Renal cell carcinoma (RCC) is common renal malignancy within poor prognosis. TGF-beta-activated kinase 1 (TAK1) plays vital roles in cell survival, apoptosis-resistance and carcinogenesis through regulating nuclear factor-kappa B (NF-kappa B) and other cancer-related pathways. Here we found that TAK1 inhibitors (LYTAK1, 5Z-7-oxozeanol (5Z) and NG-25) suppressed NF-kappa B activation and RCC cell (786-O and A489 lines) survival. TAK1 inhibitors induced apoptotic cytotoxicity against RCC cells, which was largely inhibited by the broad or specific caspase inhibitors. Further, shRNA-mediated partial depletion of TAK1 reduced 786-O cell viability whiling activating apoptosis. Significantly, TAK1 was over-expressed in human RCC tissues, and its level was correlated with phosphorylated NF-kappa B. Finally, kinase inhibition or genetic depletion of TAK1 enhanced the activity of vinblastine sulfate (VLB) in RCC cells. Together, these results suggest that TAK1 may be an important oncogene or an effective target for RCC intervention. (C) 2014 Elsevier Inc. All rights reserved.