Fig. 7

Multidrug Resistance Direct Dye Efflux Activity in CIPp and CIPm. Cells were loaded with DiOC2(3) and incubated at 4 °C, or at 37 °C in the presence or absence of Vinblastine for 15 min, 1, 4 and 24 h. After washing and PI staining, cells were analyzed by flow cytometry and dead cells were excluded from analysis. Cells incubated at 4 °C (negative control - N) exhibit high fluorescence, as P-gp and BCRP are inactive at low temperatures and the cells retain the dye. Cells incubated at 37 °C (positive control - P) have a progressively lower fluorescence over time, as P-gp and BCRP are active and cells efflux the dye. Cells incubated at 37 °C in the presence of Vinblastine (V) that specifically effluxes via P-gp, have higher fluorescence compared to control cells, as Vinblastine competes with the dye for efflux by P-gp