Almonertinib inhibits ABCB1-mediated transport of calcein-AM. (A) HEK293 cells transfected with human ABCB1 (MDR19, left panel), (B) ABCB1-overexpressing NCI-ADR-RES cancer cells (left panel), and (C) ABCB1-overexpressing KB-V-1 cancer cells (left panel), as well as in respective parental cells (A-C, right panels). Cells were treated with 0.25 μM calcein-AM and DMSO (A-C, solid line), 20 μM of almonertinib (A-C, filled solid line), or 20 μM of verapamil (A-C, dotted line) as a positive control for ABCB1. Representative histograms of at least three independent experiments are shown. (D) Effect of increasing concentrations (0 – 20 μM) of almonertinib on ABCB1-mediated calcein-AM efflux in MDR19 (open triangles), KB-V-1 (open circles), and NCI-ADR-RES (open squares) cells. Points, mean values from at least three independent experiments; bars; S.D.