C5 enhances tumor-cell sensitivity to apoptotic stimuli.

M14 or M14TF4 cells (1 × 10⁶/mL) were exposed to 150 μg/mL C5 for 2 hours and then by 8-hour incubation with 40 μmol/L etoposide or 10 ng/mL rTNF-αb, respectively, in the presence or absence of DEVD (1 μmol/L). Lysates were then analyzed for caspase 3 activity, as described in “Materials and methods.” Data are shown as fold increase (x increase) in activity over the untreated control cells (1 × ).