Limited applicability of 7-methoxy-4-trifluoro-methylcoumarin as a CYP2C9-selective substrate

Pálma Porrogi, L. Kóbori, Krisztina Kölahmy, Judit Gulyás, L. Vereczkey, K. Monostory

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Fluorometric substrates selective for various cytochrome P450 isoforms (P450s) have great advantages in in vitro enzyme inhibition and induction studies because they are highly sensitive and suitable for rapid screening. 7-Methoxy-4-trifluoromethylcoumarin (MFC) has been reported as a CYP2C9-selective substrate. The present study investigated the relative catalytic selectivity of several human P450s in the O-demethylation of MFC and the applicability of MFC as a probe substrate for CYP2C9. The CYP2C9-selectivity in liver microsomes was not supported by the correlation analysis within a series of microsomes from individual donors or by studies using chemical inhibitors. MFC O-demethylation of microsomes did not correlate with tolbutamide 4-hydroxylation, the classical CYP2C9-marker activity, suggesting the possible participation of some of the other P450s. Results of inhibition studies using model P450 inhibitors also brought the CYP2C9-selectivity of MFC O-demethylation into question. In microsomes containing cDNA-expressed individual P450s, CYP2B6 and CYP2E1 seemed to be the most active in the O-demethylation of MFC. Our results support the participation of several P450 enzymes (CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2E1 and CYP3A4) in MFC O-dealkylation. Therefore, MFC cannot be considered a suitable probe substrate in models that express several P450s, such as liver microsomes or primary hepatocytes. Moreover, MFC is a more potent fluorogenic substrate for CYP2B6 and CYP2E1 than for CYP2C9 in microsomes containing cDNA-expressed P450s.

Original languageEnglish
Pages (from-to)972-979
Number of pages8
JournalPharmacological Reports
Volume60
Issue number6
Publication statusPublished - 2008

Fingerprint

Protein Isoforms
Microsomes
Cytochrome P-450 CYP2E1
Liver Microsomes
Cytochrome P-450 Enzyme System
Complementary DNA
Dealkylation
Cytochrome P-450 CYP3A
Tolbutamide
Enzyme Induction
Hydroxylation
Cytochrome P-450 CYP2C9
Fluorescent Dyes
Hepatocytes
Cytochrome P-450 CYP2B6

Keywords

  • 7-methoxy-4-trifluoromethylcoumarin O-demethylation
  • CYP2C9-selectivity
  • Drug-drug interaction
  • Fluorogenic substrate
  • High-throughput screening

ASJC Scopus subject areas

  • Pharmacology

Cite this

Limited applicability of 7-methoxy-4-trifluoro-methylcoumarin as a CYP2C9-selective substrate. / Porrogi, Pálma; Kóbori, L.; Kölahmy, Krisztina; Gulyás, Judit; Vereczkey, L.; Monostory, K.

In: Pharmacological Reports, Vol. 60, No. 6, 2008, p. 972-979.

Research output: Contribution to journalArticle

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AU - Porrogi, Pálma

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AU - Monostory, K.

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