title: Cyclopentenone prostaglandins of the J series inhibit the ubiquitin isopeptidase activity of the proteasome pathway.
abstract: Electrophilic eicosanoids of the J series, with their distinctive cross-conjugated alpha,beta-unsaturated ketone, inactivate genetically wild type tumor suppressor p53 in a manner analogous to prostaglandins of the A series. Like the prostaglandins of the A series, prostaglandins of the J series have a structural determinant (endocyclic cyclopentenone) that confers the ability to impair the conformation, the phosphorylation, and the transcriptional activity of the p53 tumor suppressor with equivalent potency and efficacy. However, J series prostaglandins have a unique structural determinant (exocyclic alpha,beta-unsaturated ketone) that confers unique efficacy as an apoptotic agonist. In seeking to understand how J series prostaglandins cause apoptosis despite their inactivation of p53, we discovered that they inhibit the ubiquitin isopeptidase activity of the proteasome pathway. In this regard, J series prostaglandins were more efficacious inhibitors than representative members of the A, B, or E series prostaglandins. Disruption of the proteasome pathway with proteasome inhibitors can cause apoptosis independently of p53. Therefore, this finding helps reconcile the p53 transcriptional independence of apoptosis caused by Delta12-prostaglandin J(2). This discovery represents a novel mechanism for proteasome pathway inhibition in intact cells. Furthermore, it identifies isopeptidases as novel targets for the development of antineoplastic agents.
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84108, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Mullally
authors.forename: P J
authors.initials: PJ
authors.lastname: Moos
authors.forename: K
authors.initials: K
authors.lastname: Edes
authors.forename: F A
authors.initials: FA
authors.lastname: Fitzpatrick
mesh_terms: D000447:Aldehydes / Q000494:pharmacology; D017209:Apoptosis; D001704:Biopolymers / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D003517:Cyclopentanes / Q000737:chemistry*; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D010450:Endopeptidases / Q000378:metabolism*; D000939:Epitopes; D016158:Genes, p53 / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D007659:Ketones / Q000737:chemistry; D008954:Models, Biological; D008956:Models, Chemical; D009097:Multienzyme Complexes / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D025821:Polyubiquitin; D011453:Prostaglandins / Q000737:chemistry*; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding; D011487:Protein Conformation; D013997:Time Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014452:Ubiquitins / Q000378:metabolism
chemical_list: D000447:Aldehydes; D001704:Biopolymers; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D003517:Cyclopentanes; D015853:Cysteine Proteinase Inhibitors; D000939:Epitopes; D007659:Ketones; D009097:Multienzyme Complexes; D011453:Prostaglandins; D016159:Tumor Suppressor Protein p53; D014452:Ubiquitins; D025821:Polyubiquitin; D010450:Endopeptidases; D010447:Peptide Hydrolases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; C091939:ubiquitin isopeptidase; C027576:4-hydroxy-2-nonenal; C013905:cyclopentenone