[3H]chloroquine transcellular transport from the basal to the apical compartment by monolayers of MDCK-vector control (Co), MDCK-OCT2 (OCT2), MDCK-MATE1 (MATE1), and MDCK-OCT2-MATE1 (OCT2-MATE1) cells after 30 min. [3H]chloroquine was administered to the basal compartment at 0.1 μM (a), 1 μM (b), 10 μM (c), or 100 μM (d). Data are shown as the mean ± SD. Data were analyzed by one-way ANOVA followed by Tukey-Kramer's posttest. **, P < 0.01 versus MDCK-vector control; ***, P < 0.001 versus MDCK-vector control; ##, P < 0.01 versus MDCK-OCT2; ###, P < 0.001 versus MDCK-OCT2; §, P < 0.05 versus MDCK-MATE1.