Figure 2

High-throughput screening demonstrates that substrate specificity of zebrafish Abcb4 closely resembles that of human P-gp. (a) High throughput screening was performed with 90 human P-gp substrates with empty vector transfected cells (Vector) or cells transfected to express zebrafish Abcb4 (Dr Abcb4), zebrafish Abcb5 (Dr Abcb5) or human P-gp (MDR-19). Compound activity was then subjected to unsupervised clustering against Vector, Dr Abcb4, Dr Abcb5 and MDR-19 cells. Darker red color represents greater cytotoxicity. (b) The difference in AUC (delta AUC) was determined as the difference between Vector cells as compared to Dr Abcb4, Dr Abcb5 or MDR-19 cells. The delta AUC values for human P-gp (MDR-19 cells) were compared to those of zebrafish Abcb4 (Dr Abcb4) or zebrafish Abcb5 (Dr Abcb5). Solid lines represent lines of best fit and dashed lines are 95% confidence intervals. (c) Three-day cytotoxicity assays were performed with 6 substrates included in the screen—17-AAG, AT9283, KW-2478, romidepsin, VX-680 and YM-155. Results from all the experiments are summarized in Table S2.