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

A series of 13 acyclic nucleoside phosphonates (ANPs) as bisamidate prodrugs was prepared. Five compounds were found to be non-cytotoxic and selective inhibitors of Bordetella pertussis adenylate cyclase toxin (ACT) in J774A.1 macrophage cell-based assays. The 8-aza-7-deazapurine derivative of adefovir (PMEA) was found to be the most potent ACT inhibitor in the series (IC50 =16 nm) with substantial selectivity over mammalian adenylate cyclases (mACs). AC inhibitory properties of the most potent analogues were confirmed by direct evaluation of the corresponding phosphonodiphosphates in cell-free assays and were found to be potent inhibitors of both ACT and edema factor (EF) from Bacillus anthracis (IC50 values ranging from 0.5 to 21 nm). Moreover, 7-halo-7-deazapurine analogues of PMEA were discovered to be potent and selective mammalian AC1 inhibitors (no inhibition of AC2 and AC5) with IC50 values ranging from 4.1 to 5.6 μm in HEK293 cell-based assays.

• Keywords
• Bacillus anthracis, Bordetella pertussis, adefovir, adenylate cyclase, inhibitors,
• MeSH
• Adenine analogs & derivatives   chemical synthesis   chemistry   pharmacology   MeSH
• Adenylyl Cyclases metabolism   MeSH
• Bacillus anthracis enzymology   MeSH
• Bordetella pertussis enzymology   MeSH
• Enzyme Inhibitors chemical synthesis   chemistry   pharmacology   MeSH
• Molecular Structure MeSH
• Organophosphonates 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
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• adefovir MeSH Browser
• Adenine MeSH
• Adenylyl Cyclases MeSH
• Enzyme Inhibitors MeSH
• Organophosphonates MeSH