PB induces P450 expression in HepaRG cells independent of CAR. (A) Schematic illustration of TGGCCAGTAGG deletion and primer localization for DNA genotyping of hCAR-KO HepaRG. After 21 days of differentiation, genomic DNA and cell homogenate prepared from both WT- and hCAR-KO HepaRG cells were subjected to PCR (B) and western blotting analysis (C). Differentiated WT- and hCAR-KO HepaRG cells were treated with 1 mM PB, 10 µM RIF, or 1 µM CITCO for 24 or 72 hours to measure CYP2B6 and CYP3A4 mRNA (D, E, G, and H) or protein expressions (F and I) using RT-PCR and western blotting assay, respectively. Results are expressed as mean ± S.D. (n = 3) (*P < 0.05; ***P < 0.001).