Fig. 1.

A, effect of azole compounds on the LanthaScreen TR-FRET PXR (SXR) competitive binding assay in vitro. Rifampicin was included as a positive control PXR ligand. B and C, effect of FLB-12 (Cpd3) on hPXR and hPXR triple mutant (S247W/S208W/C284W) activity. Transactivation assays were performed using plasmids encoding hPXR (B) or triple-mutant hPXR (C) with respective reporters/ligands, as shown in the schematic diagram. Transfected cells were exposed to vehicle (0.2% DMSO), 10 μM Rif, with or without 25 μM FLB-12. Columns, mean; bars, S.E.M.; *, P < 0.0048; **, P < 0.0280. D, effect of FLB-12 on PXR target gene expression. RT-qPCR for human PXR and target genes (CYP3A4, MDR1, and UGT1A1) was carried out in LS174T cells exposed to 10 μM Rif with or without 25 μM FLB-12 or KTZ or vehicle (0.2% DMSO) for 48 h. Total RNA was isolated and subjected to RT-qPCR. β-Actin served as an internal control. These experiments were performed two separate times each, assayed in triplicate. Columns, bars, S.D.