Effect of tariquidar on the accumulation of paclitaxel in HEK/pcDNA and HEK/MRP7 cells.

<p>The accumulation of [³H]-paclitaxel was measured after preincubation in the presence or absence of tariquidar at 0.1 µM and 0.3 µM for 2 h (A) or 70 h (B) at 37°C, followed by incubation with 0.1 µM [³H]-paclitaxel with or without of the reversal agents for another 2 h at 37°C. Then, the cells were collected and the intracellular level of [³H]-paclitaxel was detected by scintillation counting. Experiments were done in triplicates, and results were expressed as mean ± SD. *<i>P</i><0.05, versus the respectively untreated controls. Flow cytemetric detection of the amount of intracellular BODIPY-paclitaxel inside HEK/MRP7 cells after treatment with tariquidar for 4 h and 72 h. The histograms represent the fluorescence signal of intracellular BODIPY-paclitaxel in the presence (dashed line) or absence (shaded histogram) of 4 h (C) or 72 h (D) treatment with 0.3 µM tariquidar.