Figure 2: Concentration dependency of IGF1 and α-IR3 on Apo2L/TRAIL-induced apoptosis. Percentage-specific apoptosis in VH-64 cells treated for (a) 24 hours and (b) 72 hours with the indicated concentrations of IGF1 and α-IR3, followed by incubation with Apo2L/TRAIL (50 ng/mL; 8 hours). All incubations contained nonspecific isotype IgG at a final concentration of 3 μg/mL. Asterisks: * ; error bars: mean ± SD of triplicate determinations from 3 independent experiments.