title: Treatment of human immunodeficiency virus type 1 (HIV-1)-infected cells with combinations of HIV-1-specific inhibitors results in a different resistance pattern than does treatment with single-drug therapy.
abstract: Human immunodeficiency virus type 1 (HIV-1)-infected CEM cells were treated by the HIV-1-specific inhibitors bis-heteroarylpiperazine (BHAP), 4,5,6,7-tetrahydro-5-methylimidazo[4,5,1-jk][1,4]benzodiazepin-2(1 H)-on e (TIBO) R82913, nevirapine, and the N3-methylthymine derivative of [2',5'-bis-O-(tert-butyldimethylsilyl)-beta-D-ribofuranosyl]-3'-spiro- 5''-(4''-amino-1'',2''-oxathiole-2'',2''-dioxide) (TSAO-m3T), as single agents or in combination, at escalating concentrations. When used individually, the compounds led to the emergence of drug-resistant virus strains within two to five subcultivations. The resulting strains were designated HIV-1/BHAP, HIV-1/TIBO, HIV-1/Nev, and HIV-1/TSAO-m3T, respectively. The mutant viruses showed the following amino acid substitutions in their reverse transcriptase (RT): Leu-100-->Ile for HIV-1/BHAP; Lys-103-->Asn for HIV-1/TIBO; Val-106-->Ala for HIV-1/Nev; and Glu-138-->Lys for HIV-1/TSAO-m3T. Both the Tyr-181-->Cys and Val-106-->Ala mutations were found in another mutant emerging following treatment with nevirapine at escalating concentrations. The BHAP-resistant virus remained fully sensitive to the inhibitory effects of nevirapine and TSAO-m3T, whereas the TSAO-m3T-resistant virus remained fully sensitive to the inhibitory effects of nevirapine and BHAP. When different pairs of nonnucleoside RT inhibitors (i.e., BHAP plus TSAO-m3T, nevirapine plus TSAO-m3T, TIBO plus TSAO-m3T, nevirapine plus TIBO, and BHAP plus nevirapine) were used, resistant virus emerged as fast as with single-drug therapy. In all cases the Tyr-181-->Cys mutation appeared; the virus showed markedly reduced sensitivity to all HIV-1-specific inhibitors but retained sensitivity to 2',3'-dideoxynucleoside analogs such as zidovudine, ddC, and ddI. Our findings argue against simultaneous combination of two different nonnucleoside RT inhibitors that are unable to inhibit HIV-1 mutant strains containing the Tyr-181-->Cys mutation when administered as single drugs.
authors.affiliation: Rega Institute for Medical Research, Katholieke Universiteit Leuven, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Balzarini
authors.forename: A
authors.initials: A
authors.lastname: Karlsson
authors.forename: M J
authors.initials: MJ
authors.lastname: Pérez-Pérez
authors.forename: M J
authors.initials: MJ
authors.lastname: Camarasa
authors.forename: W G
authors.initials: WG
authors.lastname: Tarpley
authors.forename: E
authors.initials: E
authors.lastname: De Clercq
mesh_terms: D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000633:toxicity*; D001569:Benzodiazepines / Q000633:toxicity; D002460:Cell Line; D015224:Dideoxynucleosides / Q000633:toxicity; D004347:Drug Interactions; D004352:Drug Resistance, Microbial / Q000502:physiology*; D054303:HIV Reverse Transcriptase; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006801:Humans; D007093:Imidazoles / Q000633:toxicity; D016296:Mutagenesis; D019829:Nevirapine; D010879:Piperazines / Q000633:toxicity*; D011725:Pyridines / Q000633:toxicity; D011728:Pyridones / Q000633:toxicity; D012194:RNA-Directed DNA Polymerase / Q000235:genetics; D013141:Spiro Compounds; D013936:Thymidine / Q000031:analogs & derivatives / Q000633:toxicity; D014529:Uridine / Q000031:analogs & derivatives
chemical_list: D000998:Antiviral Agents; D015224:Dideoxynucleosides; D007093:Imidazoles; D010879:Piperazines; D011725:Pyridines; D011728:Pyridones; D013141:Spiro Compounds; D001569:Benzodiazepines; C067413:R-82913; D019829:Nevirapine; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase; D013936:Thymidine; C075132:TSAO-T; D014529:Uridine