Cytochrome P450 1A2 Messenger RNA is a More Reliable Marker than Cytochrome P450 1A2 Activity, Phenacetin O-Deethylation, for Assessment of Induction Potential of Drug-Metabolizing Enzymes Using HepaRG Cells

Author(s): Akira Ogasawara* , Nozomu Kato , Nao Torimoto , Fumika Aohara , Rikiya Ohashi , Yasuhiro Yamada , Hideki Taniguchi .

Journal Name: Drug Metabolism Letters

Volume 12 , Issue 1 , 2018

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Abstract:

Background: The HepaRG cells have key drug metabolism functionalities comparable to those of primary human hepatocytes. Many studies have reported that this cell line can be used as a reliable in vitro model for human drug metabolism studies, including the assessment of cytochrome P450 (CYP) induction.

Objectives: The objective of this study is to determine whether CYP mRNA level measurement is superior to the CYP enzyme activity measurement as a convenient high-throughput method for evaluating CYP induction potential using HepaRG cells.

Methods: QuantiGene Plex 2.0 Assay and LC/MS/MS. mRNA expression levels and enzyme activities of CYP1A2, CYP2B6, and CYP3A in HepaRG cells treated with prototypical inducers of each CYP isoform [omeprazole (OME) for CYP1A2, phenobarbital (PB) for CYP2B6, and rifampicin (RIF) for CYP3A] were evaluated.

Results: Although the activities of CYP2B6 and CYP3A were induced by treatment with PB and RIF, we found that the activity of phenacetin O-deethylase (PHOD), which is known as a marker of the activity of CYP1A2, was also enhanced by treatment with these non-CYP1A2 inducers in HepaRG cells. Based on previously published reports, we hypothesized that the expression ratio of CYP3A to CYP1A2 is much higher in HepaRG cells than in human hepatocytes; this may result in a nonnegligible contribution of CYP3A to the PHOD reaction in HepaRG cells. Studies using CYP3A inhibitor and pregnane X receptor-knockout HepaRG cells supported this hypothesis.

Conclusion: The measurement of mRNA serves as a higher reliable indicator for the evaluation of CYP induction potential when using HepaRG cells.

Keywords: CYP induction, HepaRG cells, QuantiGene Plex 2.0 assay, drug–drug interaction, PXR-knockout HepaRG cells, hepatocytes.

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Article Details

VOLUME: 12
ISSUE: 1
Year: 2018
Page: [14 - 23]
Pages: 10
DOI: 10.2174/1872312812666180119114013
Price: $58

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