The Anti-renal Cell Carcinoma (RCC) Activity By A Novel Mammalian Target Of Rapamycin (mTOR) Kinase Inhibitor WYE-687

Objective: We here tested the potential anti-renal cell carcinoma(RCC)activity by a novel mammalian target of rapamycin(mTOR)kinase inhibitor WYE-687 in vitro and in vivo.Methods:(1)MTT assay and colony formation assay were performed to test the potential role of WYE-687 on RCC cell survival.(2)Caspase-3 activity assay,Annexin V-PI FACS assay and Western Blotting assay were performed to test RCC cell apoptosis following WYE-687 treatment.(3)BrdU ELISA assay and [H3] Thymidine incorporation assay were performed to examine cell proliferation in WYE-687-treated RCC cells.(4)Western Blotting assay was performed to test mTOR signaling changes in WYE-687-treated RCC cells.(5)786-O xenograft nude mice model was applied,the in vivo anti-RCC cell activity by WYE-687 was analyzed.Results:(1)WYE-687 was cytotoxic and anti-proliferative to established RCC cell lines(786-O and A498)and primary human RCC cells.Yet,it was non-cytotoxic to HK-2 tubular epithelial cells.(2)WYE-687 provoked caspase-dependent apoptosis in the RCC cells.(3)WYE-687 almost completely blocked mTORC1(p-S6K1 and p-S6)and mTORC2(p-Akt Ser 473)activation in both 786-O cells and primary human RCC cells,where it downregulated both hypoxia-inducible factor(HIF)-1α and HIF-2α expression.(4)Significantly,oral administration of WYE-687 potently suppressed 786-O tumor xenograft growth in nude mice.(5)mTORC1/2 activation and HIF-1α/2α expression were also remarkably downregulated in WYE-687-treated tumor tissues.Conclusions:Concurrent inhibition of mTORC1 and mTORC2 by WYE-687 inhibits renal cell carcinoma cell growth in vitro and in vivo...