Fig. 4.

CK2α knockdown, inhibition of CK2, and mutation of the putative CK2 phosphorylation site at Thr249 to alanine results in decreased MRP1-mediated doxorubicin efflux. Doxorubicin accumulation assays were performed as described under Materials and Methods. Where indicated, cells were pretreated with 10 μM DMAT, a potent CK2α inhibitor, before the addition of doxorubicin (gray bars). The bars represent mean value ± S.D. of three or more separate experiments with treatments performed in triplicate or greater. Statistical analysis was performed using ANOVA followed by Bonferroni post test.