MRT-92 inhibits Hedgehog signaling by blocking overlapping binding sites in the transmembrane domain of the Smoothened receptor. - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue FASEB Journal Année : 2015

MRT-92 inhibits Hedgehog signaling by blocking overlapping binding sites in the transmembrane domain of the Smoothened receptor.

Résumé

The Smoothened (Smo) receptor, a member of class F G protein-coupled receptors, is the main transducer of the Hedgehog (Hh) signaling pathway implicated in a wide range of developmental and adult processes. Smo is the target of anticancer drugs that bind to a long and narrow cavity in the 7-transmembrane (7TM) domain. X-ray structures of human Smo (hSmo) bound to several ligands have revealed 2 types of 7TM-directed antagonists: those binding mostly to extracellular loops (site 1, e.g., LY2940680) and those penetrating deeply in the 7TM cavity (site 2, e.g., SANT-1). Here we report the development of the acylguanidine MRT-92, which displays subnanomolar antagonist activity against Smo in various Hh cell-based assays. MRT-92 inhibits rodent cerebellar granule cell proliferation induced by Hh pathway activation through pharmacologic (half maximal inhibitory concentration [IC50] = 0.4 nM) or genetic manipulation. Using [3H]MRT-92 (Kd = 0.3 nM for hSmo), we created a comprehensive framework for the interaction of small molecule modulators with hSmo and for understanding chemoresistance linked to hSmo mutations. Guided by molecular docking and site-directed mutagenesis data, our work convincingly confirms that MRT-92 simultaneously recognized and occupied both sites 1 and 2. Our data demonstrate the existence of a third type of Smo antagonists, those entirely filling the Smo binding cavity from the upper extracellular part to the lower cytoplasmic-proximal subpocket. Our studies should help design novel potent Smo antagonists and more effective therapeutic strategies for treating Hh-linked cancers and associated chemoresistance.-Hoch, L., Faure, H., Roudaut, H., Schoenfelder, A., Mann, A., Girard, N., Bihannic, L., Ayrault, A. Petricci, E., Taddei, M., Rognan, D., Ruat, M. MRT-92 inhibits Hedgehog signaling by blocking overlapping binding sites in the transmembrane domain of the Smoothened receptor.

Dates et versions

hal-01142537 , version 1 (15-04-2015)

Identifiants

Citer

Lucile Hoch, Hélène Faure, Hermine Roudaut, Angele Schoenfelder, André Mann, et al.. MRT-92 inhibits Hedgehog signaling by blocking overlapping binding sites in the transmembrane domain of the Smoothened receptor.. FASEB Journal, 2015, 29 (5), pp.1817-1829 ⟨10.1096/fj.14-267849⟩. ⟨hal-01142537⟩
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