title: Nevirapine modulation of paraoxonase-1 in the liver: An in vitro three-model approach.
abstract: BACKGROUND
  Nevirapine is associated with severe hepatotoxicity, through the formation of reactive metabolites. Paraoxonase-1 (PON-1) is a promiscuous enzyme involved in the metabolism of xeno- and endobiotics and proposed as a biomarker of hepatotoxicity. The aim of this work was to explore the effects of nevirapine and its phase I metabolites, 2-hydroxy-nevirapine and 12-hydroxy-nevirapine, on PON-1 activities.
  
  
  METHODS
  2D and 3D primary cultures of rat hepatocytes, and also HepG2 2D cell cultures, were exposed to nevirapine, 2-hydroxy-nevirapine, and 12-hydroxy-nevirapine. The paraoxonase (POase), arylesterase (AREase) and lactonase (LACase) activities of PON-1 were quantified.
  
  
  RESULTS
  Effects of nevirapine and its metabolites were only observed in the 3D cell model. Both nevirapine and 12-hydroxy-nevirapine increased POase (p<0.05, p<0.01) and LACase activities (p<0.05, p<0.001). The AREase activity was increased only upon 12-hydroxy-nevirapine exposure (p<0.01). These modulatory effects were observed at 300μM concentrations of nevirapine and 12-hydroxy-nevirapine.
  
  
  CONCLUSIONS
  The formation of 12-hydroxy-nevirapine seems to be the main factor responsible for the increase of PON-1 activities induced by nevirapine exposure. This effect was only observed in the 3D model, suggesting that an in vivo-like system is necessary for this modulation to occur. The present data suggest that the 3D model is a more suitable in vitro model than the conventional ones to explore drug effects on PON-1.
authors.affiliation: Centro de Estudos de Doenças Crónicas (CEDOC), NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal. Electronic address: aline.marinho@fcm.unl.pt.
authors.forename: Aline T
authors.initials: AT
authors.lastname: Marinho
authors.affiliation: Centro de Estudos de Doenças Crónicas (CEDOC), NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal. Electronic address: clara.dias@fcm.unl.pt.
authors.forename: Clara G
authors.initials: CG
authors.lastname: Dias
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; Centro de Química Estrutural (CQE), Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal. Electronic address: pfpinheiro@gmail.com.
authors.forename: Pedro F
authors.initials: PF
authors.lastname: Pinheiro
authors.affiliation: Centro de Estudos de Doenças Crónicas (CEDOC), NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal. Electronic address: ar.lemos@campus.fct.unl.pt.
authors.forename: Ana Rita
authors.initials: AR
authors.lastname: Lemos
authors.affiliation: Centro de Química Estrutural (CQE), Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal. Electronic address: alexandra.antunes@tecnico.ulisboa.pt.
authors.forename: Alexandra M M
authors.initials: AM
authors.lastname: Antunes
authors.affiliation: Centro de Química Estrutural (CQE), Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal. Electronic address: matilde.marques@tecnico.ulisboa.pt.
authors.forename: M Matilde
authors.initials: MM
authors.lastname: Marques
authors.affiliation: Centro de Estudos de Doenças Crónicas (CEDOC), NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal. Electronic address: emilia.monteiro@fcm.unl.pt.
authors.forename: Emília C
authors.initials: EC
authors.lastname: Monteiro
authors.affiliation: Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal. Electronic address: jmiranda@ff.ulisboa.pt.
authors.forename: Joana P
authors.initials: JP
authors.lastname: Miranda
authors.affiliation: Centro de Estudos de Doenças Crónicas (CEDOC), NOVA Medical School/Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo dos Mártires da Pátria, 130, 1169-056 Lisboa, Portugal. Electronic address: sofia.pereira@fcm.unl.pt.
authors.forename: Sofia A
authors.initials: SA
authors.lastname: Pereira
mesh_terms: D000818:Animals; D019380:Anti-HIV Agents / Q000494:pharmacology*; D043303:Aryldialkylphosphatase / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism*; D002478:Cells, Cultured; D005260:Female; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000378:metabolism; D019829:Nevirapine / Q000494:pharmacology*; D017208:Rats, Wistar
chemical_list: D019380:Anti-HIV Agents; D019829:Nevirapine; D002265:Carboxylic Ester Hydrolases; C019103:delta-lactonase; C019734:arylesterase; D043303:Aryldialkylphosphatase
keywords: 3D cultures; Arylesterase activity; HepG2 cell line; Lactonase activity; Nevirapine; Paraoxonase activity