3ATA decreases the viability of the B16/F10, a cell line that expresses active MRP1/ABCC1. (A) The effects of 3ATA on the viability of B16F10 cells were assessed by MTT assays as described in the Experimental Section (ES). The results, presented as the percentage of cell viability, represent the mean ± SD of 2 experiments performed in triplicate. (B) The activity of MRP1/ABCC1 in B16/F10 cells was measured using flow cytometry in cells incubated with 5 μM CFDA in the absence (control) or presence of different concentrations of MK-571, a conventional MRP1 inhibitor, as described in ES. The results are presented as arbitrary units (a.u.) of the mean fluoresce intensity from 3 experiments. (C) The expression of MRP1/ABCC1 was evaluated by flow cytometry (top) and western blotting (bottom) as described in ES. (Top) Histogram showing the fluorescence of B16F10 cells treated with medium (AF), PE-labeled secondary antibody (sec) or MRP1/ABCC1 antibody (MRP1). (Bottom) Western blotting analysis of B16F10 cells extract revealed using tubulin and MRP1/ABCC1 antibodies.