FIG. 2.

Susceptibility to DR5-induced cell death and activation of caspase 3. (A) U87-MG (▪) and CRT-MG (▴) cells were incubated with various concentrations of anti-DR5 antibody TRA-8 (0 to 1,000 ng/ml) or hrTRAIL (0 to 200 ng/ml) for 24 h, and then cell death was measured by staining with Annexin V-FITC and PI. Data are the mean and SD for duplicate samples from one experiment and are representative of three independent experiments. (B) Cells were incubated with TRA-8 (100 ng/ml) in complete medium for various times (0 to 24 h), and caspase 3 activity was measured as indicated in Materials and Methods. The relative fluorescence of each sample was normalized to the amount of total protein. Data are the mean and SD for quadruplicate samples from one experiment and are representative of two independent experiments.