Adefovir based acyclic nucleoside phosphonates were previously shown to modulate bacterial and, to a certain extent, human adenylate cyclases (mACs). In this work, a series of 24 novel 7-substituted 7-deazaadefovir analogues were synthesized in the form of prodrugs. Twelve analogues were single-digit micromolar inhibitors of Bordetella pertussis adenylate cyclase toxin with no cytotoxicity to J774A.1 macrophages. In HEK293 cell-based assays, compound 14 was identified as a potent (IC50 = 4.45 μM), non-toxic, and selective mAC2 inhibitor (vs. mAC1 and mAC5). Such a compound represents a valuable addition to a limited number of small-molecule probes to study the biological functions of individual endogenous mAC isoforms.

• Keywords
• 7-Deazapurine, Acyclic nucleoside phosphonates, Adefovir, Adenylate cyclase, Prodrugs,
• MeSH
• Adenylate Cyclase Toxin MeSH
• Adenylyl Cyclases * MeSH
• HEK293 Cells MeSH
• Humans MeSH
• Nucleosides chemistry   MeSH
• Organophosphonates * pharmacology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• 7-deazapurine MeSH Browser
• adefovir MeSH Browser
• Adenylate Cyclase Toxin MeSH
• Adenylyl Cyclases * MeSH
• Nucleosides MeSH
• Organophosphonates * MeSH

Compounds with a phosphonate group, i.e., -P(O)(OH)2 group attached directly to the molecule via a P-C bond serve as suitable non-hydrolyzable phosphate mimics in various biomedical applications. In principle, they often inhibit enzymes utilizing various phosphates as substrates. In this review we focus mainly on biologically active phosphonates that originated from our institute (Institute of Organic Chemistry and Biochemistry in Prague); i.e., acyclic nucleoside phosphonates (ANPs, e.g., adefovir, tenofovir, and cidofovir) and derivatives of non-nucleoside phosphonates such as 2-(phosphonomethyl) pentanedioic acid (2-PMPA). Principal strategies of their syntheses and modifications to prodrugs is reported. Besides clinically used ANP antivirals, a special attention is paid to new biologically active molecules with respect to emerging infections and arising resistance of many pathogens against standard treatments. These new structures include 2,4-diamino-6-[2-(phosphonomethoxy)ethoxy]pyrimidines or so-called "open-ring" derivatives, acyclic nucleoside phosphonates with 5-azacytosine as a base moiety, side-chain fluorinated ANPs, aza/deazapurine ANPs. When transformed into an appropriate prodrug by derivatizing their charged functionalities, all these compounds show promising potential to become drug candidates for the treatment of viral infections. ANP prodrugs with suitable pharmacokinetics include amino acid phosphoramidates, pivaloyloxymethyl (POM) and isopropoxycarbonyloxymethyl (POC) esters, alkyl and alkoxyalkyl esters, salicylic esters, (methyl-2-oxo-1,3-dioxol-4-yl) methyl (ODOL) esters and peptidomimetic prodrugs. We also focus on the story of cytostatics related to 9-[2-(phosphonomethoxy)ethyl]guanine and its prodrugs which eventually led to development of the veterinary drug rabacfosadine. Various new ANP structures are also currently investigated as antiparasitics, especially antimalarial agents e.g., guanine and hypoxanthine derivatives with 2-(phosphonoethoxy)ethyl moiety, their thia-analogues and N-branched derivatives. In addition to ANPs and their analogs, we also describe prodrugs of 2-(phosphonomethyl)pentanedioic acid (2-PMPA), a potent inhibitor of the enzyme glutamate carboxypeptidase II (GCPII), also known as prostate-specific membrane antigen (PSMA). Glutamate carboxypeptidase II inhibitors, including 2-PMPA have been found efficacious in various preclinical models of neurological disorders which are caused by glutamatergic excitotoxicity. Unfortunately its highly polar character and hence low bioavailability severely limits its potential for clinical use. To overcome this problem, various prodrug strategies have been used to mask carboxylates and/or phosphonate functionalities with pivaloyloxymethyl, POC, ODOL and alkyl esters. Chemistry and biological characterization led to identification of prodrugs with 44-80 fold greater oral bioavailability (tetra-ODOL-2-PMPA).

• Keywords
• 2-PMPA, FOLH1, GCPII, acyclic nucleoside phosphonates, antivirals, prodrugs, prostate-specific membrane antigen, protides,
• Publication type
• Journal Article MeSH
• Review MeSH

A series of acyclic nucleoside phosphonates (ANPs) was designed as inhibitors of bacterial adenylate cyclases (ACs), where adenine was replaced with 2-amino-4-arylthiazoles. The target compounds were prepared using the halogen dance reaction. Final AC inhibitors were evaluated in cell-based assays (prodrugs) and cell-free assays (phosphono diphosphates). Novel ANPs were potent inhibitors of adenylate cyclase toxin (ACT) from Bordetella pertussis and edema factor (EF) from Bacillus anthracis, with substantial selectivity over mammalian enzymes AC1, AC2, and AC5. Six of the new ANPs were more potent or equipotent ACT inhibitors (IC50 =9-18 nM), and one of them was more potent EF inhibitor (IC50 =12 nM), compared to adefovir diphosphate (PMEApp) with IC50 =18 nM for ACT and IC50 =36 nM for EF. Thus, these compounds represent the most potent ACT/EF inhibitors based on ANPs reported to date. The potency of the phosphonodiamidates to inhibit ACT activity in J774A.1 macrophage cells was somewhat weaker, where the most potent derivative had IC50 =490 nM compared to IC50 =150 nM of the analogous adefovir phosphonodiamidate. The results suggest that more efficient type of phosphonate prodrugs would be desirable to increase concentrations of the ANP-based active species in the cells in order to proceed with the development of ANPs as potential antitoxin therapeutics.

• Keywords
• Acyclic nucleoside phosphonates, Adenylate cyclase, Bordetella pertussis, Inhibitors, Prodrugs,
• MeSH
• Adenylate Cyclase Toxin antagonists & inhibitors   metabolism   MeSH
• Antigens, Bacterial metabolism   MeSH
• Bacillus anthracis chemistry   MeSH
• Bacterial Toxins antagonists & inhibitors   metabolism   MeSH
• Bordetella pertussis enzymology   MeSH
• Halogens chemistry   pharmacology   MeSH
• Adenylyl Cyclase Inhibitors chemical synthesis   chemistry   pharmacology   MeSH
• Molecular Structure MeSH
• Organophosphonates chemistry   pharmacology   MeSH
• Thiazoles chemical synthesis   chemistry   pharmacology   MeSH
• Dose-Response Relationship, Drug MeSH
• Structure-Activity Relationship MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• 2-aminothiazole MeSH Browser
• Adenylate Cyclase Toxin MeSH
• anthrax toxin MeSH Browser
• Antigens, Bacterial MeSH
• Bacterial Toxins MeSH
• Halogens MeSH
• Adenylyl Cyclase Inhibitors MeSH
• Organophosphonates MeSH
• Thiazoles MeSH

A series of novel acyclic nucleoside phosphonates (ANPs) was synthesized as potential adenylate cyclase inhibitors, where the adenine nucleobase of adefovir (PMEA) was replaced with a 5-substituted 2-aminothiazole moiety. The design was based on the structure of MB05032, a potent and selective inhibitor of fructose 1,6-bisphosphatase and a good mimic of adenosine monophosphate (AMP). From the series of eighteen novel ANPs, which were prepared as phosphoroamidate prodrugs, fourteen compounds were potent (single digit micromolar or submicromolar) inhibitors of Bordetella pertussis adenylate cyclase toxin (ACT), mostly without observed cytotoxicity in J774A.1 macrophage cells. Selected phosphono diphosphates (nucleoside triphosphate analogues) were potent inhibitors of ACT (IC50 as low as 37 nM) and B. anthracis edema factor (IC50 as low as 235 nM) in enzymatic assays. Furthermore, several ANPs were found to be selective mammalian AC1 inhibitors in HEK293 cell-based assays (although with some associated cytotoxicity) and one compound exhibited selective inhibition of mammalian AC2 (only 12% of remaining adenylate cyclase activity) but no observed cytotoxicity. The mammalian AC1 inhibitors may represent potential leads in development of agents for treatment of human inflammatory and neuropathic pain.

• Keywords
• Acyclic nucleoside phosphonates, Adefovir, Adenylate cyclase, Bacillus anthracis, Bordetella pertussis, Inhibitors, Prodrugs,
• MeSH
• Adenylate Cyclase Toxin antagonists & inhibitors   metabolism   MeSH
• Anti-Bacterial Agents chemical synthesis   chemistry   pharmacology   MeSH
• Bacillus anthracis drug effects   MeSH
• Bordetella pertussis drug effects   enzymology   MeSH
• Cell Line MeSH
• Adenylyl Cyclase Inhibitors chemical synthesis   chemistry   pharmacology   MeSH
• Humans MeSH
• Microbial Sensitivity Tests MeSH
• Molecular Structure MeSH
• Mice MeSH
• Neuralgia drug therapy   MeSH
• Organophosphonates chemistry   pharmacology   MeSH
• Thiazoles chemistry   pharmacology   MeSH
• Dose-Response Relationship, Drug MeSH
• Structure-Activity Relationship MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• 2-aminothiazole MeSH Browser
• Adenylate Cyclase Toxin MeSH
• Anti-Bacterial Agents MeSH
• Adenylyl Cyclase Inhibitors MeSH
• Organophosphonates MeSH
• Thiazoles MeSH