PAF activates ERK1/2 signaling via both EGFR-dependent and EGFR-independent pathways. (A) SKOV-3 cells were treated with 100 nM PAF for 0, 5, 10, 15, or 20 min. Following PAF treatment, the cells were lysed, and the lysates were evaluated by Western blotting. Data were normalized to total ERK protein expression and are expressed as fold-change (average ± S.E.M.) in phospho-ERK compared to vehicle-treated cells. Representative blots for phosphor/total-ERK are shown. (B) SKOV-3 cells were treated with AG1478 (20 μM) for 1 hour before stimulation with PAF (100 nM) or EGF (5 ng/ml) for 5 min. Cells were harvested and subjected to Western blot. (C) SKOV-3 cells were pretreated for 1 h with increasing concentrations of the EGFR inhibitor AG1478. Cells were then stimulated with PAF (100 nM) for 5 min before they were harvested and subjected to Western blot. The data shown are representative of at least three independent experiments. Data were analyzed by Student’st-test. * p < 0.05.