Fig. 4.

HB-EGF activates ERK1/2 and AKT signaling pathways in KGN and primary hGL cells. A and B, KGN (A) and primary hGL (B) cells were treated with 5 ng/mL HB-EGF (HB) for 10, 30, and 60 min. The levels of phosphorylated and total forms of ERK1/2 and AKT were determined by western blot. C and D, KGN cells were transfected with 50 nM control siRNA (si-Ctrl), EGFR siRNA (si-EGFR) (C), or HER4 siRNA (si-HER4) (D) for 48 h, and then treated with 5 ng/mL HB-EGF (HB) for 10 min. The levels of phosphorylated and total forms of ERK1/2 and AKT as well as the protein levels of EGFR or HER4 were determined by western blot