Carew Jennifer S, Espitia Claudia M, Zhao Weiguo, Mita Monica M, Mita Alain C, Nawrocki Steffan T
Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio.
Division of Hematology/Oncology, Cancer Therapy and Research Center at The University of Texas Health Science Center at San Antonio, San Antonio, Texas.
Mol Cancer Ther. 2015 Jun;14(6):1404-13. doi: 10.1158/1535-7163.MCT-14-1036. Epub 2015 Mar 25.
Elevated expression of the antiapoptotic factor survivin has been implicated in cancer cell survival and disease progression. However, its specific contribution to renal cell carcinoma (RCC) pathogenesis is not well defined. We investigated the roles of survivin in RCC tumor progression, resistance to mTOR inhibitors, and evaluated the therapeutic activity of the survivin suppressant YM155 in RCC models. Here, we report that survivin expression levels were significantly higher in RCC cell lines compared with normal renal cells. Stable targeted knockdown of survivin completely abrogated the ability of 786-O RCC tumors to grow in mice, thus demonstrating its importance as a regulator of RCC tumorigenesis. We next explored multiple strategies to therapeutically inhibit survivin function in RCC. Treatment with the mTOR inhibitor temsirolimus partially diminished survivin levels and this effect was augmented by the addition of YM155. Further analyses revealed that, in accordance with their combined anti-survivin effects, YM155 significantly improved the anticancer activity of temsirolimus in a panel of RCC cell lines in vitro and in xenograft models in vivo. Similar to pharmacologic inhibition of survivin, shRNA-mediated silencing of survivin expression not only inhibited RCC tumor growth, but also significantly sensitized RCC cells to temsirolimus therapy. Subsequent experiments demonstrated that the effectiveness of this dual survivin/mTOR inhibition strategy was mediated by a potent decrease in survivin levels and corresponding induction of apoptosis. Our findings establish survivin inhibition as a novel approach to improve RCC therapy that warrants further investigation.
抗凋亡因子survivin的高表达与癌细胞存活及疾病进展有关。然而,其对肾细胞癌(RCC)发病机制的具体作用尚未明确界定。我们研究了survivin在RCC肿瘤进展、对mTOR抑制剂耐药性中的作用,并评估了survivin抑制剂YM155在RCC模型中的治疗活性。在此,我们报告RCC细胞系中survivin表达水平显著高于正常肾细胞。稳定靶向敲低survivin完全消除了786 - O RCC肿瘤在小鼠体内生长的能力,从而证明其作为RCC肿瘤发生调节因子的重要性。接下来,我们探索了多种在RCC中治疗性抑制survivin功能的策略。用mTOR抑制剂替西罗莫司治疗可部分降低survivin水平,添加YM155可增强此效应。进一步分析表明,根据它们联合的抗survivin作用,YM155在体外一组RCC细胞系和体内异种移植模型中显著提高了替西罗莫司的抗癌活性。与survivin的药物抑制相似,shRNA介导的survivin表达沉默不仅抑制RCC肿瘤生长,还显著使RCC细胞对替西罗莫司治疗敏感。随后的实验表明,这种双survivin/mTOR抑制策略的有效性是由survivin水平的显著降低和相应的凋亡诱导介导的。我们的研究结果确立了抑制survivin作为一种改善RCC治疗的新方法,值得进一步研究。