title: Dual effects of ketoconazole cis-enantiomers on CYP3A4 in human hepatocytes and HepG2 Cells.
abstract: Antifungal drug ketoconazole causes severe drug-drug interactions by influencing gene expression and catalytic activity of major drug-metabolizing enzyme cytochrome P450 CYP3A4. Ketoconazole is administered in the form of racemic mixture of two cis-enantiomers, i.e. (+)-ketoconazole and (-)-ketoconazole. Many enantiopure drugs were introduced to human pharmacotherapy in last two decades. In the current paper, we have examined the effects of ketoconazole cis-enantiomers on the expression of CYP3A4 in human hepatocytes and HepG2 cells and on catalytic activity of CYP3A4 in human liver microsomes. We show that both ketoconazole enantiomers induce CYP3A4 mRNA and protein in human hepatocytes and HepG2 cells. Gene reporter assays revealed partial agonist activity of ketoconazole enantiomers towards pregnane X receptor PXR. Catalytic activity of CYP3A4/5 towards two prototypic substrates of CYP3A enzymes, testosterone and midazolam, was determined in presence of both (+)-ketoconazole and (-)-ketoconazole in human liver microsomes. Overall, both ketoconazole cis-enantiomers induced CYP3A4 in human cells and inhibited CYP3A4 in human liver microsomes. While interaction of ketoconazole with PXR and induction of CYP3A4 did not display enantiospecific pattern, inhibition of CYP3A4 catalytic activity by ketoconazole differed for ketoconazole cis-enantiomers ((+)-ketoconazole IC₅₀ 1.69 µM, Ki 0.92 µM for testosterone, IC₅₀ 1.46 µM, Ki 2.52 µM for midazolam; (-)-ketoconazole IC₅₀ 0.90 µM, Ki 0.17 µM for testosterone, IC₅₀ 1.04 µM, Ki 1.51 µM for midazolam).
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Olomouc, Czech Republic.
authors.forename: Aneta
authors.initials: A
authors.lastname: Novotná
authors.affiliation: Institute of Pharmacology, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic.
authors.forename: Kristýna
authors.initials: K
authors.lastname: Krasulová
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Olomouc, Czech Republic.
authors.forename: Iveta
authors.initials: I
authors.lastname: Bartoňková
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Olomouc, Czech Republic.
authors.forename: Martina
authors.initials: M
authors.lastname: Korhoňová
authors.affiliation: 2nd Department of Surgery, University Hospital Olomouc, Olomouc, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Bachleda
authors.affiliation: Institute of Pharmacology, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Anzenbacher
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Olomouc, Czech Republic.
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Dvořák
mesh_terms: D055162:Biocatalysis / Q000187:drug effects; D051544:Cytochrome P-450 CYP3A / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D017930:Genes, Reporter; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D007654:Ketoconazole / Q000737:chemistry* / Q000494:pharmacology*; D007700:Kinetics; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D000077297:Pregnane X Receptor; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism; D013237:Stereoisomerism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000077297:Pregnane X Receptor; D012333:RNA, Messenger; D011987:Receptors, Steroid; D051544:Cytochrome P-450 CYP3A; D007654:Ketoconazole