title: Clonal selection of HIV type 1 variants associated with resistance to foscarnet in vitro: confirmation by molecular evolutionary analysis.
abstract: Foscarnet (trisodium phosphonoformate, PFA) is an effective inhibitor of retroviral reverse transcriptase (RT) and is known to block the replication of human immunodeficiency virus type 1 (HIV-1). In this article we analyzed the evolutionary process in generating HIV-1 strains related to drug resistance, using PFA as a selective pressure. PFA inhibited virus replication and protected the virus-induced cell killing, but it did not completely eliminate HIV-1 during the course of 7 weeks of treatment. The nucleotide sequence of the 859-bp DNA fragment spanning the core region of the HIV-1 pol gene was determined for 51 clones obtained from genomic DNA of the HIV-1-infected cells at different time points during PFA treatment. The nucleotide sequence analysis documented the presence of a minor HIV-1 variant prior to the PFA treatment. Molecular evolutionary techniques were utilized to analyze how the minor HIV-1 clones became predominant during this evolutionary process under the selective pressure of PFA. A phylogenetic tree analysis divided these 51 HIV-1 clones into 3 groups. One of the groups consisted of the clones associated with the resistance to PFA. The clones belonging to this group became predominant over time during the course of PFA treatment. Thus, the acquisition of PFA resistance by HIV-1 was considered to be due to clonal selection. Furthermore, among the various amino acid substitutions observed, the substitution of arginine at position 172 by lysine (Arg172Lys) clearly distinguished this group from the others. Since the consistent amino acid substitution observed here has not been identified in the HIV-1 strains resistant to other RT inhibitors, PFA in combination with other RT inhibitors is considered to be a feasible candidate for a convergent combined chemotherapy against HIV-1 in the treatment of patients with AIDS and related conditions.
authors.affiliation: Department of Molecular Genetics, Nagoya City University Medical School, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nakano
authors.forename: H
authors.initials: H
authors.lastname: Morozumi
authors.forename: S
authors.initials: S
authors.lastname: Inuzuka
authors.forename: M
authors.initials: M
authors.lastname: Nagata
authors.forename: Y
authors.initials: Y
authors.lastname: Taguchi
authors.forename: M
authors.initials: M
authors.lastname: Mizokami
authors.forename: T
authors.initials: T
authors.lastname: Okamoto
mesh_terms: D000595:Amino Acid Sequence; D019380:Anti-HIV Agents / Q000494:pharmacology*; D001120:Arginine / Q000235:genetics; D005075:Biological Evolution; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004279:DNA, Viral / Q000032:analysis; D004352:Drug Resistance, Microbial / Q000235:genetics; D017245:Foscarnet / Q000494:pharmacology*; D015967:Gene Expression Regulation, Viral; D015751:Genes, pol; D014644:Genetic Variation; D015658:HIV Infections / Q000188:drug therapy* / Q000235:genetics*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics* / Q000502:physiology; D006801:Humans; D008239:Lysine / Q000235:genetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013601:T-Lymphocytes; D014779:Virus Replication / Q000187:drug effects
chemical_list: D019380:Anti-HIV Agents; D004279:DNA, Viral; D017245:Foscarnet; D001120:Arginine; D008239:Lysine