Fig. 8.

OPN expression controls activation state of ERK1/2 and AKT signaling pathways in CO- and PH-Fibs. A: under serum-free conditions, PH-Fibs exhibited constitutively activated [phosphorylated (p-)] ERK1/2 and AKT signaling pathways (PH-Fibs, NT lane). In contrast, under serum-free conditions, CO-Fibs exhibited low- to not- phosphorylated states of ERK1/2 and AKT, respectively (CO-Fibs, NT lane). Treatment of CO-Fibs with rOPN (20 ng/ml, 6 h) resulted in profound activation (phosphorylation) of both ERK1/2 and AKT signaling pathways (CO-Fibs, rOPN lane). B and C: treatment of PH-Fibs, maintained under serum-free conditions, with OPN-siRNA-3 (50 nM, 72 h) resulted in significant downregulation of both phospho-ERK1/2 (B) and phospho-AKT (C) compared with scrambled oligos (SCR). Data represent mean ± SE from 3 different experiments. **P < 0.01.