title: Virtual screening-based discovery and mechanistic characterization of the acylthiourea MRT-10 family as smoothened antagonists.
abstract: The seven-transmembrane receptor Smoothened (Smo) is the major component involved in signal transduction of the Hedgehog (Hh) morphogens. Smo inhibitors represent a promising alternative for the treatment of several types of cancers linked to abnormal Hh signaling. Here, on the basis of experimental data, we generated and validated a pharmacophoric model for Smo inhibitors constituted by three hydrogen bond acceptor groups and three hydrophobic regions. We used this model for the virtual screening of a library of commercially available compounds. Visual and structural criteria allowed the selection of 20 top scoring ligands, and an acylthiourea, N-(3-benzamidophenylcarbamothioyl)-3,4,5-trimethoxybenzamide (MRT-10), was identified and characterized as a Smo antagonist. The corresponding acylurea, N-(3-benzamidophenylcarbamoyl)-3,4,5-trimethoxybenzamide (MRT-14), was synthesized and shown to display, in various Hh assays, an inhibitory potency comparable to or greater than that of reference Smo antagonists cyclopamine and N-((3S,5S)-1-(benzo[d][1,3]dioxol-5-ylmethyl)-5-(piperazine-1-carbonyl)pyrrolidin-3-yl)-N-(3-methoxybenzyl)-3,3-dimethylbutanamide (Cur61414). Focused virtual screening of the same library further identified five additional related antagonists. MRT-10 and MRT-14 constitute the first members of novel families of Smo antagonists. The described virtual screening approach is aimed at identifying novel modulators of Smo and of other G-protein coupled receptors.
authors.affiliation: Dipartimento Farmaco Chimico Tecnologico, Università degli Studi di Siena, Siena, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Manetti
authors.forename: Helene
authors.initials: H
authors.lastname: Faure
authors.forename: Hermine
authors.initials: H
authors.lastname: Roudaut
authors.forename: Tatiana
authors.initials: T
authors.lastname: Gorojankina
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Traiffort
authors.forename: Angele
authors.initials: A
authors.lastname: Schoenfelder
authors.forename: Andre
authors.initials: A
authors.lastname: Mann
authors.forename: Antonio
authors.initials: A
authors.lastname: Solinas
authors.forename: Maurizio
authors.initials: M
authors.lastname: Taddei
authors.forename: Martial
authors.initials: M
authors.lastname: Ruat
mesh_terms: D000818:Animals; D002460:Cell Line; D055808:Drug Discovery / Q000379:methods*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006801:Humans; D046609:Libraries, Digital; D051379:Mice; D008809:Mice, Inbred C3H; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors* / Q000502:physiology; D000072086:Smoothened Receptor; D013890:Thiourea / Q000737:chemistry* / Q000378:metabolism
chemical_list: D043562:Receptors, G-Protein-Coupled; C491022:Smo protein, mouse; D000072086:Smoothened Receptor; D013890:Thiourea