Fig. 3.

Intracellular R123 accumulation in K562 cells sensitive and resistant (K562/DOX) to doxorubicin. The cells were incubated with IC₅₀ concentrations of free DOX or DOX-TRF for 24 h. In the experiments with Cyclosporin A (CsA) the cells were preincubated for 20 min at 37 °C and then incubated with drugs. Fluorescence was monitored using an Olympus IX70 microscope (Japan), magnification 400×