title: Atorvastatin as a potential anti-malarial drug: in vitro synergy in combinational therapy with quinine against Plasmodium falciparum.
abstract: BACKGROUND
  Quinine (QN) remains the first line anti-malarial drug for the treatment of complicated malaria in Europe and Africa. The emergence of QN resistance has been documented. QN resistance is not yet a significant problem, but there is an urgent need to discover partners for use in combination with QN. The aim of the study was to assess the in vitro potentiating effects of atorvastatin (AVA), a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, in combination with QN against Plasmodium falciparum and to evaluate whether the effects of AVA could be associated with gene copy number or mutations in genes involved in QN resistance, such as pfcrt, pfmdr1, pfmrp and pfnhe.
  
  
  METHODS
  The susceptibilities to combination of AVA with QN were assessed against 21 parasite strains using the in vitro isotopic microtest. Genotypes and gene copy number were assessed for pfcrt, pfmdr1, pfmdr2, pfmrp genes. In addition, the number of DNNND, DDNHNDNHNN repeats in pfnhe-1 ms4760 and the ms4760 profile were determined for each strains of P. falciparum.
  
  
  RESULTS
  AVA demonstrated synergistic effects in combination with QN against 21 P. falciparum strains. The QN IC50 was reduced by 5% (0% to 15%; 95%CI: 1%-8%), 10% (3% to 23%; 95%CI: 7%-14%) and 22% (14% to 40%; 95%CI: 19%-25%) in presence of AVA at concentrations of 0.1, 0.5 and 1.0 microM, respectively. These reductions were all significant (p < 0.009). The reduction in the QN IC50 in presence of AVA was not significantly correlated with the QN IC50 (r = 0.22, P = 0.3288) or the AVA IC50 (r = 0.03, P = 0.8946). The synergistic effect of AVA in combination with QN was not significantly associated with polymorphisms in the pfcrt, pfmdr1, pfmrp, and pfnhe-1 genes that could be involved in QN resistance. The synergistic effect of AVA on QN responses was not significantly associated with pfmdr1 copy number (P = 0.0428).
  
  
  CONCLUSIONS
  The synergistic effect of AVA in combination with QN was found to be unrelated to mutations occurring in transport protein genes involved in QN drug resistance. The different mechanisms of drug uptake and/or mode of action for AVA compared to the other anti-malarial drugs, as well as the AVA-mediated synergy of the anti-malarial effect of QN, suggests that AVA will be a good candidate for combinatorial malaria treatment. All of these observations support calls for both an in vivo evaluation with pharmacokinetic component and clinical trials of AVA as an anti-malarial therapy.
authors.affiliation: Unité de Recherche en Biologie et Epidémiologie Parasitaires - Unité de Recherche pour les Maladies Infectieuses et Tropicales Emergentes - UMR 6236, Institut de Médecine Tropicale du Service de Santé des Armées, Marseille, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Parquet
authors.forename: Maud
authors.initials: M
authors.lastname: Henry
authors.forename: Nathalie
authors.initials: N
authors.lastname: Wurtz
authors.forename: Jerome
authors.initials: J
authors.lastname: Dormoi
authors.forename: Sébastien
authors.initials: S
authors.lastname: Briolant
authors.forename: Marine
authors.initials: M
authors.lastname: Gil
authors.forename: Eric
authors.initials: E
authors.lastname: Baret
authors.forename: Rémy
authors.initials: R
authors.lastname: Amalvict
authors.forename: Christophe
authors.initials: C
authors.lastname: Rogier
authors.forename: Bruno
authors.initials: B
authors.lastname: Pradines
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000962:Antimalarials / Q000494:pharmacology* / Q000627:therapeutic use; D000069059:Atorvastatin; D004351:Drug Resistance; D004357:Drug Synergism; D018628:Gene Dosage / Q000187:drug effects; D014644:Genetic Variation; D005838:Genotype; D006538:Heptanoic Acids / Q000494:pharmacology*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D016778:Malaria, Falciparum / Q000188:drug therapy / Q000235:genetics; D026901:Membrane Transport Proteins / Q000235:genetics; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics; D009154:Mutation; D021261:Parasitic Sensitivity Tests; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D015800:Protozoan Proteins / Q000235:genetics; D011758:Pyrroles / Q000494:pharmacology*; D011803:Quinine / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D018528:ATP-Binding Cassette Transporters; D000962:Antimalarials; D000069059:Atorvastatin; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D015800:Protozoan Proteins; D011758:Pyrroles; D011803:Quinine; C513498:Mdr1 protein, Plasmodium falciparum; C513499:Mdr2 protein, Plasmodium falciparum; C416369:PfCRT protein, Plasmodium falciparum; C059987:mdr gene protein, Plasmodium