Figure 6

Inhibition of certain mitogen-activated protein kinases (MAPKs) up-regulates the activity of -575 p27 (5'-untranslated region (5'UTR) of p27 gene). All four types of cells were transfected with -575 p27 (p27-5'UTR) and then exposed to the following inhibitors: PD98059 (1.87 μM) to inhibit MEK; ERK activation inhibitor peptide I (0.80 μM) and ERK activation inhibitor peptide II (1.42 μM) to inhibit ERK; PD169316 (1.39 μM), SB203580 (1.33 μM), SB202190 (1.51 μM), and SB202474 (1.79 μM) to inhibit p38MAPK; anisomycin (1.89 μM) to activate MAPKs and stress-activated proteins kinases (SAPKs); Ro-32-0432 (1.02 μM) to inhibit protein kinase C (PKC); and hypericin (0.99 μM) to inhibit PKC/ERK. All assays were performed in triplicates and the transfection experiments were repeated three times.