In vitro colony assays for AML and normal cells treated with PTL and Ara-C. AML versus normal cells in panels A and B were treated with 5 μM (▦) or 7.5 μM PTL (▨). AML versus normal cells in panels C and D were treated with 5 μM Ara-C (▪). All treatments were performed for 18 hours in suspension culture, followed by plating in methylcellulose culture. Error bars represent the SD. Average percent of colony-forming units (CFU) are normalized to untreated control (horizontal bar). All assays were performed in triplicate. Mye represents myeloid; Ery, erythroid.