title: Induction of apoptosis without redox catastrophe by thioredoxin-inhibitory compounds.
abstract: The dithiol-reducing thioredoxin/thioredoxin reductase system normally maintains the reduced state of key enzymes responsible for the cell's anti-oxidant defences. We therefore addressed the question of whether AW 464--a novel thioredoxin inhibitor--as well as broad spectrum dithiol ligands diamide and phenylarsine oxide are able to induce and execute a regular apoptotic sequence of events without overwhelming the cell's ability to detoxify reactive oxygen species. All three agents were found to target the thioredoxin system in a cell-free assay. In HL-60 leukaemia cells, they were also found to induce Bak activation, cytochrome c release from mitochondria, decreasing Delta Psi m, chromatin condensation, phosphatidyl serine exposure and Tdt-sensitive DNA nicks. At the onset of apoptosis there was no evidence of increases in oxygen free radicals or peroxide in cells treated with AW 464 or diamide. Phenylarsine oxide induced both free radicals and hydrogen peroxide, but this did not appear to interfere with apoptosis. We conclude that pharmacological targeting of thioredoxin can induce a well-orchestrated apoptotic programme.
authors.affiliation: Division of Haematology, Nottingham City Hospital, University of Nottingham, Nottingham NG5 1PB, UK. monica.pallis@nottingham.ac.uk
authors.forename: Monica
authors.initials: M
authors.lastname: Pallis
authors.forename: Tracey D
authors.initials: TD
authors.lastname: Bradshaw
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Westwell
authors.forename: Martin
authors.initials: M
authors.lastname: Grundy
authors.forename: Malcolm F G
authors.initials: MF
authors.lastname: Stevens
authors.forename: Nigel
authors.initials: N
authors.lastname: Russell
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis; D001152:Arsenicals / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D003958:Diamide / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018922:HL-60 Cells; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010084:Oxidation-Reduction; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013879:Thioredoxins / Q000037:antagonists & inhibitors*; D050998:bcl-2 Homologous Antagonist-Killer Protein
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D000975:Antioxidants; D001152:Arsenicals; C494772:BAK1 protein, human; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D013439:Sulfhydryl Reagents; D050998:bcl-2 Homologous Antagonist-Killer Protein; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C029341:oxophenylarsine; D003958:Diamide; D013879:Thioredoxins; D020169:Caspases