title: Identification of toxin inhibitors using a magnetic nanosensor-based assay.
abstract: A magnetic nanosensor-based method is described to screen a library of drugs for potential binding to toxins. Screening is performed by measuring changes in the magnetic relaxation signal of the nanosensors (bMR nanosensors) in aqueous suspension upon addition of the toxin. The Anthrax lethal factor (ALF) is selected as a model toxin to test the ability of our bMR nanosensor-based screening method to identify potential inhibitors of the toxin. Out of 30 molecules screened, sulindac, naproxen and fusaric acid are found to bind LF, with dissociation constants in the low micromolar range. Further biological analysis of the free molecules in solution indicate that sulindac and its metabolic products inhibited LF cytotoxicity to macrophages with IC50 values in the micromolar range. Meanwhile, fusaric acid is found to be less effective at inhibiting LF cytotoxicity, while naproxen does not inhibit LF toxicity. Most importantly, when the sulindac and fusaric acid-bMR nanosensors themselves are tested as LF inhibitors, as opposed to the corresponding free molecules, they are stronger inhibitors of LF with IC50 values in the nanomolar range. Taken together, these studies show that a bMR nanosensors-based assay can be used to screen known drugs and other small molecules for inhibitor of toxins. The method can be easily modified to screen for inhibitors of other molecular interactions and not only the selected free molecule can be study as potential inhibitors but also the bMR nanosensors themselves achieving greater inhibitory potential.
authors: NanoScience Technology Center, 12424 Research Parway, Suite 400, University of Central Florida, Orlando, FL, 32826, USA; Department of Chemistry, 4111 Libra Drive, Physical Sciences Bld, Room 255, University of Central Florida, Orlando, FL, 32826, USA.
authors: Oscar J
authors: OJ
authors: Santiesteban
authors: Charalambos
authors: C
authors: Kaittanis
authors: J Manuel
authors: JM
authors: Perez
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial; D001427:Bacterial Toxins / Q000037:antagonists & inhibitors*; D001667:Binding, Competitive / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D003198:Computer Simulation; D005456:Fluorescent Dyes / Q000494:pharmacology; D005669:Fusaric Acid / Q000737:chemistry / Q000494:pharmacology; D008280:Magnetics / Q000295:instrumentation* / Q000379:methods*; D051379:Mice; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods*; D011480:Protease Inhibitors / Q000032:analysis / Q000494:pharmacology; D054852:Small Molecule Libraries / Q000032:analysis / Q000494:pharmacology; D013467:Sulindac / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D005456:Fluorescent Dyes; D011480:Protease Inhibitors; D054852:Small Molecule Libraries; C030325:anthrax toxin; D013467:Sulindac; D005669:Fusaric Acid
keywords: anthrax; drug repurposing; iron oxide; magnetic nanosensors; toxins