Juengel Eva, Kim Dana, Makarević Jasmina, Reiter Michael, Tsaur Igor, Bartsch Georg, Haferkamp Axel, Blaheta Roman A
Department of Urology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany.
J Cell Mol Med. 2015 Feb;19(2):430-41. doi: 10.1111/jcmm.12471. Epub 2014 Dec 2.
Sequential application of target drugs is standard procedure after renal cell carcinoma (RCC) patients develop resistance. To optimize the sequence, antitumour effects of the mTOR inhibitor RAD001 or the tyrosine kinase inhibitor (TKI) sorafenib on RCC cells with acquired resistance to the TKI sunitinib was evaluated. RCC cells were exposed to 1 μM sunitinib for 24 hrs (as control) and for 8 weeks (to induce resistance) and then switched to RAD001 (5 nM) or sorafenib (5 μM) for a further 8 weeks. Tumour cell growth, cell cycle progression, cell cycle regulating proteins and intracellular signalling were then investigated. Short-term application of sunitinib (24 hrs) induced cell growth blockade with accumulation in the G2/M phase. RCC cells became resistant to sunitinib after 8 weeks, demonstrated by accelerated cell growth along with enhanced cdk1, cdk2, loss of p27, activation of Akt, Rictor and Raptor. Switching to sorafenib only slightly reduced growth of the sunitinib resistant RCC cells and molecular analysis indicated distinct cross-resistance. In contrast, full response was achieved when the cancer cells were treated with RAD001. p19 and p27 strongly increased, phosphorylated Akt, Rictor and Raptor decreased and the tumour cells accumulated in G0/G1. It is concluded that an mTOR-inhibitor for second-line therapy could be the strategy of choice after first-line sunitinib failure.
在肾细胞癌（RCC）患者出现耐药后，序贯应用靶向药物是标准治疗程序。为了优化用药顺序，评估了mTOR抑制剂RAD001或酪氨酸激酶抑制剂（TKI）索拉非尼对已获得对TKI舒尼替尼耐药的RCC细胞的抗肿瘤作用。将RCC细胞暴露于1μM舒尼替尼24小时（作为对照）和8周（以诱导耐药），然后再切换至RAD001（5 nM）或索拉非尼（5μM），持续8周。随后研究肿瘤细胞生长、细胞周期进程﹑细胞周期调节蛋白和细胞内信号传导。短期应用舒尼替尼（24小时）可诱导细胞生长阻滞并使细胞积聚于G2/M期。8周后RCC细胞对舒尼替尼产生耐药，表现为细胞生长加速，同时伴有cdk1、cdk2增强，p27缺失，Akt、Rictor和Raptor激活。切换至索拉非尼仅轻微降低了对舒尼替尼耐药的RCC细胞的生长，分子分析表明存在明显的交叉耐药。相比之下，当癌细胞用RAD001治疗时则实现了完全缓解。p19和p27显著增加，磷酸化的Akt、Rictor和Raptor减少，肿瘤细胞积聚于G0/G1期。得出的结论是，在一线舒尼替尼治疗失败后，二线治疗选用mTOR抑制剂可能是首选策略。
