Development of in vitro methods to predict induction of CYP1A2 and CYP3A4 in humans.
The important role of cytochrome P450 (CYP) drug-metabolizing enzymes has been studied for many years, and the potential liabilities of inducing these enzymes are well understood. Though several mechanisms of induction have been studied, a growing consensus is developing that the aryl hydrocarbon receptor (AHR) and the pregnane X receptor (PXR) have evolved as the primary mechanisms responsible for clinically relevant drug-drug interactions caused by induction of drug-metabolizing factors. AHR and PXR have been identified as inducers of a variety of Phase I and Phase II drug-metabolizing enzymes, drug transporters, and other factors involved in drug metabolism. Though many genes are induced through these regulating factors, CYP1A2 and CYP3A4 have been the most reliable biomarkers to identify compounds with potential induction liabilities through AHR and PXR, respectively. Here are presented several in vitro methods to detect AHR- and PXR-mediated induction of CYP1A2 and CYP3A4 in fresh and cryopreserved primary human hepatocytes, stable transfectants, and transiently transfected immortalized cells.
Pharmacokinetics, Dynamics & Metabolism, Pfizer Global Research and Development, Ann Arbor, MI, USA. scott.grover@pfizer.com
G Scott
GS
Grover
Timothy G
TG
Brayman
Richard L
RL
Voorman
Joseph A
JA
Ware
D002469:Cell Separation; D002470:Cell Survival; D002478:Cells, Cultured; D015925:Cryopreservation; D019388:Cytochrome P-450 CYP1A2 / Q000096:biosynthesis* / Q000235:genetics; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction / Q000187:drug effects; D017930:Genes, Reporter / Q000187:drug effects / Q000235:genetics; D022781:Hepatocytes / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D000077297:Pregnane X Receptor; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D018336:Receptors, Aryl Hydrocarbon / Q000187:drug effects / Q000235:genetics; D011987:Receptors, Steroid / Q000187:drug effects / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000077297:Pregnane X Receptor; D018336:Receptors, Aryl Hydrocarbon; D011987:Receptors, Steroid; D012313:RNA; D003577:Cytochrome P-450 Enzyme System; C504573:CYP1A2 protein, human; D019388:Cytochrome P-450 CYP1A2; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human