Effect of PLX4032 and PLX4720 on ABCG2 activity. A) Influence of PLX4032 or PLX4720 on BODIPY-prazosine (1 μM) fluorescence in UKF-NB-3ABCG2 cells, B) time kinetics of BODIPY-prazosine (1 μM) fluorescence in UKF-NB-3ABCG2 cells in the presence of PLX4032 or PLX4720 after a 60 min pre-incubation period with subsequent wash-out of extracellular BODIPY-prazosine and PLX4032 or PLX4720 (control = BODIPY-prazosine incubation in the absence of drugs). C) ABCG2 ATPase activity in isolated membranes in the presence of PLX4032 or PLX4720 (control = activity in the absence of drugs). Sulfasalazine, a known ABCG2 substrate, was used for comparison. *P < 0.05 relative to non-treated controls.