Fig. 5From: Anti-cancer activity of Psoralea fructus through the downregulation of cyclin D1 and CDK4 in human colorectal cancer cellsDetermination of upstream kinases involved in the proteasomal degradation of cyclin D1 and CDK4 by PF. a HCT116 cells were pretreated with PD98059 (ERK1/2 inhibitor, 20 μM), SB203580 (p38 inhibitor, 20 μM), SP600125 (JNK inhibitor, 20 μM) or LiCl (GSK3β inhibitor, 20 mM) for 2 h, and then co-treated with PF (25 μg/ml) for 3 h (cyclin D1) or 10 h (CDK4). b HCT116 cells were treated with PF (25 μg/ml) for the indicated times. c HCT116 cells were pretreated with PD98059 (ERK1/2 inhibitor, 20 μM) or LiCl (GSK3β inhibitor, 20 mM) for 2 h, and then co-treated with PF (25 μg/ml) for 1 h. Cell lysates were subjected to SDS-PAGE and the Western blot was performed using antibodies against cyclin D1, CDK4, p-ERK1/2, total-ERK1/2, p-GSK3β, total-GSK3β or p-cyclin D1 (Thr286). Actin was used as internal control for Western blot analysis. *P < 0.05 compared to cell without PF treatmentBack to article page