(A) U251 and (B) T98G cells with silencing of eEF-2 kinase by siRNA were transfected with an empty control vector or Bcl-xL-expressing plasmids for 24 h, followed by treatment with the indicated concentrations of TRAIL for another 24h. At the end of treatment, cell lysates were prepared and analyzed for protein levels of Bcl-xL, PARP, and cleaved caspase-8 by Western blot analysis. Apoptosis was determined by flow cytometric analysis of Annexin V staining. (C) U251 and (D) T98G cells were transfected with an empty control vector or a Bcl-xL-expressing plasmids for 24 h, followed by treatment with the indicated concentrations of TRAIL and 0.5 µM of NH125 for another 24 h. At the end of treatment, cell lysates were prepared and analyzed for protein levels of Bcl-xL, PARP, and cleaved caspase-8 by Western blot analysis. Apoptosis was determined by flow cytometric analysis of Annexin V staining. Each point represents mean ± S.D. of triplicate determinations; results shown are the representative of three identical experiments. **p < 0.01, t-test.