Genetic Service, Cytogenetic Laboratory, Hospital Center of Trás-os-Montes and Alto Douro, Vila Real, Portugal.
J Toxicol Environ Health A. 2012;75(13-15):788-99. doi: 10.1080/15287394.2012.690325.
The purpose of this study was to determine whether everolimus, a rapamycin derivative, might significantly enhance the cytotoxicity of gemcitabine, an antitumor drug, in two human bladder-cancer cell lines. Human bladder-cancer T24 and 5637 cells were incubated with gemcitabine and everolimus in a range of concentrations either alone or in combination for 72 h. Flow cytometry, comet assay, MTT method and optical microscopy were used to assess cell proliferation, cell cycle, DNA damage, and morphological alterations. Gemcitabine exerted an inhibitory effect on T24 and 5637 cell proliferation, in a concentration-dependent manner. Everolimus significantly reduced proliferation of 5637 bladder cancer cells (IC₃₀) at 1 μM), whereas T24 demonstrated marked resistance to everolimus treatment. A significant antiproliferative effect was obtained combining gemcitabine (100 nM) with everolimus (0.05-2 μM) with an arrest of cell cycle at S phase. Furthermore, an increase in frequency of DNA damage, apoptotic bodies, and apoptotic cells was observed when T24 and 5637 cancer cells were treated simultaneously with both drugs. Data show that in vitro combination produced a more potent antiproliferative effect when compared with single drugs.
本研究旨在确定雷帕霉素衍生物依维莫司是否能显著增强两种人膀胱癌细胞系中抗肿瘤药物吉西他滨的细胞毒性。将人膀胱癌 T24 和 5637 细胞分别与吉西他滨和依维莫司在一系列浓度下单独或联合孵育 72 小时。采用流式细胞术、彗星试验、MTT 法和光学显微镜评估细胞增殖、细胞周期、DNA 损伤和形态改变。吉西他滨呈浓度依赖性抑制 T24 和 5637 细胞增殖。依维莫司能显著降低 5637 膀胱癌细胞的增殖（IC₅₀ 为 1 μM），而 T24 对依维莫司治疗表现出明显的耐药性。吉西他滨（100 nM）联合依维莫司（0.05-2 μM）可将细胞周期阻滞在 S 期，从而获得显著的抗增殖作用。此外，当两种药物同时作用于 T24 和 5637 癌细胞时，观察到 DNA 损伤、凋亡小体和凋亡细胞的频率增加。数据表明，与单药治疗相比，体外联合治疗产生了更强的抗增殖作用。
