title: Glutathione influences c-Myc-induced apoptosis in M14 human melanoma cells.
abstract: The objective of this article is to dissect the mechanisms by which the down-regulation of c-Myc induces programmed cell death in melanoma cells. In stable and doxycycline-inducible M14 melanoma cells, down-regulation of c-Myc induced apoptosis subsequent to a decrease in the intracellular reduced glutathione content and a concomitant accumulation of its oxidized form. This redox alteration was associated with a decrease of the enzyme activities of gamma-glutamyl-cysteine synthetase and NADPH-dependent GSSG reductase, as well as a consequent glutathione release in the extracellular medium. Cytochrome c was released into the cytosol at very early stages of apoptosis induction, long before detectable production of reactive oxygen species and activation of caspase-9 and -3. Macroarray analysis revealed that down-regulation of c-Myc produced striking changes in gene expression in the section related to metabolism, where the expression of gamma-glutamyl-cysteine synthetase and GSSG reductase was found to be significantly reduced. The addition of N-acetyl-l-cysteine or glutathione ethyl ester inhibited the apoptotic process, thus confirming the key role of glutathione in programmed cell death induced by c-Myc.
authors.affiliation: Experimental Chemotherapy Laboratory, Regina Elena Cancer Institute, Via delle Messi d'Oro, 00158 Rome, Italy. biroccio@ifo.it
authors.forename: Annamaria
authors.initials: A
authors.lastname: Biroccio
authors.forename: Barbara
authors.initials: B
authors.lastname: Benassi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Filomeni
authors.forename: Sarah
authors.initials: S
authors.lastname: Amodei
authors.forename: Sergio
authors.initials: S
authors.lastname: Marchini
authors.forename: Giovanna
authors.initials: G
authors.lastname: Chiorino
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Rotilio
authors.forename: Gabriella
authors.initials: G
authors.lastname: Zupi
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Ciriolo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017209:Apoptosis; D015153:Blotting, Western; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D015536:Down-Regulation; D004318:Doxycycline / Q000494:pharmacology; D005434:Flow Cytometry; D005721:Glutamate-Cysteine Ligase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism* / Q000502:physiology; D005980:Glutathione Reductase; D006801:Humans; D008545:Melanoma / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D017382:Reactive Oxygen Species; D013880:Thioredoxin-Disulfide Reductase; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D000900:Anti-Bacterial Agents; D003574:Cytochrome c Group; D016271:Proto-Oncogene Proteins c-myc; D017382:Reactive Oxygen Species; D009247:NADH, NADPH Oxidoreductases; D005980:Glutathione Reductase; D013880:Thioredoxin-Disulfide Reductase; C424443:Txnrd3 protein, mouse; C505407:CASP3 protein, human; C506433:CASP9 protein, human; C505409:Casp3 protein, mouse; C506434:Casp9 protein, mouse; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione; D004318:Doxycycline