title: Activity probe for in vivo profiling of the specificity of proteasome inhibitor bortezomib.
abstract: Proteasome inhibitors, such as the dipeptide boronic acid bortezomib, are emerging as important tools in the treatment of the fatal hematologic malignancy multiple myeloma. Despite the recent US Food and Drug Administration approval of bortezomib (PS341, Velcade) for the treatment of refractory multiple myeloma, many of the basic pharmacologic parameters of bortezomib and its mode of action on myeloma cells remain to be determined. We describe the synthesis and use of a cell-permeant active site-directed probe, which allows profiling of proteasomal activities in living cells. When we compared proteasome activity patterns in cultured cells and crude cell extracts with this probe, we observed substantial differences, stressing the importance for bioassays compatible with live cells to ensure accuracy of such measurements. Using this probe, we investigated the in vivo subunit specificities of bortezomib and another inhibitor, MG132.
authors.affiliation: Department of Pathology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA.
authors.forename: Celia R
authors.initials: CR
authors.lastname: Berkers
authors.forename: Martijn
authors.initials: M
authors.lastname: Verdoes
authors.forename: Eben
authors.initials: E
authors.lastname: Lichtman
authors.forename: Edda
authors.initials: E
authors.lastname: Fiebiger
authors.forename: Benedikt M
authors.initials: BM
authors.lastname: Kessler
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Anderson
authors.forename: Hidde L
authors.initials: HL
authors.lastname: Ploegh
authors.forename: Huib
authors.initials: H
authors.lastname: Ovaa
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Galardy
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001897:Boronic Acids / Q000494:pharmacology*; D000069286:Bortezomib; D045744:Cell Line, Tumor / Q000187:drug effects; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D051379:Mice; D009101:Multiple Myeloma / Q000188:drug therapy; D011480:Protease Inhibitors / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex / Q000494:pharmacology; D011719:Pyrazines / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D001897:Boronic Acids; D007976:Leupeptins; D011480:Protease Inhibitors; D011719:Pyrazines; D000069286:Bortezomib; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde