Dergi makalesi Açık Erişim

Dual-Inhibition of mTOR and Bcl-2 Enhances the Anti-tumor Effect of Everolimus against Renal Cell Carcinoma In Vitro and In Vivo

2019    Nayman, Ayse Hande; Siginc, Halime; Zemheri, Ebru; Yencilek, Faruk; Yildirim, Asif; Telci, Dilek

Renal cell carcinoma (RCC) is the predominant type of kidney cancer. Mammalian target of rapamycin (mTOR) inhibitor everolimus is currently used as a second-line therapy for sorafenib or sunitinib-refractory metastatic RCC patients. The clinical limitation confronted during everolimus therapy is the onset of drug resistance that decreases the efficacy of the drug. Elevated level of anti-apoptotic Bcl-2 protein is proposed to be an emerging feedback loop for the acquired drug-resistance in various cancer types. In this study, the Bcl-2 inhibitor ABT-737 was used in combination with everolimus to enhance its anti-tumor effectiveness in everolimus-resistant RCC cell lines. Everolimus and ABT-737 combination synergistically led to a decrease in the proliferation of primary site A-498 and metastatic site Caki-1 RCC cell lines, which was accompanied by a reduction in protein levels of cell cycle and mTOR pathway proteins. In both RCC cell lines, everolimus-ABT-737 combination not only induced apoptosis, caspase and PARP-1 cleavage but also a decrease in Bcl-2 protein levels in parallel with a concomitant increase in Bim and Noxa levels.