Effect of MIP-1α on MEK/MAPK signaling pathways in MM cells.

(A) MM1.S cells and (B) pat MM cells were stimulated with MIP-1α (100 ng/mL) for 5 and 15 minutes. Pretreatment with 1 μM PI3-kinase inhibitor wortmannin or MEK1 inhibitor PD 98059 (50 μM) was performed for 1 hour prior to cytokine treatment. Cells were lysed, electrophoresed, and immunoblotted with antiphospho-ERK1,2 ab. β-Actin antibody served as loading control. (C) MM1.S cells were pretreated with MEK1 inhibitor PD 98059 (50 μM, 1 hour) and/or PI3-K inhibitor LY 294002 (50 μM, 1 hour), stimulated with MIP-K (100 ng/mL, 15 minutes), and subjected to Western blotting using antiphospho-AKT (Ser473) (upper blot) or antiphospho-ERK1,2 antibody (middle panel). β-Actin antibody served as loading control (ctr; lower blot).