Fig. 1. A, effect of MEK inhibitors PD 98059 (20 µM) and U0126 (15 µM) on bryo 1-induced cell growth inhibition. B, Reh cell differentiation. Reh cells were treated with bryo 1, the MEK inhibitor PD 98059, or the combination of bryo 1 and PD 98059 for 24 h. Bryo 1-induced cellular differentiation was reduced significantly when cells were pretreated for 30 min with PD 98059 as shown by cellular adhesion and surface expression of CD11c.