Antiretroviral Agents as Inhibitors of both Human Immunodeficiency Virus Type 1 Integrase and Protease

Abstract

The human immunodeficiency virus type one integrase (HIV-1 integrase) is required for integration of a double-stranded DNA copy of the viral RNA genome into a host chromosome and for HIV replication. We have previously reported that phenolic moieties in compounds such as flavones, caffeic acid phenethyl ester (CAPE), tyrphostins, and curcumin confer inhibitory activity against HIV-1 integrase. We have investigated the actions of several recently described protease inhibitors, possessing novel structural features, on HIV-1 integrase. NSC 158393, which contains four 4-hydroxycoumarin residues, was found to exhibit antiviral, antiprotease, and antiintegrase activity. Both the DNA binding and catalytic activities (3'-processing and strand transfer) of integrase were inhibited at micromolar concentrations. Disintegration catalyzed by an integrase mutant containing only the central catalytic domain was also inhibited, indicating that the binding site for these compounds resides in the central 50-212 amino acids of HIV-1 integrase. Binding at or near the integrase catalytic site was also suggested by a global inhibition of the choice of attacking nucleophile in the 3'-processing reaction. NSC 158393 inhibited HIV-2, feline, and simian immunodeficiency virus integrases while eukaryotic topoisomerase I was inhibited at higher concentrations, suggesting selective inhibition of retroviral integrases. Molecular modeling studies revealed that the two hydroxyls and two carbonyl moieties in NSC 158393 may represent essential elements of the pharmacophore. Antiviral efficacy was observed with NSC 158393 derivatives that inhibited both HIV protease and integrase, and the most potent integrase inhibitors also inhibited HIV protease. Hydroxycoumarins may provide lead compounds for development of novel antiviral agents based upon the concurrent inhibition of two viral targets, HIV-1 integrase and protease.

Discovery of a small-molecule HIV-1 integrase inhibitor-binding site

“…The catalytic core domain of IN was used for photo-crosslinking based on previous results demonstrating that hydroxycoumarins inhibit disintegration activity of the IN catalytic core domain (13). To form the protein-ligand complex, IN was incubated with a 25 molar excess of compound 3 at a final protein concentration of 1.3 ϫ 10 Ϫ5 M in a buffer containing 2.5 mM MnCl 2 , 50 mM 2-mercaptoethanol, 0.2% CHAPS, and 33% DMSO for 30 min at room temperature.…”

“…Previous catechol-containing IN inhibitors were highly cytotoxic, rendering therapeutic development impractical (12). Certain hydroxycoumarin analogues within this class also exhibit antiviral activity (13). Compound 1 inhibited IN at an IC 50 ϭ 1.5 M and inhibited disintegration activity of the catalytic core domain ) at a concentration of Ն15 M. This result provides evidence that compound 1 binds the catalytic core domain, and binding this region alone is responsible for inhibition activity.…”

“…Compound 1 inhibited IN at an IC 50 ϭ 1.5 M and inhibited disintegration activity of the catalytic core domain ) at a concentration of Ն15 M. This result provides evidence that compound 1 binds the catalytic core domain, and binding this region alone is responsible for inhibition activity. Compound 1 also exhibits antiviral activity (13). Subsequent structure-activity relationship (SAR) studies were performed to define the minimal chemical features of compound 1 required for inhibitory activity (14).…”

In vitro antimicrobial activity of a new series of 1,4-naphthoquinones

“…Antibacterial activity has been described for isoxazolylnaphthoquinones (10), and some hydroxyquinones and their metal complexes (11,12). The fungitoxicity of naphthoquinones (8), particularly against several species of Candida (13)(14)(15), and the inhibitory activity of some naphthoquinones on HIV-1 protease have also been described (16,17).…”

HIV-1 Integrase Inhibition of Biscoumarin Analogues

“…3,4) Recently numerous coumarin compounds have been evaluated for inhibitory effects against HIV replication, and some of them have been found to inhibit different stages in the HIV replication cycle. 5) A natural tetrameric coumarin (I) shown potent integrase inhibitory activity (IC 50 ϭ0.8 mM for integration and 1.5 mM for 3Ј-processing) was first reported by Mazumder et al 6) and the parent compound was then modified into simple components to determine the minimum active pharmacophore essential for potency. They disclosed a biscoumarin unit linked by a phenyl ring (II) was required for activity.…”