Fig. 3. BEL-induced phosphorylation of p53 is sensitive to caffeine. (A) BEL-induced phosphorylation in HCT116 cells. HCT116 cells were cultured in the presence and absence of 2.5 mM caffeine for 12 hours and continuously cultured in the presence or absence of 12.5 µM BEL for 12 hours. Cell lysates were analyzed for p53-P, p53, p27 and p21 by western blotting. (B) BEL induced p53-P and accumulation of p53 in rat pancreatic -cell line INS-1 cells. INS-1 cells were treated as described in A and cell lysates were analyzed for p53-P, p53, PCNA and actin by western blotting.