title: Evaluation of the Interplay between Uptake Transport and CYP3A4 Induction in Micropatterned Cocultured Hepatocytes.
abstract: Previously we assessed the inductive response of prototypical inducers in hepatocyte monocultures and the long-term coculture model HepatoPac using cryopreserved hepatocytes from the same donors. We noted that the rifampicin EC50generated using the HepatoPac model corresponded better to the EC50based on clinical data compared with data generated in the monoculture system. We postulated that there may be differences in the functioning of uptake transporters between the two systems that may have led to the EC50difference. In this study, we characterized the functional activity of multiple uptake transporters in the two systems using cryopreserved hepatocytes from the same donors. Our data suggest that uptake transporter activity is higher in HepatoPac compared with the monoculture system. As a follow up to this study, we measured the intracellular concentrations of rifampicin and bosentan, which are known substrates of uptake transporters; we observed significantly higher intracellular concentrations of both compounds in HepatoPac relative to the monoculture system. This finding equated to lower cytochrome P450 isoform 3A4 (CYP3A4) EC50values in the HepatoPac system compared with the monoculture system for both mRNA and activity. In parallel, no significant EC50shift was observed for carbamazepine and phenytoin, which are not known to be substrates of uptake transporters. Our data suggest that next generation liver models such as HepatoPac may be a useful in vitro tool to quantitatively predict drug-drug interactions when it is known that the perpetrator is also a substrate of drug transporters.
authors.affiliation: Drug Metabolism and Pharmacokinetics, Vertex Pharmaceuticals Incorporated, Boston, Massachusetts.
authors.forename: Amanda
authors.initials: A
authors.lastname: Moore
authors.affiliation: Drug Metabolism and Pharmacokinetics, Vertex Pharmaceuticals Incorporated, Boston, Massachusetts.
authors.forename: Paresh P
authors.initials: PP
authors.lastname: Chothe
authors.affiliation: Drug Metabolism and Pharmacokinetics, Vertex Pharmaceuticals Incorporated, Boston, Massachusetts.
authors.forename: Hong
authors.initials: H
authors.lastname: Tsao
authors.affiliation: Drug Metabolism and Pharmacokinetics, Vertex Pharmaceuticals Incorporated, Boston, Massachusetts niresh_hariparsad@vrtx.com.
authors.forename: Niresh
authors.initials: N
authors.lastname: Hariparsad
mesh_terms: D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D018920:Coculture Techniques / Q000379:methods; D015925:Cryopreservation / Q000379:methods; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism*; D065701:Cytochrome P-450 CYP3A Inducers / Q000494:pharmacology; D004347:Drug Interactions / Q000502:physiology; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012293:Rifampin / Q000494:pharmacology
chemical_list: D065701:Cytochrome P-450 CYP3A Inducers; D012333:RNA, Messenger; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D012293:Rifampin