Inhibition of CYP3A4 expression by ketoconazole is mediated by the disruption of pregnane X receptor, steroid receptor coactivator-1, and hepatocyte nuclear factor 4alpha interaction

Pharmacogenet Genomics. 2009 Jan;19(1):11-24. doi: 10.1097/FPC.0b013e32831665ea.

Abstract

Background: Earlier studies have shown that ketoconazole inhibits CYP3A4 expression through pregnane X receptor (PXR)-mediated transcription and coactivator interaction. The involvement of other nuclear receptors remains to be elucidated. It was recently reported that hepatocyte nuclear receptor 4alpha (HNF4alpha), a master regulator of several nuclear receptors, associates with PXR thus regulates the expression of CYP3A4 under rifampin treatment. We therefore focused on the role of PXR-HNF4alpha interaction in the transcriptional regulation of CYP3A4 under rifampin-mediated ketoconazole inhibition.

Methods and results: Several approaches were used to characterize this role and to investigate the relation between the regulatory function of the PXR-HNF4alpha complex and CYP3A4 expression, including a mammalian two-hybrid system, DNA affinity precipitation assay, co-immunoprecipitation, and HNF4alpha silencing by RNA interference. Here, we report that HNF4alpha plays a critical role in CYP3A4 promoter activation, and the interaction between PXR and HNF4alpha, which is closely related to the expression of CYP3A4, might be involved in ketoconazole-mediated inhibition of CYP3A4 gene expression. These observations indicate that the inhibition of the interaction of PXR with HNF4alpha is likely an important mechanism of drug-drug interaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antifungal Agents / pharmacology
  • Base Sequence
  • Cell Line
  • Cytochrome P-450 CYP3A / genetics*
  • Cytochrome P-450 CYP3A Inhibitors*
  • DNA Primers / genetics
  • Gene Expression Regulation, Enzymologic / drug effects
  • HeLa Cells
  • Hepatocyte Nuclear Factor 4 / antagonists & inhibitors*
  • Hepatocyte Nuclear Factor 4 / genetics
  • Hepatocyte Nuclear Factor 4 / metabolism
  • Histone Acetyltransferases / antagonists & inhibitors*
  • Histone Acetyltransferases / metabolism
  • Humans
  • In Vitro Techniques
  • Ketoconazole / pharmacology*
  • Ligands
  • Nuclear Receptor Coactivator 1
  • Pharmacogenetics
  • Pregnane X Receptor
  • Promoter Regions, Genetic
  • Protein Interaction Domains and Motifs
  • RNA Interference
  • Receptors, Steroid / antagonists & inhibitors*
  • Receptors, Steroid / metabolism
  • Recombinant Proteins / antagonists & inhibitors
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Rifampin / pharmacology
  • Transcription Factors / antagonists & inhibitors*
  • Transcription Factors / metabolism
  • Two-Hybrid System Techniques

Substances

  • Antifungal Agents
  • Cytochrome P-450 CYP3A Inhibitors
  • DNA Primers
  • HNF4A protein, human
  • Hepatocyte Nuclear Factor 4
  • Ligands
  • Pregnane X Receptor
  • Receptors, Steroid
  • Recombinant Proteins
  • Transcription Factors
  • Cytochrome P-450 CYP3A
  • CYP3A4 protein, human
  • Histone Acetyltransferases
  • NCOA1 protein, human
  • Nuclear Receptor Coactivator 1
  • Ketoconazole
  • Rifampin