The effect of vardenafil and tadalafil on the reversal of ABCB1-mediated resistance to vincristine, paclitaxel and cisplatin in ABCB1 transfected cell line.

Cell survival was determined by MTT assay as described in “Materials and Methods”. Data are expressed as the means ± SD of at least three independent experiments performed in triplicate. The fold-The magnitude of the MDR fold reversalreversal of MDR ((values given in parentheses) was calculated by dividing the IC50 for cells with the anticancer drug in the absence of inhibitor by that obtained in the presence of inhibitor.
**represents P<0.01,
*represents P<0.05, for values versus that obtained in the absence of inhibitor.