mTOR 抑制的影响。特别是 pmTOR 蛋白表达水平在细胞系之间存在明显差异。siRNA 转染与剂量依赖性的靶蛋白减少相关，但与增殖抑制或凋亡无关。相反，替西罗莫司显著降低了细胞活力，并诱导了细胞凋亡和细胞周期停滞。根据这些数据，膀胱癌和 HNSCC 是具有应用替西罗莫司抑制 mTOR 潜力的有前途的肿瘤实体。
