title: p53-dependent induction of apoptosis by proteasome inhibitors.
abstract: Proteolysis by the ubiquitin/proteasome pathway controls the intracellular levels of a number of proteins that regulate cell proliferation and cell cycle progression. To determine whether this pathway of protein turnover was also linked to apoptosis, we treated Rat-1 and PC12 cells with specific proteasome inhibitors. The peptide aldehydes PSI and MG115, which specifically inhibit the chymotrypsin-like activity of the proteasome, induced apoptosis of both cell types. In contrast, apoptosis was not induced by inhibitors of lysosomal proteases or by an alcohol analog of PSI. The tumor suppressor p53 rapidly accumulated in cells treated with proteasome inhibitors, as did the p53-inducible gene products p21 and Mdm-2. In addition, apoptosis induced by proteasome inhibitors was inhibited by expression of dominant-negative p53, whereas overexpression of wild-type p53 was sufficient to induce apoptosis of Rat-1 cells in transient transfection assays. Although other molecules may also be involved, these results suggest that stabilization and accumulation of p53 plays a key role in apoptosis induced by proteasome inhibitors.
authors.affiliation: Dana-Farber Cancer Institute and the Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: U G
authors.initials: UG
authors.lastname: Lopes
authors.forename: P
authors.initials: P
authors.lastname: Erhardt
authors.forename: R
authors.initials: R
authors.lastname: Yao
authors.forename: G M
authors.initials: GM
authors.lastname: Cooper
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D003546:Cysteine Endopeptidases / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects; D007976:Leupeptins / Q000494:pharmacology*; D009097:Multienzyme Complexes / Q000502:physiology*; D016716:PC12 Cells; D011480:Protease Inhibitors / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex; D051381:Rats; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
chemical_list: D007976:Leupeptins; D009097:Multienzyme Complexes; D011480:Protease Inhibitors; D016159:Tumor Suppressor Protein p53; C089486:carbobenzoxy-leucyl-leucyl-norvalinal; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex