Table 3. Confirmation of IC₅₀ Values of Compounds 15, 18, 21, 22, and 26^a.

^aHoechst 33342 and daunorubicin assays were conducted using either ABCB1-overexpressing A2780/ADR, ABCC1-overexpressing H69AR, or ABCG2-overexpressing MDCK II BCRP cells as reported earlier.^15,17,57 Cyclosporine A (10 μM; ABCB1 and ABCC1) and compound 34 (10 μM; ABCG2) were used as a reference for 100% inhibition, and buffer medium represented 0%. Shown is the mean ± SEM of at least three independent experiments.