Fig. 1
BAY-1082439 reversed MDR of cancers via down-regulating P-gp and BCRP transporters. a MTT assay showing the ability of BAY-1082439 to reverse MDR mediated by P-gp over-expressed in KB-C2 cells and BCRP over-expressed in H460/MX20 cells. Viability of cells without treatment with BAY-1082439 and anti-cancer drugs (colchicine for KB-C2 and mitoxantrone for H460/MX20) was set as standard control (denominator) for comparing the combined effect of BAY-1082439. The negative control, parental drug-sensitive cells KB-3-1 and H460 were treated through the same procedure. IC50 are indicated by arrows. b Down-regulation of P-gp and BCRP by BAY-1082439 targeting PI3K 110α and 110β. The cells were cultured with drugs and BAY-1082439 (BAY, 10 μM), and analyzed by Western blot. Relative quantification was carried out with ImageQuant TL based on the intensity of the bands. Colchicine at 0.7 and 0.01 μM were applied to drug-resistant KB-C2 and drug-sensitive KB-3-1 cells, respectively. Mitoxantrone at 3 and 0.3 μM were applied to drug-resistant H460/MX20 and drug-sensitive H460 cells, respectively. c Localization and level of P-gp and BCRP in the MDR cancer cells determined by immuno-fluorescence (IF). Positive signals on cell membrane and nuclear envelope are depicted by orange and purple arrows, respectively. Inhibition of P-gp and BCRP by BAY-1082439 is depicted by arrows in light blue. KB-C2 and H460/MX80 cells were cultured with 1 μM of colchicine and mitoxantrone, respectively, followed by co-culture with 10 μM of BAY-1082439. By 24 h and 48 h of co-culture, respectively, KB-C2 and H460/MX80 cells showing inhibition of P-gp or BCRP expression were studied by IF analysis