title: Addition of E138K to R263K in HIV integrase increases resistance to dolutegravir, but fails to restore activity of the HIV integrase enzyme and viral replication capacity.
abstract: BACKGROUND
  The results of several clinical trials suggest that the integrase inhibitor dolutegravir may be less prone than other drugs to the emergence of HIV drug resistance mutations in treatment-naive patients. We have shown that the R263K mutation commonly emerged during tissue culture selection studies with dolutegravir and conferred low levels of resistance to this drug while simultaneously diminishing both HIV replication capacity and integrase enzymatic activity. E138K has been identified as a secondary mutation for dolutegravir in selection studies and has also been observed as a secondary mutation in the clinic for the integrase inhibitors raltegravir and elvitegravir.
  
  
  METHODS
  We used biochemical cell-free strand-transfer assays and tissue culture assays to characterize the effects of the E138K/R263K combination of mutations on resistance to dolutegravir, integrase enzyme activity and HIV-1 replication capacity.
  
  
  RESULTS
  We show here that the addition of the E138K substitution to R263K increased the resistance of HIV-1 to dolutegravir but failed to restore viral replication capacity, integrase strand-transfer activity and integration within cellular DNA. We also show that the addition of E138K to R263K did not increase the resistance to raltegravir or elvitegravir. The addition of the E138K substitution to R263K was also less detrimental to integrase strand-transfer activity and integration than a different secondary mutation at position H51Y that had also been selected in culture.
  
  
  CONCLUSIONS
  The E138K substitution failed to restore the defect in viral replication capacity that is associated with R263K, confirming previous selection studies that failed to identify compensatory mutation(s) for the latter primary mutation. This study suggests that the R263K resistance pathway may represent an evolutionary dead end for HIV in treatment-naive individuals who are treated with dolutegravir and will need to be confirmed by the long-term use of dolutegravir in the clinic.
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Québec, Canada.
authors.forename: Thibault
authors.initials: T
authors.lastname: Mesplède
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Québec, Canada Department of Microbiology and Immunology, Faculty of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Nathan
authors.initials: N
authors.lastname: Osman
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Québec, Canada Department of Microbiology and Immunology, Faculty of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Melissa
authors.initials: M
authors.lastname: Wares
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Québec, Canada Division of Experimental Medicine, Faculty of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Quashie
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Québec, Canada Division of Experimental Medicine, Faculty of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Said
authors.initials: S
authors.lastname: Hassounah
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Québec, Canada Department of Microbiology and Immunology, Faculty of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Kaitlin
authors.initials: K
authors.lastname: Anstett
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Québec, Canada.
authors.forename: Yingshan
authors.initials: Y
authors.lastname: Han
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Québec, Canada Department of Microbiology and Immunology, Faculty of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Diane N
authors.initials: DN
authors.lastname: Singhroy
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Québec, Canada Department of Microbiology and Immunology, Faculty of Medicine, McGill University, Montréal, Québec, Canada Division of Experimental Medicine, Faculty of Medicine, McGill University, Montréal, Québec, Canada mark.wainberg@mcgill.ca.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wainberg
mesh_terms: D019943:Amino Acid Substitution; D002460:Cell Line; D024882:Drug Resistance, Viral / Q000235:genetics*; D004789:Enzyme Activation / Q000187:drug effects; D019427:HIV Integrase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D019428:HIV Integrase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics*; D006575:Heterocyclic Compounds, 3-Ring / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008968:Molecular Conformation; D009154:Mutation; D010078:Oxazines; D010879:Piperazines; D011485:Protein Binding; D011728:Pyridones; D016662:Virus Integration / Q000235:genetics; D014779:Virus Replication / Q000187:drug effects*; D000099226:Dolutegravir
chemical_list: D019427:HIV Integrase; D019428:HIV Integrase Inhibitors; D006575:Heterocyclic Compounds, 3-Ring; D010078:Oxazines; D010879:Piperazines; D011728:Pyridones; D000099226:Dolutegravir
keywords: HIV-1; antiviral; integrase inhibitors