title: Anti-human immunodeficiency virus type 1 activity of novel 6-substituted 1-benzyl-3-(3,5-dimethylbenzyl)uracil derivatives.
abstract: Nonnucleoside reverse transcriptase (RT) inhibitors (NNRTIs) are important components of current combination therapies for human immunodeficiency virus type 1 (HIV-1) infection. In screening of chemical libraries, we found 6-azido-1-benzyl-3-(3,5-dimethylbenzyl)uracil (AzBBU) and 6-amino-1-benzyl-3-(3,5-dimethylbenzyl)uracil (AmBBU) to be highly active and selective inhibitors of HIV-1 replication in vitro. To determine the resistance profiles of these compounds, we conducted a long-term culture of HIV-1-infected MT-4 cells with escalating concentrations of each compound. After serial passages of the infected cells, escape viruses were obtained, and they were more than 500-fold resistant to the uracil derivatives compared to the wild type. Sequence analysis was conducted for RT of the escape viruses at passages 12 and 24. The amino acid mutation Y181C in the polymerase domain of RT was detected for all escape viruses. Docking studies using the crystal structure of RT showed that AmBBU requires the amino acid residues Leu100, Val106, Tyr181, and Trp229 for exerting its inhibitory effect on HIV-1. Four additional amino acid changes (K451R, R461K, T468P, and D471N) were identified in the RNase H domain of RT; however, their precise role in the acquisition of resistance is still unclear. In conclusion, the initial mutation Y181C seems sufficient for the acquisition of resistance to the uracil derivatives AzBBU and AmBBU. Further studies are required to determine the precise role of each mutation in the acquisition of HIV-1 resistance.
authors.affiliation: Division of Antiviral Chemotherapy, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Paula
authors.initials: P
authors.lastname: Ordonez
authors.forename: Takayuki
authors.initials: T
authors.lastname: Hamasaki
authors.forename: Yohei
authors.initials: Y
authors.lastname: Isono
authors.forename: Norikazu
authors.initials: N
authors.lastname: Sakakibara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ikejiri
authors.forename: Tokumi
authors.initials: T
authors.lastname: Maruyama
authors.forename: Masanori
authors.initials: M
authors.lastname: Baba
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D019380:Anti-HIV Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001665:Binding Sites; D002460:Cell Line; D003198:Computer Simulation; D024882:Drug Resistance, Viral / Q000187:drug effects / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D017434:Protein Structure, Tertiary; D018894:Reverse Transcriptase Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D017421:Sequence Analysis; D054852:Small Molecule Libraries; D013601:T-Lymphocytes / Q000187:drug effects / Q000821:virology; D014498:Uracil / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology
chemical_list: C574279:6-amino-1-benzyl-3-(3,5-dimethylbenzyl)uracil; C574278:6-azido-1-benzyl-3-(3,5-dimethylbenzyl)uracil; D019380:Anti-HIV Agents; D018894:Reverse Transcriptase Inhibitors; D054852:Small Molecule Libraries; D014498:Uracil; D054303:HIV Reverse Transcriptase