title: Image-based screening for the identification of novel proteasome inhibitors.
abstract: The proteasome is a new, interesting target in cancer drug therapy, and the proteasome inhibitor bortezomib has shown an effect in myeloma patients. It is of interest to efficiently discover and evaluate new proteasome inhibitors. The authors describe the development of an image-based screening assay for the identification of compounds with proteasome-inhibiting activity. The stably transfected human embryo kidney cell line HEK 293 ZsGreen Proteasome Sensor Cell Line expressing the ZsProSensor-1 fusion protein was used for screening and evaluation of proteasome inhibitors. Inhibition of the proteasome leads to accumulation of the green fluorescent protein ZsGreen, which is measured in the ArrayScan High Content Screening system, in which cell morphology is studied simultaneously. When screening the LOPAC(1280) substance library, several compounds with effect on the proteasome were found; among the hits were disulfiram and ammonium pyrrolidinedithiocarbamate (PDTC). Cytotoxic analysis of disulfiram and PDTC showed that the compounds induced cytotoxicity in the myeloma cell line RPMI 8226. The average Z' value for the assay was 0.66. The results indicate that the assay rapidly identifies new proteasome-inhibiting substances, and it will be further used as a tool for image-based screening of other chemically diverse compound libraries.
authors.affiliation: Department of Medical Sciences, Division of Clinical Pharmacology, Uppsala University Hospital, 751 85 Uppsala, Sweden. linda.rickardson@medsci.uu.se
authors.forename: Linda
authors.initials: L
authors.lastname: Rickardson
authors.forename: Malin
authors.initials: M
authors.lastname: Wickström
authors.forename: Rolf
authors.initials: R
authors.lastname: Larsson
authors.forename: Henrik
authors.initials: H
authors.lastname: Lövborg
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000295:instrumentation* / Q000379:methods*; D002460:Cell Line; D045744:Cell Line, Tumor; D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D005240:Feasibility Studies; D005470:Fluorometry; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D020128:Inhibitory Concentration 50; D051379:Mice; D009101:Multiple Myeloma / Q000188:drug therapy; D009369:Neoplasms / Q000188:drug therapy; D009955:Ornithine Decarboxylase / Q000235:genetics / Q000378:metabolism; D061988:Proteasome Inhibitors; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012985:Software Design
chemical_list: D004791:Enzyme Inhibitors; D061988:Proteasome Inhibitors; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D009955:Ornithine Decarboxylase