Figure 8.

The effect of MAPK inhibitors on cPLA₂ activation and COX2 induction. Cells were pre-treated with either 10 μM PD 98059 (PD), 10 μM apigenin (AP) or 10 μM SB 203580 (SB) for 3 h prior to treatment with 10 nM EGF for 30 min or 1 ng ml⁻¹ IL-1β for 3 h. Immunoprecipitates of ERK1 and cPLA₂ were examined for activation status by Western blotting with antibodies to phosphothreonine (PT) and phosphoserine (PS) respectively. COX2 expression was assessed Western blotting the total cell lysate with COX2 antibody. The activation of ERK1 and cPLA₂ by either EGF or IL-1β was prevented by both PD and AP but unaffected by SB. Whereas the induction of COX2 was unaffected by PD and AP but reveresed by SB.