Metabolism and mode of selective inhibition of human immunodeficiency virus replication by 3'-azido-2',3'-dideoxy-5-iodouridine and 3'-azido-2',3'-dideoxy-5-bromouridine
| Autor: | E. Michael August, William H. Prusoff, Lin Tai-Shun, Evelyn M. Birks, Qian He-Ying, Usha A. Thombre |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
DNA polymerase
Virus Replication Antiviral Agents Thymidine Kinase Biochemistry Thymidylate kinase Cell Line chemistry.chemical_compound Deoxyadenosine Idoxuridine Humans Phosphorylation Pharmacology biology Uracil DNA DNA Polymerase II Deoxyuridine HIV Reverse Transcriptase Reverse transcriptase Uridine Kinetics chemistry Thymidine kinase Protein Biosynthesis HIV-1 biology.protein RNA Reverse Transcriptase Inhibitors Nucleoside-Phosphate Kinase Thymidine Cell Division |
| Zdroj: | Biochemical Pharmacology. 45:223-230 |
| ISSN: | 0006-2952 |
| Popis: | 3'-Azido-2',3'-dideoxy-5-iodouridine (AzIdUrd) and 3'-azido-2',3'-dideoxy-5-bromouridine (AzBdUrd), previously shown to be potent and selective inhibitors of human immunodeficiency virus replication in vitro were minimally toxic to the uninfected human lymphoid cell line H9 ( ic 50 = 197 and 590 μM, respectively). Both compounds strongly inhibited the incorporation of [ 3 H]thymidine but not [ 3 H]deoxyadenosine into DNA, and we observed no significant inhibition of [ 3 H]uridine incorporation into RNA or [ 3 H]amino acid incorporation into protein. Exposure of H9 cells to AzIdUrd or AzBdUrd (100 μM, 24 hr) and pulse-labeling with [ 3 H]thymidine resulted in approximately 80% reduction in levels of tritiated dTMP, dTDP, and dTTP relative to control. [[su125]I]AzIdUrd was phosphorylated rapidly in H9 cells with the monophosphate accounting for over 90% of total soluble radioactivity. A relatively low but stable level of AzIdUTP was maintained over a 12-hr period. [ 125 I]AzIdUrd was phosphorylated by a cell free extract of H9 cells at a rate approximately three times that of thymidine and its phosphorylation was inhibited by excess thymidine. AzIdUrd was found to be a competitive inhibitor of cytosolic thymidine kinase with a K i , of 2.63 μM and AzIdUMP a weak competitive inhibitor of thymidylate kinase with a K i of 55.3 μM. Both AzIdUTP and AzBdUTP were potent competitive inhibitors of HIV-1 reverse transcriptase ( K i = 0.028 and 0.043 { rmmM , respectively) and relatively poors inhibitors of H9 cell DNA polymerase α( K i = 42.0 and 42.7 { rmmM , respectively). Thus, the high therapeutic index of these compounds is due to the sensitivity of the viral reverse transcriptase, coupled with the relative insensitivity of the host cell DNA polymerase α. |
| Databáze: | OpenAIRE |
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