title: Disulfiram-induced cytotoxicity and endo-lysosomal sequestration of zinc in breast cancer cells.
abstract: Disulfiram, a clinically used alcohol-deterrent has gained prominence as a potential anti-cancer agent due to its impact on copper-dependent processes. Few studies have investigated zinc effects on disulfiram action, despite it having high affinity for this metal. Here we studied the cytotoxic effects of disulfiram in breast cancer cells, and its relationship with both intra and extracellular zinc. MCF-7 and BT474 cancer cell lines gave a striking time-dependent biphasic cytotoxic response between 0.01 and 10 μM disulfiram. Co-incubation of disulfiram with low-level zinc removed this effect, suggesting that availability of extracellular zinc significantly influences disulfiram efficacy. Live-cell confocal microscopy using fluorescent endocytic probes and the zinc dye Fluozin-3 revealed that disulfiram selectively and rapidly increased zinc levels in endo-lysosomes. Disulfiram also caused spatial disorganization of late endosomes and lysosomes, suggesting they are novel targets for this drug. This relationship between disulfiram toxicity and ionophore activity was consolidated via synthesis of a new disulfiram analog and overall we demonstrate a novel mechanism of disulfiram-cytotoxicity with significant clinical implications for future use as a cancer therapeutic.
authors.affiliation: Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, Cardiff, Wales CF10 3NB, UK.
authors.forename: Helen L
authors.initials: HL
authors.lastname: Wiggins
authors.affiliation: Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, Cardiff, Wales CF10 3NB, UK.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Wymant
authors.affiliation: Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, Cardiff, Wales CF10 3NB, UK.
authors.forename: Francesca
authors.initials: F
authors.lastname: Solfa
authors.affiliation: Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, Cardiff, Wales CF10 3NB, UK.
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Hiscox
authors.affiliation: Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, Cardiff, Wales CF10 3NB, UK.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Taylor
authors.affiliation: Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, Cardiff, Wales CF10 3NB, UK.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Westwell
authors.affiliation: Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, Cardiff, Wales CF10 3NB, UK. Electronic address: jonesat@cardiff.ac.uk.
authors.forename: Arwyn T
authors.initials: AT
authors.lastname: Jones
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D003603:Cytotoxins / Q000494:pharmacology* / Q000627:therapeutic use; D004221:Disulfiram / Q000494:pharmacology* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism*; D061986:MCF-7 Cells; D015032:Zinc / Q000378:metabolism*
chemical_list: D003603:Cytotoxins; D015032:Zinc; D004221:Disulfiram
keywords: Breast cancer; Disulfiram; Fluozin-3; Lysosomes; Zinc