IGF-I activated Akt/ERK downstream signaling pathways and induced EMT in gastric cancer cells. (A) The serum-starved MGC-803 and SGC-7901 cells were incubated with IGF-I (100 ng/mL) for the indicated times, the phosphorylation of IGF-IR, ERK and Akt were analyzed by Western blot. (B-D) The serum-starved cells were pretreated with or without OSI-906 (10 μM), PD98059 (20 μM) or LY294002 (100 μM) for 2 h followed by IGF-I (100 ng/mL) stimulation for 48 h. Cell lysates were collected for Western blot analysis. Photos were taken at × 20 magnification. E-cad, E-cadherin; OSI, OSI-906; PD, PD98059; LY, LY294002.