title: Synergistic drug interactions of an HIV-1 protease inhibitor with AZT in different in vitro models of HIV-1 infection.
abstract: Synthetic peptide mimetic inhibitors of HIV-1 protease effectively block spread of infectious virus in acutely infected T-cells. These compounds also inhibit production of infectious virions from chronically infected T-cell lines. In order to determine the potential for drug interaction effects on antiviral activity, an HIV-1 protease inhibitor (SK&F 108922) and AZT were studied in three different in vitro models of HIV-1 infection of T-cell lines, specifically, (1) acutely infected cells infected at low multiplicity, (2) HIV-1 chronically-infected cells and (3) co-cultivations of chronically infected with non-infected cells. Upon co-treatment, these compounds demonstrated synergy in Molt4 or H9 cells acutely infected with HIV-1 strain IIIB. Either compound alone was a potent inhibitor of HIV-1 in co-cultivations of uninfected and chronically infected cells. In combination treatments of co-cultures, SK&F 108922 demonstrated strong synergy with AZT. Treatment of H9/IIIB chronically infected cells demonstrated no inhibitory effect by AZT treatment (EC50 = > 100 microM) whereas SK&F 108922 was inhibitory (EC50 = 3 microM). Upon co-treatment of H9/IIIB chronically infected cultures with both compounds, the antiviral activity was similar to that of the protease inhibitor alone suggesting no drug interaction. In the co-cultivation experiments, AZT's antiviral effect was most likely due to blocking spread of acute infection to uninfected cells in the culture. No antagonistic effects were observed with AZT and SK&F 108922 co-treatments. These results clearly demonstrate that an HIV-1 protease inhibitor can exert a potent antiviral effect on chronically infected T-cells in contrast to AZT and is capable of potent synergy with AZT in acute and co-culture in vitro infection models.
authors.affiliation: Department of Molecular Virology and Host Defense, SmithKline Beecham Research Laboratories, King of Prussia, PA 19406.
authors.forename: D M
authors.initials: DM
authors.lastname: Lambert
authors.forename: H
authors.initials: H
authors.lastname: Bartus
authors.forename: A V
authors.initials: AV
authors.lastname: Fernandez
authors.forename: C
authors.initials: C
authors.lastname: Bratby-Anders
authors.forename: J J
authors.initials: JJ
authors.lastname: Leary
authors.forename: G B
authors.initials: GB
authors.lastname: Dreyer
authors.forename: B W
authors.initials: BW
authors.lastname: Metcalf
authors.forename: S R
authors.initials: SR
authors.lastname: Petteway
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy*; D000595:Amino Acid Sequence; D002460:Cell Line; D002908:Chronic Disease; D004357:Drug Synergism; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D054303:HIV Reverse Transcriptase; D015497:HIV-1 / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D008954:Models, Biological; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology*; D012194:RNA-Directed DNA Polymerase / Q000096:biosynthesis / Q000378:metabolism; D014779:Virus Replication / Q000187:drug effects; D015215:Zidovudine / Q000494:pharmacology*
chemical_list: D017320:HIV Protease Inhibitors; D009842:Oligopeptides; C083669:SK&F 108922; D015215:Zidovudine; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase