title: Direct evidence for the covalent modification of glutathione-S-transferase P1-1 by electrophilic prostaglandins: implications for enzyme inactivation and cell survival.
abstract: Glutathione-S-transferases (GST) catalyze the conjugation of electrophilic compounds to glutathione, thus playing a key role in cell survival and tumor chemoresistance. Cyclopentenone prostaglandins (cyPG) are electrophilic eicosanoids that display potent antiproliferative properties, through multiple mechanisms not completely elucidated. Here we show that the cyPG 15-deoxy-Delta(12,14)-PGJ2 (15d-PGJ2) binds to GSTP1-1 covalently, as demonstrated by mass spectrometry and by the use of biotinylated 15d-PGJ2. Moreover, cyPG inactivate GSTP1-1 irreversibly. The presence of the cyclopentenone moiety is important for these effects. Covalent interactions also occur in cells, in which 15d-PGJ2 binds to endogenous GSTP1-1, irreversibly reduces GST free-thiol content and inhibits GST activity. Protein delivery of GSTP1-1 improves cell survival upon serum deprivation whereas 15d-PGJ2-treated GSTP1-1 displays a reduced protective effect. These results show the first evidence for the formation of stable adducts between cyPG and GSTP1-1 and may offer new perspectives for the development of irreversible GST inhibitors as anticancer agents.
authors.affiliation: Departamento de Estructura y Función de Proteínas, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Sánchez-Gómez
authors.forename: Javier
authors.initials: J
authors.lastname: Gayarre
authors.forename: M Isabel
authors.initials: MI
authors.lastname: Avellano
authors.forename: Dolores
authors.initials: D
authors.lastname: Pérez-Sala
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003517:Cyclopentanes / Q000737:chemistry; D004789:Enzyme Activation / Q000187:drug effects; D051549:Glutathione S-Transferase pi / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: C097240:15-deoxy-delta(12,14)-prostaglandin J2; D000970:Antineoplastic Agents; D003517:Cyclopentanes; D011994:Recombinant Proteins; D051549:Glutathione S-Transferase pi; C013905:cyclopentenone; D015230:Prostaglandin D2