Fig. 3

PF induces the proteasomal degradation of cyclin D1 and CDK4. a-d The cells were treated with the indicated concentrations of PF for 24 h. For RT-PCR analysis of the gene expression of cyclin D1 and CDK4, total RNA was prepared after PF treatment for 24 h. GAPDH was used as internal control for RP-PCR. e HCT116 cells were pretreated with MG132 for 2 h, and then co-treated with PF (25 μg/ml) for 3 h (cyclin D1) or 10 h (CDK4). Cell lysates were subjected to SDS-PAGE and the Western blot was performed using antibodies against cyclin D1 and CDK4. Actin was used as internal control for Western blot analysis. *P < 0.05 compared to cell without PF treatment