title: Human fetal ventricular cardiomyocyte, RL-14 cell line, is a promising model to study drug metabolizing enzymes and their associated arachidonic acid metabolites.
abstract: BACKGROUND
  RL-14 cells, human fetal ventricular cardiomyocytes, are a commercially available cell line that has been established from non-proliferating primary cultures derived from human fetal heart tissue. However, the expression of different drug metabolizing enzymes (DMEs) in RL-14 cells has not been elucidated yet. Therefore, the main objectives of the current work were to investigate the capacity of RL-14 cells to express different cytochrome P450 (CYP) isoenzymes and correlate this expression to primary cardiomyocytes.
  
  
  METHODS
  The expression of CYP isoenzymes was determined at mRNA, protein and catalytic activity levels using real time-PCR, Western blot analysis and liquid chromatography-electron spray ionization-mass spectrometry (LC-ESI-MS), respectively.
  
  
  RESULTS
  Our results showed that RL-14 cells constitutively express CYP ω-hydroxylases, CYP1A, 1B, 4A and 4F; CYP epoxygenases, CYP2B, 2C and 2J; in addition to soluble epoxide hydrolayse (EPHX2) at mRNA and protein levels. The basal expression of CYP ω-hydroxylases, epoxygenases and EPHX2 was supported by the ability of RL-14 cells to convert arachidonic acid to its biologically active metabolites, 20-hydroxyeicosatetraenoic acids (20-HETEs), 14,15-epoxyeicosatrienoic acids (14,15-EET), 11,12-EET, 8,9-EET, 5,6-EET, 14,15-dihydroxyeicosatrienoic acid (14,15-DHET), 11,12-DHET, 8,9-DHET and 5,6-DHET. Furthermore, RL-14 cells express CYP epoxygenases and ω-hydroxylase at comparable levels to those expressed in adult and fetal human primary cardiomyocytes cells implying the importance of RL-14 cells as a model for studying DMEs in vitro. Lastly, different CYP families were induced in RL-14 cells using 2,3,7,8-tetrachlorodibenzo-p-dioxin and fenofibrate at mRNA and protein levels.
  
  
  CONCLUSIONS
  The current study provides the first evidence that RL-14 cells express CYP isoenzymes at comparable levels to those expressed in the primary cells and thus offers a unique in vitro model to study DMEs in the heart.
authors.affiliation: Faculty of Pharmacy & Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.
authors.forename: Zaid H
authors.initials: ZH
authors.lastname: Maayah
authors.affiliation: Faculty of Pharmacy & Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.
authors.forename: Osama H
authors.initials: OH
authors.lastname: Elshenawy
authors.affiliation: Faculty of Pharmacy & Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.
authors.forename: Hassan N
authors.initials: HN
authors.lastname: Althurwi
authors.affiliation: Faculty of Pharmacy & Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.
authors.forename: Ghada
authors.initials: G
authors.lastname: Abdelhamid
authors.affiliation: Faculty of Pharmacy & Pharmaceutical Sciences, University of Alberta, Edmonton, Canada. Electronic address: aelkadi@ualberta.ca.
authors.forename: Ayman O S
authors.initials: AO
authors.lastname: El-Kadi
mesh_terms: D016718:Arachidonic Acid / Q000378:metabolism*; D002478:Cells, Cultured; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D011345:Fenofibrate / Q000494:pharmacology*; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D016718:Arachidonic Acid; D003577:Cytochrome P-450 Enzyme System; D011345:Fenofibrate
keywords: 20-HETE; Cytochrome P450; EETs; Epoxyeicosatrienoic acids; Hydroxyeicosatetraenoic acid; RL-14 cells