The expression levels of p53 and Bax after TPA (100 nM) treatment in JB6 promotable (P+) and non-promotable (P-) cells.

TPA induced p53 activation and apoptosis only in P+ cells, not P- cells. Total cell lysate was used for the assay. The cells were grown in EMEM medium supplemented with 4% fetal bovine serum, 2 mM of L-glutamine, 50 µg/ml penicillin and 50 µg/ml streptomycin. 12-O-tetradecanoylphorbol-13-actetate (TPA) was prepared as a 20 nM stock solution in dimethylsulfoxide (DMSO). The TPA stock solution was diluted directly in the cell culture medium, with the resulting concentration being 100 nM. Ctrl: vehicle (0.1% DMSO) treatment for 24 h. *, p<0.05 when compared with the Ctrl group.