Apoptosis independence in VEN-induced phagocytosis. (A) CARNAVAL cells were pretreated with increasing concentrations of the pan caspase inhibitor Z-VAD-FMK for 1 hour before being subjected to 1 µM VEN for 12 hours. Protein levels of cPARP were analyzed by Western blot. (B) Percentages of cells phagocytosed by human macrophages with VEN/antibody combinations compared with VEN, the pan-caspase inhibitor Z-VAD-FMK (Z-VAD) for 1 hour, RTX, or combination of VEN and Z-VAD-FMK (combi). CARNAVAL cells were treated with 50 µM Z-VAD-FMK for 1 hour or/and 1 nM VEN for 12 hours. (C) WILL-2 cells were pretreated with increasing concentrations of the pan caspase inhibitor Z-VAD-FMK/1 hour before subjected to 1 µM VEN for 12 hour. Protein expression of cPARP was analyzed by Western blot. (D) In vitro phagocytosis assays with human macrophages in WILL-2 cells treated with 1 nM VEN for 12 hours or/and 50 µM Z-VAD-FMK for 1 hour alone, the combination (combi), DARA, and the control antibody RTX. Phagocytosis was analyzed as described above. Data are presented as mean ± SEM from independent experiments with 4 healthy blood donors. Tubulin served as a loading control.