Apoptotic cells attenuate caspase-3 activation in murine and human macrophages. Caspase-3 activity in (A) murine RAW 264.7 macrophages and (B) human monocyte-derived THP-1 macrophages normalized to untreated control cells. Macrophages were pretreated with AC, NC, or VC or remained as controls for 16 hours. Cell death was induced for 8 hours with 250 μM etoposide. Data are presented as the mean ± SD from 3 independent experiments. Differences between untreated and AC-treated cells are statistically significant and marked with an asterisk (P < .05). (C) Apoptosis in Jurkat cells induced with 0.5 μg/mL staurosporine followed by annexin V/PI staining after 1, 3, and 6 hours. Parameters were assessed by flow cytometry.