Figure 6

LBH589 activates RAIDD and caspase-2, but not p53. Whether the p53 pathway or caspase-2-related factors contribute to the LBH589-induced cell death was investigated by using ST1 and HuT102 (p53 wild type) cells, and KK1 (p53 mutated) cells. (a, b and e) Cells were treated with either vehicle or the indicated concentrations of LBH589 for 24 h. After cells were harvested, western blotting was performed. (c) Western blotting: tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) (100 ng/ml)-treated Jurkat cells were used as a positive control of typical apoptosis and LBH589 (12 nM)-treated K562 cells were used as a negative control. (d) Activation of RAIDD by LBH589. After cells were treated with either vehicle or 50 nM of LBH589 for 24 h, real-time quantitative RT-PCR for RAIDD was performed. The fold increase in each cell line was obtained by setting the value for the expression without LBH589 as 1.0.