Effect of the MEK1/2 inhibitor PD98059 and PKA inhibitor H-89 on GM-CSF–stimulated neutrophil survival.

Human neutrophils were cultured for 20 hours in the presence or absence of GM-CSF (10 ng/mL) with or without (A) PD98059 (50 μM) or (B) H-89 (1 μM). Apoptosis was assessed by AnV binding, as detailed in the “Materials and methods” section. Although H-89 caused a significant inhibition of GM-CSF–mediated neutrophil survival, the magnitude of this effect was substantially less than that observed with LY294002. Data represent values from 6 to 7 independent experiments, each performed in triplicate, together with mean ± SEM values. NS indicates not significant. *P < .05 and **P < .005 compared with control, unless otherwise indicated.