Human serum alpha 1 acid glycoprotein reduces uptake, intracellular concentration, and antiviral activity of A-80987, an inhibitor of the human immunodeficiency virus type 1 protease.
The therapeutic utility of a human immunodeficiency virus type 1 (HIV-1) protease inhibitor may depend on its intracellular concentration, which is a property of its uptake, metabolism, and/or efflux. Previous studies in our laboratory indicated that the addition of alpha 1 acid glycoprotein (alpha 1 AGP) to the medium markedly increased the amount of the drug required to limit infection in vitro. In this study, physiologically relevant concentrations of alpha 1 AGP and a radiolabeled inhibitor, A-80987, were used to determine both the uptake and activity of the agent in HIV-1-infected human peripheral blood mononuclear cells and cell lines. Both the uptake and efflux of 14C-labeled A-80987 were rapid (t1/2, < 5 min). Uptake of the drug was linearly dependent on the concentration but insensitive to the metabolic inhibitors KF, sodium cyanide, or CCCP (carbonyl cyanide m-chlorophenyl hydrazone). The amount of A-80987 which entered the cells was inversely proportional to the concentration of alpha 1 AGP (r2, 0.99) and directly proportional to the amount of extracellular non-protein-bound drug (r2, 0.99). Most importantly, the antiviral activity of the drug in HIV-1-infected peripheral blood mononuclear cells and MT-2 cells was directly related to the amount of intracellular A-80987. This study demonstrates that A-80987 binds to alpha 1 AGP, resulting in a free fraction below 10%. Cellular uptake of A-80987 is proportionally decreased in the presence of alpha 1 AGP, which results in less-than-expected antiviral activity. Importantly, we demonstrate for the first time that the inhibition of HIV protease is highly correlated with the amount of intracellular inhibitor.
Bilello
J A
JA
Department of Medicine, Albany Medical College, New York 12208, USA.
Bilello
P A
PA
Stellrecht
K
K
Leonard
J
J
Norbeck
D W
DW
Kempf
D J
DJ
Robins
T
T
Drusano
G L
GL
D002460:Cell Line; D017320:HIV Protease Inhibitors / Q000378:metabolism / Q000493:pharmacokinetics*; D015497:HIV-1 / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D009961:Orosomucoid / Q000378:metabolism / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D011725:Pyridines / Q000378:metabolism / Q000493:pharmacokinetics*; D012367:RNA, Viral / Q000187:drug effects
D017320:HIV Protease Inhibitors; D009961:Orosomucoid; D011725:Pyridines; D012367:RNA, Viral; C092970:A 80987