title: A novel small-molecule screening strategy identifies mitoxantrone as a RhoGTPase inhibitor.
abstract: RhoGTPases are GDP/GTP molecular switches that control a wide variety of cellular processes, thereby contributing to many diseases, including cancer. As a consequence, there is great interest in the identification of small-molecule inhibitors of RhoGTPases. In the present paper, using the property of GTP-loaded RhoGTPases to bind to their effectors, we describe a miniaturized and robust assay to monitor Rac1 GTPase activation that is suitable for large-scale high-throughput screening. A pilot compound library screen revealed that the topoisomerase II poison MTX (mitoxantrone) is an inhibitor of Rac1, and also inhibits RhoA and Cdc42 in vitro. We show that MTX prevents GTP binding to RhoA/Rac1/Cdc42 in vitro. Furthermore, MTX strongly inhibits RhoGTPase-mediated F-actin (filamentous actin) reorganization and cell migration. Hence, we report a novel biochemical assay yielding the identification of RhoGTPase inhibitors and we present a proof-of-concept validation with the identification of MTX as a novel pan-RhoGTPase inhibitor.
authors.affiliation: Université de Bordeaux, CNRS UMR 5248, CBMN, IECB, F-33607 Pessac Cedex, France.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Bidaud-Meynard
authors.forename: Daniela
authors.initials: D
authors.lastname: Arma
authors.forename: Said
authors.initials: S
authors.lastname: Taouji
authors.forename: Michel
authors.initials: M
authors.lastname: Laguerre
authors.forename: Jean
authors.initials: J
authors.lastname: Dessolin
authors.forename: Jean
authors.initials: J
authors.lastname: Rosenbaum
authors.forename: Eric
authors.initials: E
authors.lastname: Chevet
authors.forename: Violaine
authors.initials: V
authors.lastname: Moreau
mesh_terms: D000818:Animals; D002465:Cell Movement; D042783:Endothelial Cells / Q000502:physiology; D057166:High-Throughput Screening Assays; D006801:Humans; D008942:Mitoxantrone / Q000494:pharmacology*; D015398:Signal Transduction; D013552:Swine; D020764:cdc42 GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C107953:RAC1 protein, human; D008942:Mitoxantrone; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein