Model-estimated fold change and associated SE of the accumulation of [3H]-E217βG (1 µM, 2 min) (A) and [3H]-CCK-8 (1 µM, 3 min) (B) in HEK293-OATP1B1 and HEK293-OATP1B3 cells, respectively. The cells were pre-incubated with vehicle CTL-, 0.2 µM EVR-, or 0.5 µM SIR-containing culture medium for 1 hour either alone or in combination with 10 µM INK-128, following an earlier 1-hour treatment with 10 µM INK-128 alone. At the end of pre-incubation, the culture medium was removed and substrate accumulation was determined (n=3 in triplicate) in the absence of inhibitors after washing. Fold changes and SE were estimated using a generalized linear mixed model, as described in the “Materials and Methods”. * indicates a statistically significant difference (p<0.05) vs. CTL.