Zerumbone suppressed IKKα phosphorylation in GBM8401 cells . (A) Cells were transiently transfected with pcDNA (control vector), IKKα or IKKβ and HA for 24 h and then were treated with zerumbone (50 μM) for another 24 h before harvesting. Cell viability was then determined by the MTT assay and western blotting. * p < 0.05, compared with the pc DNA-transfected group in the presence of zerumbone. (B) Cells were treated with 50 μM zerumbone for the indicated time intervals. IKKα/βphosphorylation was then determined by immunoblotting. Each column represents the mean ± S.E.M. of at least three independent experiments. *p < 0.05, compared with the control group.