title: Discovery, molecular and pharmacological characterization of GSA-10, a novel small-molecule positive modulator of Smoothened.
abstract: Activation of the Smoothened (Smo) receptor mediates Hedgehog (Hh) signaling. Hh inhibitors are in clinical trials for cancer, and small-molecule Smo agonists may have therapeutic interests in regenerative medicine. Here, we have generated and validated a pharmacophoric model for Smo agonists and used this model for the virtual screening of a library of commercially available compounds. Among the 20 top-scoring ligands, we have identified and characterized a novel quinolinecarboxamide derivative, propyl 4-(1-hexyl-4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxamido) benzoate, (GSA-10), as a Smo agonist. GSA-10 fits to the agonist pharmacophoric model with two hydrogen bond acceptor groups and four hydrophobic regions. Using pharmacological, biochemical, and molecular approaches, we provide compelling evidence that GSA-10 acts at Smo to promote the differentiation of multipotent mesenchymal progenitor cells into osteoblasts. However, this molecule does not display the hallmarks of reference Smo agonists. Remarkably, GSA-10 does not recognize the classic bodipy-cyclopamine binding site. Its effect on cell differentiation is inhibited by Smo antagonists, such as MRT-83, SANT-1, LDE225, and M25 in the nanomolar range, by GDC-0449 in the micromolar range, but not by cyclopamine and CUR61414. Thus, GSA-10 allows the pharmacological characterization of a novel Smo active site, which is notably not targeted to the primary cilium and strongly potentiated by forskolin and cholera toxin. GSA-10 belongs to a new class of Smo agonists and will be helpful for dissecting Hh mechanism of action, with important implications in physiology and in therapy.
authors: CNRS, UPR-3294, Laboratoire de Neurobiologie et Développement, Institut de Neurobiologie Alfred Fessard IFR2118, Gif-sur-Yvette, France.
authors: Tatiana
authors: T
authors: Gorojankina
authors: Lucile
authors: L
authors: Hoch
authors: Hélène
authors: H
authors: Faure
authors: Hermine
authors: H
authors: Roudaut
authors: Elisabeth
authors: E
authors: Traiffort
authors: Angèle
authors: A
authors: Schoenfelder
authors: Nicolas
authors: N
authors: Girard
authors: André
authors: A
authors: Mann
authors: Fabrizio
authors: F
authors: Manetti
authors: Antonio
authors: A
authors: Solinas
authors: Elena
authors: E
authors: Petricci
authors: Maurizio
authors: M
authors: Taddei
authors: Martial
authors: M
authors: Ruat
mesh_terms: D001565:Benzoates / Q000494:pharmacology; D001665:Binding Sites / Q000187:drug effects; D052004:Bone Morphogenetic Protein Receptors / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D003514:Cyclohexylamines / Q000494:pharmacology; D057809:HEK293 Cells; D053823:Hedgehog Proteins / Q000378:metabolism; D006801:Humans; D008024:Ligands; D011804:Quinolines / Q000494:pharmacology*; D043562:Receptors, G-Protein-Coupled / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000378:metabolism*; D054852:Small Molecule Libraries; D000072086:Smoothened Receptor; D013876:Thiophenes / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism; D000071676:Zinc Finger Protein GLI1
chemical_list: C530252:2-quinolinecarboxamide; D001565:Benzoates; D003514:Cyclohexylamines; C400551:GLI1 protein, human; D053823:Hedgehog Proteins; D008024:Ligands; D011804:Quinolines; D043562:Receptors, G-Protein-Coupled; C468918:SAG compound; C491023:SMO protein, human; D054852:Small Molecule Libraries; D000072086:Smoothened Receptor; D013876:Thiophenes; D014157:Transcription Factors; D051153:Wnt Proteins; D000071676:Zinc Finger Protein GLI1; D000242:Cyclic AMP; D052004:Bone Morphogenetic Protein Receptors