RESUMEN
The illudin natural product family are fungal secondary metabolites with a characteristic spirocyclopropyl-substituted fused 6,5-bicyclic ring system. They have been extensively studied for their cytotoxicity in various tumor cell types, and semisynthetic derivatives with improved therapeutic characteristics have progressed to clinical trials. Although it is believed that this potent alkylating compound class acts mainly through DNA modification, little is known about its binding to protein sites in a cellular context. To reveal putative protein targets of the illudin family in live cancer cells, we employed a semisynthetic strategy to access a series of illudin-based probes for activity-based protein profiling (ABPP). While the probes largely retained potent cytotoxicity, proteomic profiling studies unraveled multiple protein hits, suggesting that illudins exert their mode of action not from addressing a specific protein target but rather from DNA modification and unselective protein binding.
Asunto(s)
Proteínas/química , Proteoma/química , Sesquiterpenos/farmacología , Compuestos de Espiro/farmacología , Células A549 , Alquilación , Antineoplásicos/química , Antineoplásicos/farmacología , Sitios de Unión , Supervivencia Celular , Humanos , Unión Proteica , Proteínas/metabolismo , Proteoma/metabolismo , Metabolismo Secundario , Sesquiterpenos/química , Compuestos de Espiro/químicaRESUMEN
Degrasyn inhibits deubiquitination enzymes and has anti-cancer activity. We here show that it also exhibits antimicrobial activity against multi-resistant Staphylococcus aureus. Structure activity relationship studies demonstrate an important role of the electrophilic α-cyanoacrylamide moiety as a Michael acceptor. A suite of chemical proteomic techniques unraveled binding of this moiety to various cysteine residues of essential proteins in a reversibly covalent manner.
Asunto(s)
Antibacterianos/farmacología , Cianoacrilatos/farmacología , Cisteína/química , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Piridinas/farmacología , Staphylococcus aureus/efectos de los fármacos , UbiquitinaciónRESUMEN
New drugs are desperately needed to combat methicillin-resistant Staphylococcus aureus (MRSA) infections. Here, we report screening commercial kinase inhibitors for antibacterial activity and found the anticancer drug sorafenib as major hit that effectively kills MRSA strains. Varying the key structural features led to the identification of a potent analogue, PK150, that showed antibacterial activity against several pathogenic strains at submicromolar concentrations. Furthermore, this antibiotic eliminated challenging persisters as well as established biofilms. PK150 holds promising therapeutic potential as it did not induce in vitro resistance, and shows oral bioavailability and in vivo efficacy. Analysis of the mode of action using chemical proteomics revealed several targets, which included interference with menaquinone biosynthesis by inhibiting demethylmenaquinone methyltransferase and the stimulation of protein secretion by altering the activity of signal peptidase IB. Reduced endogenous menaquinone levels along with enhanced levels of extracellular proteins of PK150-treated bacteria support this target hypothesis. The associated antibiotic effects, especially the lack of resistance development, probably stem from the compound's polypharmacology.