title: Different selection patterns of resistance and cross-resistance to HIV-1 agents targeting CCR5.
abstract: OBJECTIVE
  Identification of CCR5 as an antiretroviral target led to the development of several CCR5 antagonists in clinical trials and the approval of maraviroc. Evaluating the mechanism of drug resistance to CCR5 agents may have implications in the clinical development of this class of agents. We have analysed the resistance profile of two R5 HIV-1 strains [BaL and a clinical isolate (CI)] after long-term passage in cell culture in the presence of TAK-779, the first developed non-peptidic small molecule targeting CCR5.
  
  
  METHODS
  Genotypic and phenotypic tests were used to evaluate the resistance of virus isolated from cell culture in the presence of the CCR5 inhibitor TAK-779.
  
  
  RESULTS
  Mutations conferring resistance appeared in the gp120 sequence but were not confined to the V3 loop region, and both strains had a different mutation pattern. Recombination of the env gene of the BaL-derived resistant virus into the HIV-1 HXB2 wild-type backbone conferred resistance to TAK-779 and cross-resistance to maraviroc, with 63- and 11-fold changes in their EC(50) (50% effective concentration), respectively, together with an apparent reduction of the maximal plateau inhibition (MPI) of TAK-779 but not of maraviroc. Conversely, the resistant CI viruses showed an approximately 50% reduction in MPI for both TAK-779 and maraviroc.
  
  
  CONCLUSIONS
  We confirm that different pathways to the generation of CCR5 drug resistance/cross-resistance may occur that strongly depend on cell culture conditions, CCR5 availability and the genetic background of the HIV strain. Our study provides complementary information to understand the complexity of resistance to CCR5 antagonists.
authors.affiliation: Retrovirology Laboratory IrsiCaixa, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, 08916 Badalona, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Armand-Ugón
authors.forename: Gemma
authors.initials: G
authors.lastname: Moncunill
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Gonzalez
authors.forename: MariaPau
authors.initials: M
authors.lastname: Mena
authors.forename: Ester
authors.initials: E
authors.lastname: Ballana
authors.forename: Bonaventura
authors.initials: B
authors.lastname: Clotet
authors.forename: José A
authors.initials: JA
authors.lastname: Esté
mesh_terms: D000577:Amides / Q000494:pharmacology*; D019380:Anti-HIV Agents / Q000494:pharmacology*; D065100:CCR5 Receptor Antagonists; D002460:Cell Line; D002478:Cells, Cultured; D003510:Cyclohexanes / Q000494:pharmacology; D024882:Drug Resistance, Viral; D015699:HIV Envelope Protein gp120 / Q000235:genetics; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D020128:Inhibitory Concentration 50; D007963:Leukocytes, Mononuclear / Q000821:virology; D000077592:Maraviroc; D008826:Microbial Sensitivity Tests; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D014230:Triazoles / Q000494:pharmacology
chemical_list: D000577:Amides; D019380:Anti-HIV Agents; D065100:CCR5 Receptor Antagonists; D003510:Cyclohexanes; D015699:HIV Envelope Protein gp120; D000644:Quaternary Ammonium Compounds; D014230:Triazoles; C514793:gp120 protein, Human immunodeficiency virus 1; C119369:TAK 779; D000077592:Maraviroc