RGDS treatment activates caspase-3. A: SK-MEL-110 seeded on collagen-IV were incubated for 48 h with FGF-2 in the presence or in the absence of RGDS or RGES (500 μg/ml). Top: Pro-caspase 3 cleavage and caspase-3 activation were observed by western blotting. Bottom: caspase-3 activation was confirmed by confocal microscopy using an anti-active caspase-3 antibody. B: Pre-treatment (2 h) of melanoma cells with Z-VAD-FMK (50 μM), a general caspases inhibitor, abolished the RGDS anti-proliferative effect (p < 0.005 vs FGF-2 in the presence of Z-VAD-FMK). All these experiments were carried out three times in duplicate.