A. Effect of HGF on proliferation of ARPE-19. After serum starvation for 24 hours, HGF at 0.01, 0.1, 1, 10, 50 ng/ml
concentrations were added and incubation was done for 48 hours under serum-free conditions. HGF stimulated ARPE-19 cell proliferation in a dose-dependent manner. (n=9, S.D. 3.7%, p<0.01) B. Inhibition of ARPE-19 cell proliferation with neutralizing the HGF receptor/c-Met. To investigate the relationship between the induction of c-met, HGF expression and serum-starved ARPE-19 proliferation, we performed a colorimetric procedure to the known MTS proliferation assay. Neutralized ARPE-19 cells with anti-c-met antibody (2 µg/ml) inhibited cell proliferation up to 55%. A and B data are presented as means±S.D, n=9. C and D. Down regulation of HGF/c-Met in ARPE-19 cells with neutralizing c-Met antibody. After neutralization, HGF was down-regulated at the transcriptional level (C), but c-Met was at translational level (D). C; normal ARPE-19 as a control, S; after serum starvation for 24 hours, PBS was added for 2 days as a control of mAb, S+mAb; after serum starvation for 24 hours, neutralization was performed using monoclonal anti-mouse c-Met
antibody (mAb) for 2 days.