Normal (MCF12A) and cancer (HeLa MR and U251) cells exhibit very different caspase cleavage activity after MNNG exposure.

<p>Pan-caspase cleavage detection (ApoStat Apoptosis Detection Kit; R&D Systems) using flow cytometric analysis of a pan-caspase inhibitor can detect total percent of the population containing caspase cleavage products. Both MCF12A and HeLa MR have detectable amounts from 24-72 hr, but not U251 cells after MNNG treatment (<10%) up to 72 hr later. As positive control, caspase cleavage is detected in all cell lines within 3 hr after staurosporine (Strsp) treatment. Each assay was performed a minimum of two times.