Han Xiao, Shang Donghao, Han Tiandong, Xu Xiuhong, Tian Ye
Department of Urology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, P.R. China.
Exp Ther Med. 2014 Jul;8(1):267-273. doi: 10.3892/etm.2014.1691. Epub 2014 Apr 25.
The aim of the present study was to investigate the antiproliferative effects of interferon (IFN)-α and rapamycin (RPM) on renal cell carcinoma (RCC) cells and examine the synergistic growth suppression conferred by IFN-α and RPM. The effects of IFN-α and/or RPM on RCC cells were determined using a WST-1 assay and the synergy of IFN-α and RPM against three RCC cell lines was analyzed with isobolographic analysis. The expression of mammalian target of rapamycin (mTOR) was downregulated by RNAi, and the expression and phosphorylation of proteins in the mTOR pathway following treatment with IFN-α and/or RPM was examined by western blot analysis. The observations indicated that IFN-α significantly increased the susceptibility of RCC cells to RPM and the synergistic effect of IFN-α and RPM against RCC cells was confirmed in all three RCC cell lines. The mTOR pathway was shown to be associated with the synergistic effect of IFN-α and RPM against RCC. IFN-α and RPM alone decreased the phosphorylation of mTOR, p70 S6 kinase, S6 and 4E binding protein 1, and IFN-α significantly enhanced the RPM-induced suppression of the mTOR pathway. However, in RCC cells with low mTOR activity, the synergy of IFN-α and RPM was eliminated. Therefore, the results of the present study indicate that the mTOR pathway plays an important role in the synergistic effect of IFN-α and RPM against RCC cells. Thus, mTOR may serve as an effective therapeutic target in the treatment of advanced RCC.
本研究的目的是探讨干扰素（IFN）-α和雷帕霉素（RPM）对肾细胞癌（RCC）细胞的抗增殖作用，并研究IFN-α和RPM联合使用时产生的协同生长抑制作用。采用WST-1法测定IFN-α和/或RPM对RCC细胞的作用，并通过等效线图分析来分析IFN-α和RPM对三种RCC细胞系的协同作用。通过RNA干扰下调雷帕霉素靶蛋白（mTOR）的表达，并通过蛋白质印迹分析检测IFN-α和/或RPM处理后mTOR信号通路中蛋白质的表达和磷酸化情况。观察结果表明，IFN-α显著增加了RCC细胞对RPM的敏感性，并且在所有三种RCC细胞系中均证实了IFN-α和RPM对RCC细胞的协同作用。结果显示，mTOR信号通路与IFN-α和RPM对RCC的协同作用相关。单独使用IFN-α和RPM均可降低mTOR、p70 S6激酶、S6和4E结合蛋白1的磷酸化水平，并且IFN-α显著增强了RPM对mTOR信号通路的抑制作用。然而，在mTOR活性较低的RCC细胞中，IFN-α和RPM的协同作用消失。因此，本研究结果表明，mTOR信号通路在IFN-α和RPM对RCC细胞的协同作用中起重要作用。因此，mTOR可能是晚期RCC治疗中的一个有效治疗靶点。
