Akt in zerumbone-induced GBM cell apoptosis . (A) Cells were transfected with empty vector (mock) or wild-type Akt (WT-Akt) for 24 h. Following transfection, cells were treated with vehicle or 50 μM zerumbone for 24 h. Cell viability was then determined by the MTT assay and immunoblotting. Under overexpression of Akt, the phosphorylation level of Akt also increased compared to the mock group, suggesting Akt is functional in GBM8401 cells. Each column represents the mean ± S.E.M. of at least 3 independent experiments. *p < 0.05, compared with the group with trasfected with the empty vector, in the presence of zerumbone. (B) Cells were treated with vehicle or zerumbone (50 μM) for indicated time intervals. Phosphorylation status of Akt was then determined by immunoblotting. Each of the columns represents the mean ± S.E.M. of at least three independent experiments. * p < 0.05, compared with the control group.