Possible involvement of pregnane X receptor–enhanced CYP24 expression in drug-induced osteomalacia
J. Clin. Invest. Jean Marc Pascussi, et al. 115:177 doi:10.1172/JCI21867 [Go to this article.]

Figure 4
Rifampicin induces the CYP24 gene in a Hek293 cell line stably transfected with PXR. (A) Expression of human PXR in parental and pIRES-hPXR/neo–transfected Hek293 cells. Whole-cell extracts were prepared from parental Hek293 cells or pIRES-hPXR/neo–transfected cells (Hek293-hPXR). Proteins were separated on 10% SDS-PAGE, and PXR and β-actin expression was monitored by Western blotting (Santa Cruz Biotechnology Inc.). (B) Rifampicin activates an NR1-LUC reporter gene in Hek293-hPXR cells. Parental Hek293 or Hek293-hPXR cell lines were transiently transfected with CYP2B6 NR1-LUC reporter gene together with pRSV-β-gal transfection control plasmid. After transfection, cells were treated with 0.1% DMSO (UT; white bars) or 10 μM rifampicin (RIF; black bars). Values represent β-gal–corrected luciferase activities normalized to the corresponding level in untreated Hek293 cells and are the average of duplicates ± SE. These were replicated in independent experiments. (C) Rifampicin and hyperforin induce the CYP24 gene in Hek293-hPXR cells. Parental Hek293 or Hek293-hPXR cell lines were untreated (UT) or treated with 50 nM 1α,25(OH)₂D₃ (VD₃), 10 μM rifampicin (RIF), or 2 μM hyperforin (HP) in triplicate. Forty-eight hours later, total RNA was extracted and analyzed by quantitative RT-PCR for CYP24 and GAPDH mRNA content. Values represent the average ± SE.