Peptidomimetic inhibitors of herpes simplex virus ribonucleotide reductase: a new class of antiviral agents

Moss, Neil; Beaulieu, Pierre L.; Duceppe, Jean‐Simon; Ferland, Jean-Marie; Gauthier, Jean; Ghiro, Elsie; Goulet, Sylvie; Grenier, Louis; Llinàs‐Brunet, Montse; Plante, Raymond; Wernic, Dominik; Déziel, Robert

doi:10.1021/jm00018a022

Cited by 33 publications

(40 citation statements)

References 6 publications

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“…In vitro studies have shown that inhibitors of cellular RR or the HSV-1 or VZV RRs (including HU, FMdC, A723U, A1110U, BW348U87, and the “BILD” series of peptidomimetics) exhibit antiviral activity when used alone and either potentiate or result in synergy when used in combination with ACV against wild type or drug-resistant strains of VZV, HSV-1, or HSV-2 (Bridges et al, 1995; Duan et al, 1998; Ellis et al, 1989; Lawetz and Liuzzi, 1998; Liuzzi et al, 1994; Moss et al, 1996, 1995; Neyts and De Clercq, 1999; Prichard and Shipman, 1995; Sergerie and Boivin, 2008; Spector et al, 1985, 1987, 1989). HU has also been shown to potentiate the activity of cidofovir and to synergize with GCV to inhibit replication of wild type or drug-resistant strains of HSV-1 or HSV-2 (Neyts and De Clercq, 1999; Sergerie and Boivin, 2008).…”

Section: Discussionmentioning

confidence: 99%

Ribonucleotide reductase inhibitors hydroxyurea, didox, and trimidox inhibit human cytomegalovirus replication in vitro and synergize with ganciclovir

2013

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Ganciclovir (GCV) is a deoxyguanosine analog that is effective in inhibiting human cytomegalovirus (HCMV) replication. In infected cells GCV is converted to GCV-triphosphate which competes with dGTP for incorporation into the growing DNA strand by the viral DNA polymerase. Incorporated GCV promotes chain termination as it is an inefficient substrate for elongation. Because viral DNA synthesis also relies on cellular ribonucleotide reductase (RR) to synthesize deoxynucleotides, RR inhibitors are predicted to inhibit HCMV replication. Moreover, as dGTP competes with GCV-triphosphate for incorporation, RR inhibitors may also synergize with GCV by reducing intracellular dGTP levels and there by promoting increased GCV-triphosphate utilization by DNA polymerase. To investigate potential of RR inhibitors as anti-HCMV agents both alone and in combination with GCV, HCMV-inhibitory activities of three RR inhibitors, hydroxyurea, didox, and trimidox, were determined. In both spread inhibition and yield reduction assays RR inhibitors had modest anti-HCMV activity with 50% inhibitory concentrations ranging from 36 ± 1.7 to 221 ± 52 µM. However, all three showed significant synergy with GCV at concentrations below their 50% inhibitory and 50% toxic concentrations. These results suggest that combining GCV with relatively low doses of RR inhibitors could significantly potentiate the anti-HCMV activity of GCV in vivo and could improve clinical response to therapy.

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Section: Discussionmentioning

confidence: 99%

Ribonucleotide reductase inhibitors hydroxyurea, didox, and trimidox inhibit human cytomegalovirus replication in vitro and synergize with ganciclovir

2013

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“…Hence, C-terminal Rnr2-based peptidomimetics (14-16) bind Rnr1, blocking RNR assembly and providing another mode of therapy for proliferative diseases such as cancer. Early reports on Rnr2 peptide-based inhibitors showed that they had in vivo efficacy against herpes simplex virus with nM dissociation constants (17)(18)(19), suggesting that similar potencies might be possible with anticancer peptidomimetics.…”

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confidence: 99%

Structures of eukaryotic ribonucleotide reductase I define gemcitabine diphosphate binding and subunit assembly

Faber

Uchiki

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Ribonucleotide reductase (RNR) catalyzes the conversion of nucleoside diphosphates to deoxynucleoside diphosphates. Crucial for rapidly dividing cells, RNR is a target for cancer therapy. In eukaryotes, RNR comprises a heterooligomer of ␣2 and ␤2 subunits. Rnr1, the ␣ subunit, contains regulatory and catalytic sites; Rnr2, the ␤ subunit (in yeast, a heterodimer of Rnr2 and Rnr4), houses the diferric-tyrosyl radical crucial for catalysis. Here, we present three x-ray structures of eukaryotic Rnr1 from Saccharomyces cerevisiae: one bound to gemcitabine diphosphate (GemdP), the active metabolite of the mechanism-based chemotherapeutic agent gemcitabine; one with an Rnr2-derived peptide, and one with an Rnr4-derived peptide. Our structures reveal that GemdP binds differently from its analogue, cytidine diphosphate; because of unusual interactions of the geminal fluorines, the ribose and base of GemdP shift substantially, and loop 2, which mediates substrate specificity, adopts different conformations when binding to GemdP and cytidine diphosphate. The Rnr2 and Rnr4 peptides, which block RNR assembly, bind differently from each other but have unique modes of binding not seen in prokaryotic RNR. The Rnr2 peptide adopts a conformation similar to that previously reported from an NMR study for a mouse Rnr2-based peptide. In yeast, the Rnr2 peptide binds at subsites consisting of residues that are highly conserved among yeast, mouse, and human Rnr1s, suggesting that the mode of Rnr1-Rnr2 binding is conserved among eukaryotes. These structures provide new insights into subunit assembly and a framework for structure-based drug design targeting RNR.allosteric regulation ͉ crystallography ͉ dNTP ͉ chemotherapy ͉ gemcitabine R ibonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides to deoxyribonucleotides, essential precursors of DNA synthesis. Crucial for rapidly proliferating cells, RNR is a target for anticancer (1, 2) and antiviral (2, 3) drugs. Gemcitabine, an analogue of deoxycytidine (2Ј-2Ј-difluorodeoxycytidine), is sequentially phosphorylated to the 5Ј-monophosphate form by deoxycytidine kinase and to difluorodeoxycytidine 5Ј-diphosphate (GemdP) by uridylate-cytidylate monophosphate kinase. In the presence of reductants, GemdP inactivates Rnr1. In the absence of reductants, with prereduced Rnr1 and Rnr2, inhibition occurs from the loss of the tyrosyl radical in Rnr2 (1). Recently, GemdP has been shown to inactivate both human R1 and R2 (JoAnne Stubbe, personal communication). Inhibition of RNR by GemdP leads to reduction of the pool of deoxyribonucleotide 5Ј-diphosphates available for DNA synthesis, presumably favoring incorporation of the gemcitabine triphosphate metabolite by DNA polymerase ␣, preventing chain elongation (4, 5).RNRs require unusual metallocofactors to initiate radicalbased nucleotide reduction and are divided into three classes based on their cofactor. Class I RNR, found in all eukaryotes, is a heterooligomer of ␣ 2 and ␤ 2 subunits (6). In eukaryotes, the ␣ subunit, called Rnr1, c...

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“…However, replacement of the acetyl group in compound 2 with a 3-phenylpropionyl group (compound 3) increased binding potency over 30 times. 11 Compound 3 provided the starting point for structure-activity studies that led to the discovery of ribonucleotide reductase inhibitors effective at preventing HSV replication in vitro and in vivo. 5 The binding potency increase associated with the 3-phenylpropionyl group (illustrated by compound 3) and related derivatives proved to be very important for inhibitor antiviral activity.…”

Section: Resultsmentioning

confidence: 99%

“…5000-fold. 11 As it was evident that a lipophilic group at this position was essential for good inhibitor potency, we speculated that the N-terminal NH in compound 4 might serve to more favorably position the lipophilic group for binding to R1. However, sequential truncation of the (ethylpropyl)amino group in 4 to a methyl group (compounds 5 and 6) culminated in a 2800-fold loss of potency.…”

Section: Resultsmentioning

confidence: 99%

Ureido-Based Peptidomimetic Inhibitors of Herpes Simplex Virus Ribonucleotide Reductase: An Investigation of Inhibitor Bioactive Conformation

et al. 1996

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We have been investigating peptidomimetic inhibitors of herpes simplex virus (HSV) ribonucleotide reductase (RR). These inhibitors bind to the HSV RR large subunit and consequently prevent subunit association and subsequent enzymatic activity. This report introduces a new series of compounds that contain an extra nitrogen (a ureido function) at the inhibitor N-terminus. This nitrogen improves inhibitor binding potency 50-fold over our first published inhibitor series. Evidence supports that this improvement in potency results from a new hydrogen-bonding contact between the inhibitor and the RR large subunit. This report also provides evidence for the bioactive conformation around two important amino acid residues contained in our inhibitors. A tert-butyl group, which contributes 100-fold to inhibitor potency but does not directly bind to the large subunit, favors an extended beta-strand conformation that is prevalent in solution and in the bound state. More significantly, the bioactive conformation around a pyrrolidine-modified asparagine residue, which contributes over 30 000-fold to inhibitor potency, is elucidated through a series of conformationally restricted analogues.

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Peptidomimetic inhibitors of herpes simplex virus ribonucleotide reductase: a new class of antiviral agents

Cited by 33 publications

References 6 publications

Ribonucleotide reductase inhibitors hydroxyurea, didox, and trimidox inhibit human cytomegalovirus replication in vitro and synergize with ganciclovir

Ribonucleotide reductase inhibitors hydroxyurea, didox, and trimidox inhibit human cytomegalovirus replication in vitro and synergize with ganciclovir

Structures of eukaryotic ribonucleotide reductase I define gemcitabine diphosphate binding and subunit assembly

Ureido-Based Peptidomimetic Inhibitors of Herpes Simplex Virus Ribonucleotide Reductase: An Investigation of Inhibitor Bioactive Conformation

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