title: Targeting botulinum A cellular toxicity: a prodrug approach.
abstract: The botulinum neurotoxin light chain (LC) protease has become an important therapeutic target for postexposure treatment of botulism. Hydroxamic acid based small molecules have proven to be potent inhibitors of LC/A with nanomolar Ki values, yet they lack cellular activity conceivably due to low membrane permeability. To overcome this potential liability, we investigated two prodrug strategies, 1,4,2-dioxazole and carbamate, based on our 1-adamantylacetohydroxamic acid scaffold. The 1,4,2-dioxazole prodrug did not demonstrate cellular activity, however, carbamates exhibited cellular potency with the most active compound displaying an EC50 value of 20 μM. Cellular trafficking studies were conducted using a "fluorescently silent" prodrug that remained in this state until cellular uptake was complete, which allowed for visualization of the drug's release inside neuronal cells. In sum, this research sets the stage for future studies leveraging the specific targeting and delivery of these prodrugs, as well as other antibotulinum agents, into neuronal cells.
authors.affiliation: Departments of Chemistry and Immunology and Microbial Science, The Skaggs Institute for Chemical Biology, and The Worm Institute for Research and Medicine, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States.
authors.forename: Peter
authors.initials: P
authors.lastname: Silhár
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Eubanks
authors.forename: Hajime
authors.initials: H
authors.lastname: Seki
authors.forename: Sabine
authors.initials: S
authors.lastname: Pellett
authors.forename: Sacha
authors.initials: S
authors.lastname: Javor
authors.forename: William H
authors.initials: WH
authors.lastname: Tepp
authors.forename: Eric A
authors.initials: EA
authors.lastname: Johnson
authors.forename: Kim D
authors.initials: KD
authors.lastname: Janda
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology*; D001393:Azoles / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology; D019274:Botulinum Toxins, Type A / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002219:Carbamates / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003014:Clostridium botulinum / Q000187:drug effects / Q000378:metabolism; D004355:Drug Stability; D006207:Half-Life; D006801:Humans; D006877:Hydroxamic Acids / Q000737:chemistry; D018613:Microscopy, Confocal; D008956:Models, Chemical; D015394:Molecular Structure; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011355:Prodrugs / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001393:Azoles; D002219:Carbamates; D006877:Hydroxamic Acids; D011355:Prodrugs; D019274:Botulinum Toxins, Type A