title: Multiple mutations in human immunodeficiency virus-1 integrase confer resistance to the clinical trial drug S-1360.
abstract: OBJECTIVE
  Study of HIV-1 resistance development to the diketo analogue S-1360, the first HIV-1 integrase strand transfer inhibitor that has entered clinical development.
  
  
  METHODS
  HIV-1(IIIB) was passaged in cell culture in the presence of increasing concentrations of S-1360 (IIIB/S-1360(res)).
  
  
  METHODS
  The IIIB/S-1360(res) strains selected for 30, 50 and 70 passages in the presence of S-1360 were evaluated genotypically by sequencing analysis and phenotypically using the MT-4/MTT assay.
  
  
  RESULTS
  Multiple mutations, nine in total, emerged progressively in the catalytic domain of integrase as a result of the selection process. They included T66I and L74M that have both been associated with resistance against the diketo acid L-708,906. After 30, 50 and 70 passages in the presence of S-1360, IIIB/S-1360(res) displayed a four-, eight- and more than 62-fold reduced susceptibility for S-1360, respectively. Phenotypic cross-resistance to L-708,906 was modest for the IIIB/S-1360(res) strain selected during 50 passages, but pronounced for the strain selected during 70 passages. Interesting, all IIIB/S-1360(res) strains remained fully susceptible to the pyranodipyrimidine V-165, an integrase DNA binding inhibitor. Recombination of the mutant integrase genes into wild-type background by integrase-chimeric virus technology entirely reproduced the resistance profile of the IIIB/S-1360(res) strains. As for the replication kinetics of the selected and recombined strains, reduced replication fitness was measured for all strains when compared with their respective wild-type strains.
  
  
  CONCLUSIONS
  The accumulation of integrase mutations coincided with an increasing level of (cross-)resistance of IIIB/S-1360(res). Integrase-chimeric virus technology confirmed that the integrase mutations are indeed fully responsible for the resistance phenotype of IIIB/S-1360.
authors.affiliation: Rega Institute for Medical Research, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: Valery
authors.initials: V
authors.lastname: Fikkert
authors.forename: Anneleen
authors.initials: A
authors.lastname: Hombrouck
authors.forename: Barbara
authors.initials: B
authors.lastname: Van Remoortel
authors.forename: Marc
authors.initials: M
authors.lastname: De Maeyer
authors.forename: Christophe
authors.initials: C
authors.lastname: Pannecouque
authors.forename: Erik
authors.initials: E
authors.lastname: De Clercq
authors.forename: Zeger
authors.initials: Z
authors.lastname: Debyser
authors.forename: Myriam
authors.initials: M
authors.lastname: Witvrouw
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use*; D002478:Cells, Cultured; D002999:Clone Cells; D024882:Drug Resistance, Viral / Q000235:genetics*; D005663:Furans; D015658:HIV Infections / Q000188:drug therapy* / Q000235:genetics; D019427:HIV Integrase / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000379:methods; D014230:Triazoles; D014779:Virus Replication / Q000235:genetics
chemical_list: D019380:Anti-HIV Agents; D005663:Furans; C451733:S 1360; D014230:Triazoles; D019427:HIV Integrase