Structure-activity and cross-resistance evaluations of a series of human immunodeficiency virus type-1-specific compounds related to oxathiin carboxanilide

Abstract

A series of compounds related to the nonnucleoside reverse transcriptase (RT) inhibitor (NNRTI) oxathiin carboxanilide (UC84) were evaluated for activity against the human immunodeficiency virus (HIV) to determine structural requirements for anti-HIV activity. Twenty-seven compounds representative of the more than 400 Uniroyal Chemical Company (UC) compounds were evaluated for structure-activity relationships. Several of the compounds evaluated were highly active, with 50% effective concentrations in the nanomolar range and therapeutic indices of >1,000. Highly synergistic anti-HIV activity was observed for each compound when used in combination with 3-azido-3-deoxythymidine; additive to slightly synergistic interactions were observed with the compounds used in combination with dideoxycytidine. In combination with the NNRTI costatolide, only UC38 synergistically inhibited HIV type 1. Residues in the RT which, when mutated, impart resistance to the carboxanilide compounds were defined by evaluation of the UC compounds against a panel of NNRTI-resistant virus isolates selected in cell culture, against virus variants with site-directed mutations, and against RTs containing defined single amino acid changes. The mutations included changes in RT amino acids 100, 101, 103, 106, 108, and 181. The results with isolates selected in cell culture indicate that the carboxanilide compounds interact with the RT at two vulnerable sites, selecting UC-resistant virus isolates with the Y-to-C mutation at position 181 (Y181C) or the L100I substitution. A resistant virus isolate containing both Y181C and K101E amino acid changes and another with both Y181C and V106A mutations were isolated. In combination with calanolide A, an NNRTI which retains activity against virus isolates with the single Y181C mutation, UC10 rapidly selected a virus isolate with the K103N mutation. The merits of selecting potential candidate anti-HIV agents to be used in rational combination drug design as part of an armamentarium of highly active anti-HIV compounds are discussed.

Shikonin, a Component of Chinese Herbal Medicine, Inhibits Chemokine Receptor Function and Suppresses Human Immunodeficiency Virus Type 1

“…All experiments for antiviral activity were performed with triplicate samples in RPMI 1640 medium supplemented with 15% fetal bovine serum, L-glutamate (2 mM), penicillin (100 U/ml), and streptomycin (100 g/ml). HIV-1 replication in PBMC and monocyte/macrophage cultures was determined by measurement of the RT activity in the supernatant and p24 antigen expression, respectively, by enzymelinked immunosorbent assay (Coulter, Hialeah, Fla.) (2,3). Cell viability was determined by measurement of formazan dye reduction in replicate cultures in CellTiter reagent (Promega, Madison, Wis.).…”

Non-nucleoside Inhibitors of HIV-1 Reverse Transcriptase Inhibit Phosphorolysis and Resensitize the 3′-Azido-3′-deoxythymidine (AZT)-resistant Polymerase to AZT-5′-triphosphate

“…Because both groups of inhibitors bind to different sites on RT in a nonexclusive manner (12), combinations of nucleoside analogs and non-nucleoside inhibitors might have a potential synergistic inhibitory effect on HIV-1 RT. Synergistic inhibition of HIV replication in cell culture has been reported for many combinations of nucleoside and non-nucleoside RT inhibitors (13)(14)(15)(16). Nevertheless, several other studies have shown that the same combinations showed no synergy in inhibiting RT activity in vitro (17)(18)(19)(20)(21).…”

Potent Anti-Influenza Activity of Cyanovirin-N and Interactions with Viral Hemagglutinin

“…Antiviral bioassays. CV-N and its functional homologs were evaluated against a range of virus isolates by standardized cytopathic effect (CPE) inhibition assays (9) or specific antiviral assays as specified in Tables 1 and 2. In all assays the cytotoxic effects of compounds were measured spectrometrically by formazan dye reduction using either XXT {2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide} or MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt] (CellTiter 96; Promega, Madison, Wis.).…”