Metabolism of 9-(1,3-dihydroxy-2-propoxymethyl)guanine, a new anti-herpes virus compound, in herpes simplex virus-infected cells

Mise en évidence de la phosphorylation du 9-(1,3-dihydroxypropoxyméthyl)guanine (DHPG) conduisant à la formation d'un DHPGTP et à l'incorporation de cet analogue de nucléoside dans l'ADN

In vitro selection and molecular characterization of human immunodeficiency virus-1 resistant to non-nucleoside inhibitors of Reverse Transcriptase

Several newly discovered potent and selective non-nucleoside inhibitors of human immunodeficiency virus-1 reverse transcriptase (RT) are undergoing evaluation in clinical trials. We studied the potential for development of viral resistance to one of the prototype compounds, BI-RG-587, a dipyridodiazepinone derivative. Human immunodeficiency virus-1 resistant to BI-RG-587 emerged after only one cycle of in vitro infection in the presence of the drug. Resistant virus was cross-resistant to the non-nucleoside tetrahydroimidazo[4,5,1-jk][1,4]benzodiazepin-2(1H)-thione derivative R82150 but remained susceptible to 2',3'-dideoxynucleosides and phosphonoformate. Both native (virion-associated) and recombinant RT derived from resistant virus were insensitive to BI-RG-587 and R82150. Nucleotide sequence analysis of multiple drug-resistant and -sensitive recombinant RT clones identified a single predicted amino acid change common to all resistant clones (tyrosine-181----cysteine). These studies suggest that the viral resistance to non-nucleoside RT inhibitors may develop in vivo. This possibility should be carefully monitored in clinical trials of these compounds

Inhibition of HIV-1 Ribonuclease H activity by novel frangula-emodine derivatives

The HIV-1 reverse transcriptase (RT) associated ribonuclease H (RNase H) activity hydrolyzes the RNA component of the viral heteroduplex RNA:DNA replication intermediate. Even though this function is essential for viral replication, until now only very few compounds have been reported to inhibit it. Anthraquinones are common secondary metabolites which have diverse biological activities. In particular, some of them have been reported to inhibit the HIV-1 RT polymerase and integrase activities in biochemical assays. Given the structural similarities between integrase and RNase H proteins, we synthesized a series of frangula-emodine derivatives and showed that the introduction of a bromine atom in position 7 of the anthraquinone structure leads to derivatives which are able to inhibit both HIV-1 polymerase and RNase H functions at micromolar concentrations. Mechanism of action studies performed on the 7-brom-6-O-phenacyl-1,8-dihydroxy-3-methyl anthraquinone (K67) showed that this compound is a non-competitive inhibitor of the RNase H function and that it binds to a site which is not overlapping to the non-nucleoside RT inhibitors binding site. This study demonstrates that anthraquinone derivatives may be a scaffold to be further developed to obtain selective HIV-1 RNase H inhibitors and represent a new step toward the identification of new anti-RT agents

Unique spectrum of activity of 9-[(1,3-dihydroxy-2-propoxy)methyl]-guanine against herpesviruses in vitro and its mode of action against herpes simplex virus type 1.

A guanosine analog, 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (DHPG), was found to inhibit herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2, cytomegalovirus, and Epstein-Barr virus replication by greater than 50% at concentrations that do not inhibit cell growth in culture. The potency of the drug against all of these viruses is greater than that of 9-[(2-hydroxyethoxy)methyl]guanine (acyclovir). DHPG was active against HSV-1 growth during the early phase of virus replication and had no activity when added at a later time after infection. Its antiviral activity was irreversible. Thymidine partially neutralized its action. The anti-HSV-1 activity of DHPG was dependent on the induction and the properties of virus-induced thymidine kinase. Virus variants that induced altered virus thymidine kinase and became resistant to acyclovir were still as sensitive to DHPG as the parental virus. DHPG is active against five different HSV variants with induced altered DNA polymerase and resistance to acyclovir

Demonstration of viral thymidine kinase inhibitor and its effect on deoxynucleotide metabolism in cells infected with herpes simplex virus.

The thymidine analog 5'-ethynylthymidine was a potent inhibitor of herpes simplex virus type 1 (strain KOS)-induced thymidine kinase with a Ki value of 0.09 microM. 5'-Ethynylthymidine was less inhibitory against herpes simplex virus type 2 (strain 333)-induced thymidine kinase with a Ki of 0.38 microM and showed no inhibition against human cytosolic thymidine kinase under the conditions tested. The compound was effective against the altered thymidine kinase induced by acyclovir- and bromovinyldeoxyuridine-resistant virus variants. At 100 microM 5'-ethynylthymidine, the cellular pool size of dTTP in herpes simplex virus type 1-infected cells was 5% that of infected cells receiving no drug treatment, while there was no significant effect on the pool sizes of dATP, dGTP, and dCTP. There was a positive correlation between dTTP pools and the intracellular thymidine kinase activity of herpes simplex virus type 1-infected cells. When tested alone, 5'-ethynylthymidine exhibited no antiviral activity, but it antagonized the antiviral efficacy of five compounds which require viral thymidine kinase for their action