ABSTRACT
Missense mutations in p53 are severely deleterious and occur in over 50% of all human cancers. The majority of these mutations are located in the inherently unstable DNA-binding domain (DBD), many of which destabilize the domain further and expose its aggregation-prone hydrophobic core, prompting self-assembly of mutant p53 into inactive cytosolic amyloid-like aggregates. Screening an oligopyridylamide library, previously shown to inhibit amyloid formation associated with Alzheimer's disease and type II diabetes, identified a tripyridylamide, ADH-6, that abrogates self-assembly of the aggregation-nucleating subdomain of mutant p53 DBD. Moreover, ADH-6 targets and dissociates mutant p53 aggregates in human cancer cells, which restores p53's transcriptional activity, leading to cell cycle arrest and apoptosis. Notably, ADH-6 treatment effectively shrinks xenografts harboring mutant p53, while exhibiting no toxicity to healthy tissue, thereby substantially prolonging survival. This study demonstrates the successful application of a bona fide small-molecule amyloid inhibitor as a potent anticancer agent.
Subject(s)
Amyloid/antagonists & inhibitors , Antineoplastic Agents/pharmacology , Protein Aggregation, Pathological/metabolism , Tumor Suppressor Protein p53/metabolism , Amides/chemistry , Amides/pharmacology , Amides/therapeutic use , Amyloid/chemistry , Amyloid/metabolism , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/therapeutic use , Apoptosis/drug effects , Cell Cycle/drug effects , Cell Line, Tumor , Humans , Mice , Mutation , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/genetics , Neoplasms, Experimental/metabolism , Protein Aggregation, Pathological/drug therapy , Protein Domains , Pyridines/chemistry , Pyridines/pharmacology , Pyridines/therapeutic use , Transcription, Genetic/drug effects , Tumor Suppressor Protein p53/chemistry , Tumor Suppressor Protein p53/geneticsABSTRACT
Membrane-catalysed misfolding of islet amyloid polypeptide is associated with the death of ß-cells in type II diabetes (T2D). Most active compounds so far reported require high doses for inhibition of membrane bound IAPP fibrillation. Here, we describe a naphthalimide-appended oligopyridylamide-based α-helical mimetic, DM 1, for targeting membrane bound IAPP. DM 1 completely inhibits the aggregation of IAPP at doses of 0.2 equivalents. DM 1 is also effective at similarly low doses for inhibition of seed-catalyzed secondary nucleation. An NMR based study demonstrates that DM 1 modulates IAPP self-assembly by stabilizing and/or perturbing the N-terminus helix conformation. DM 1 at substoichiometric doses rescues rat insulinoma cells from IAPP-mediated cytotoxicity. Most importantly, 0.2 equivalents of DM 1 disaggregate preformed oligomers and fibrils and can reverse cytotoxicity by modulating toxic preformed oligomers and fibrils of IAPP into non-toxic conformations.
