PT  - JOURNAL ARTICLE
AU  - Gorojankina, Tatiana
AU  - Hoch, Lucile
AU  - Faure, Hélène
AU  - Roudaut, Hermine
AU  - Traiffort, Elisabeth
AU  - Schoenfelder, Angèle
AU  - Girard, Nicolas
AU  - Mann, André
AU  - Manetti, Fabrizio
AU  - Solinas, Antonio
AU  - Petricci, Elena
AU  - Taddei, Maurizio
AU  - Ruat, Martial
TI  - Discovery, Molecular and Pharmacological Characterization of GSA-10, a Novel Small-Molecule Positive Modulator of Smoothened
AID  - 10.1124/mol.112.084590
DP  - 2013 May 01
TA  - Molecular Pharmacology
PG  - 1020--1029
VI  - 83
IP  - 5
4099  - http://molpharm.aspetjournals.org/content/83/5/1020.short
4100  - http://molpharm.aspetjournals.org/content/83/5/1020.full
SO  - Mol Pharmacol2013 May 01; 83
AB  - 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.