Fig. 2.

Uptake of R123 in the presence of Cyclosporin A (CsA), DOX or DOX-TRF by K562 sensitive and resistant (K562/DOX) cells as a function of time (A). The values are the means ± SD of three independent experiments. Additionally, on the basis of fluorescence ratios of R123 transport by the examined cell lines, we calculated P-gp functional activities as the slopes of the obtained curves (B). ∗p < 0.05, significant differences between P-gp functional activity calculated from the influx of R123 or R123 plus CsA and from R123 plus DOX or DOX-TRF after a 20-min period of monitoring the transport of fluorescence probe to the cells. +p < 0.05, significant differences between positive control samples (cells pre-incubated with CsA) and cells treated with DOX or DOX-TRF. #p < 0.05, significant differences between cells treated with free DOX or DOX-TRF