title: 3'-Azido-3'-deoxythymidine (AZT) mediates cross-resistance to nucleoside analogs in the case of AZT-resistant human immunodeficiency virus type 1 variants.
abstract: Difficulties in deciphering the mechanisms of 3'-azido-3'-deoxythymidine (AZT)-resistance by human immunodeficiency virus type 1 (HIV-1) variants are due in part to an inability to reconstitute resistance in vitro using AZT-resistant reverse transcriptases. We decided to characterize mechanisms of AZT resistance in tissue culture infections by studying the ability of drug-resistant viruses to synthesize viral DNA in the presence or absence of drug. Through use of PCR amplifications, we discovered an AZT-mediated stimulation of reverse transcription by AZT-resistant viruses carrying the M41L and T215Y mutations that can apparently override the inhibitory effects of AZT-5'-triphosphate. In addition, the presence of AZT also causes viruses containing the M41L and T215Y substitutions to have diminished sensitivity to other nucleoside analogs (i.e., ddC, ddI, and d4T). This AZT-mediated cross-resistance may help to explain the virological failure of treatment regimens that included ddI plus AZT or ddC plus AZT in situations in which the T215Y and/or M41L mutations were present (F. Brun-Vézinet, C. Boucher, C. Loveday, D. Descamps, V. Fauveau, J. Izopet, D. Jeffries, S. Kaye, C. Krzyanowski, A. Nunn, R. Schuurman, J. M. Seigneurin, C. Tamalet, R. Tedder, J. Weber, and G. J. Weverling, Lancet 350:983-990, 1997). Our results suggest that the use of AZT may be contraindicated in those patients for whom resistance to this compound (M41L and/or T215Y) has been demonstrated.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA. eja3@po.cwru.edu
authors.forename: E J
authors.initials: EJ
authors.lastname: Arts
authors.forename: M E
authors.initials: ME
authors.lastname: Quiñones-Mateu
authors.forename: J L
authors.initials: JL
authors.lastname: Albright
authors.forename: J P
authors.initials: JP
authors.lastname: Marois
authors.forename: C
authors.initials: C
authors.lastname: Hough
authors.forename: Z
authors.initials: Z
authors.lastname: Gu
authors.forename: M A
authors.initials: MA
authors.lastname: Wainberg
mesh_terms: D019380:Anti-HIV Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial / Q000235:genetics; D016679:Genome, Viral; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics*; D006801:Humans; D019169:Jurkat Cells; D009154:Mutation; D015215:Zidovudine / Q000031:analogs & derivatives / Q000494:pharmacology*
chemical_list: D019380:Anti-HIV Agents; D015215:Zidovudine