Design and Synthesis of Phosphonoacetic Acid (PPA) Ester and Amide Bioisosters of Ribofuranosylnucleoside Diphosphates as Potential Ribonucleotide Reductase Inhibitors and Evaluation of Their Enzyme Inhibitory, Cytostatic and Antiviral Activity
Stefano Manfredini, Nicola Solaroli, Angela Angusti, Federico Nalin, Elisa Durini, Silvia Vertuani, Sabrina Pricl, Marco Ferrone, Silvio Spadari, Federico Focher, Annalisa Verri, Erik De Clercq
(+1 others)
2003
Antiviral Chemistry & Chemotherapy
The ribonucleotide reductase (RNR) is a crucial enzyme in the de novo synthesis of DNA; it converts all ribonucleoside diphosphates (NDP) into the corresponding 2′-deoxyribonucleotides (dNDP) in prokaryotic and eukaryotic cells. Viral RNRs are also known: herpes simplex virus (HSV)and varicella zoster virus (VZV)-infected cells express a viral ribonucleotide reductase, distinct from that present in uninfected cells, which is endowed with a proper enzymatic activity that ensures sufficient
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... xynucleotide supply and DNA synthesis (Boehmer et al., 1997; Heineman et al., 1994) . Over the last decade, this enzyme has attracted increasing interest as an important target in the control of the replication of neoplastic cells as well as of pathogenic viral agents. The ribonucleotide diphosphate reductase (RDR) of the E. coli, mammalian and HSV, is structurally formed by two homodimeric proteins, namely R1 and R2, each of them is composed of two polypeptidic chains characterized by an α2β2 structure. The R1 subunit contains the binding sites for the ribonucleoside diphosphates, which are the specific substrates, and for the allosteric effectors, which control the speed and the specificity of dNDP formation. In previous studies, aimed at discovering new mechanism-based inhibitors of RNR , we pointed out the significant role of the diphosphate moiety of the nucleotide during the interaction with RNR. In fact, molecular modelling studies clearly showed that both natural and nucleoside diphosphate analogues accomplish their strong hydrogen bonds with Glu623, Continuing our investigations on inhibitors of ribonucleotide reductase (RNR) , the crucial enzyme that catalyses the reduction of ribonucleotides to deoxyribonucleotides, we have now prepared and evaluated 5'-phosphono acetic acid, amide and ester analogues of adenosine, uridine and cytidine with the aim to verify both substrate specificity and contribution to biological activity of diphosphate mimic moieties. A molecular modeling study has been conducted on the RNR R1 subunit, in order to verify the possible interaction of the proposed bioisosteric moieties. The study compounds were finally tested on the recombinant murine RNR showing a degree of inhibition that ranged from 350 µM for the UDP analogue 5'- deoxy-5'-N-(phosphon-acetyl)uridine sodium salt (amide) to 600 µM for the CDP analogue 5'-O-[(diethyl-phosphon)acetyl]cytidine (ester). None of the tested compounds displayed noteworthy cytostatic activity at 100-500 µM concentrations, whereas ADP analogue 5'-N-[(diethyl-phosphon) acetyl]adenosine (amide) and 5'-deoxy-5'-N-(phosphon-acetyl)adenosine sodium salt (amide) showed a moderate inhibitory activity (EC 50 : 48 µM) against HSV-2 and a modest inhibitory activity (EC 50 : 110 µM) against HIV-1, respectively.
doi:10.1177/095632020301400403
pmid:14582847
fatcat:iiincvsygbgrtcrahl25d2xfru
