Effect of Pgp and BCRP expression on AMG 330-induced cytotoxicity. Parental (A) HL-60, (B) ML-1, and (C) NB4 cells and sublines that were transduced with either wild-type Pgp or BCRP at a MOI of 100 were incubated with increasing concentrations of GO or mitoxantrone without healthy donor T cells or AMG 330 and various E:T cell ratios using healthy donor T cells as indicated. After 48 hours, cell counts were determined and cytotoxicity was assessed with DAPI staining to quantify drug-specific cytotoxicity. Results are shown as mean ± SEM from 3 independent experiments (except 2 independent experiments in the case of AMG 330 cytotoxicity assays in ML-1 cells) performed in duplicate wells using a single healthy donor as source for exogenous T cells.