Figure 5.

c-fos is involved in the upregulation of p21^Cip1/WAF1 induced by lauric acid. Immunoblots of c-fos and p21^Cip1/WAF1 (p21) in SkBr3 (a) and Ishikawa (b) cells treated for 4 h with vehicle (−) or 100 μM LA alone or in combination with 300 μM free radical scavenger NAC, 10 μM EGFR inhibitor AG1478 (AG), 10 μM MEK inhibitor PD98089 (PD), 1 μM JNK inhibitor SP 600125 (SP) and 10 μM ROCK inhibitor Y-27632 (Y). The expression vector encoding for a dominant-negative form of c-fos (DN/c-fos) blocked the upregulation of p21^Cip1/WAF1 protein levels induced by 100 μM LA in SkBr3 (c) and Ishikawa (d) cells. β-actin was used as a loading control. Results shown are representative of at least two independent experiments. (e) Recruitment of c-fos induced by 100 μM LA to the AP1 site located within the p21^Cip1/WAF1 promoter sequence in SkBr3 and Ishikawa cells, as indicated. In control samples non-specific IgG was used instead of the primary antibody. Each column represents the mean±S.D. of three independent experiments. (○) indicates P<0.05 for cells receiving vehicle versus treatments.