title: First identification of small-molecule inhibitors of Pontin by combining virtual screening and enzymatic assay.
abstract: The human protein Pontin, which belongs to the AAA+ (ATPases associated with various cellular activities) family, is overexpressed in several cancers and its silencing in vitro leads to tumour cell growth arrest and apoptosis, making it a good target for cancer therapy. In particular, high levels of expression were found in hepatic tumours for which the therapeutic arsenal is rather limited. The three-dimensional structure of Pontin has been resolved previously, revealing a hexameric assembly with one ADP molecule co-crystallized in each subunit. Using Vina, DrugScore and Xscore, structure-based virtual screening of 2200 commercial molecules was conducted into the ATP-binding site formed by a dimer of Pontin in order to prioritize the best candidates. Complementary to the in silico screening, a versatile and sensitive colorimetric assay was set up to measure the disruption of the ATPase activity of Pontin. This assay allowed the determination of inhibition curves for more than 20 top-scoring compounds, resulting in the identification of four ligands presenting an inhibition constant in the micromolar concentration range. Three of them inhibited tumour cell proliferation. The association of virtual screening and experimental assay thus proved successful for the discovery of the first small-molecule inhibitors of Pontin.
authors.affiliation: Molecular Modeling Group, IECB-CNRS-Université de Bordeaux, UMR 5248, Pessac, France.
authors.forename: Judith
authors.initials: J
authors.lastname: Elkaim
authors.forename: Michel
authors.initials: M
authors.lastname: Castroviejo
authors.forename: Driss
authors.initials: D
authors.lastname: Bennani
authors.forename: Said
authors.initials: S
authors.lastname: Taouji
authors.forename: Nathalie
authors.initials: N
authors.lastname: Allain
authors.forename: Michel
authors.initials: M
authors.lastname: Laguerre
authors.forename: Jean
authors.initials: J
authors.lastname: Rosenbaum
authors.forename: Jean
authors.initials: J
authors.lastname: Dessolin
authors.forename: Patrick
authors.initials: P
authors.lastname: Lestienne
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D002352:Carrier Proteins / Q000037:antagonists & inhibitors*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004265:DNA Helicases / Q000037:antagonists & inhibitors*; D057075:Enzyme Assays; D006801:Humans; D008958:Models, Molecular; D054730:Protein Interaction Domains and Motifs; D054852:Small Molecule Libraries / Q000494:pharmacology*
chemical_list: D002352:Carrier Proteins; D054852:Small Molecule Libraries; D000074183:ATPases Associated with Diverse Cellular Activities; D004265:DNA Helicases; C486549:RUVBL1 protein, human