INK128 induces cell-cycle arrest and apoptosis in MM cells. (A) MM1S and OPM2 cells were cultured with rapamycin (10 and 25nM) or INK128 (10 and 25nM) for 24 hours, and cell-cycle analysis was performed by propidium iodide staining. (B) MM1S and OPM2 cells were treated with rapamycin (5-100nM) or INK128 (5-100nM) for 48 hours, and apoptosis was determined using annexin/propidium iodide staining and flow cytometric analysis. (C) MM1S and OPM2 cells were cultured with rapamycin (25 and 50nM) or INK128 (25 and 50nM) for 24 hours. Whole-cell lysates were subjected to Western blotting using anti–caspase-9, anti–caspase-8, anti–caspase-3, anti-PARP, and anti–α-tubulin Abs.