R-etodolac induces caspase cleavage and activation of apoptosis. MM.1S cells were cultured (A) for 24 hours with R-etodolac (0-1.25 mM) or (B) with R-etodolac (0.6 mM) for the indicated times. CL indicates cleaved band. (C) MM.1S cells were preincubated with Z-VAD-FMK (25 μM) for 30 minutes prior to treatment with R-etodolac (0.6 mM) for the indicated times. (D) RPMI8226 cells were also cultured with or without R-etodolac (0.6 mM) for indicated times. Total cell lysates were subjected to Western blotting using anti-caspase-8, -caspase-9, and -caspase-3, -PARP, and -α-tubulin Abs.