title: DFG-out mode of inhibition by an irreversible type-1 inhibitor capable of overcoming gate-keeper mutations in FGF receptors.
abstract: Drug-resistance acquisition through kinase gate-keeper mutations is a major hurdle in the clinic. Here, we determined the first crystal structures of the human FGFR4 kinase domain (FGFR4K) alone and complexed with ponatinib, a promiscuous type-2 (DFG-out) kinase inhibitor, and an oncogenic FGFR4K harboring the V550L gate-keeper mutation bound to FIIN-2, a new type-1 irreversible inhibitor. Remarkably, like ponatinib, FIIN-2 also binds in the DFG-out mode despite lacking a functional group necessary to occupy the pocket vacated upon the DFG-out flip. Structural analysis reveals that the covalent bond between FIIN-2 and a cysteine, uniquely present in the glycine-rich loop of FGFR kinases, facilitates the DFG-out conformation, which together with the internal flexibility of FIIN-2 enables FIIN-2 to avoid the steric clash with the gate-keeper mutation that causes the ponatinib resistance. The structural data provide a blueprint for the development of next generation anticancer inhibitors through combining the salient inhibitory mechanisms of ponatinib and FIIN-2.
authors.affiliation: School of Pharmacy, Wenzhou Medical University , Wenzhou, Zhejiang 325035, China.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Huang
authors.forename: Li
authors.initials: L
authors.lastname: Tan
authors.forename: Huiyan
authors.initials: H
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Steven
authors.initials: S
authors.lastname: Blais
authors.forename: Jingjing
authors.initials: J
authors.lastname: Deng
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Neubert
authors.forename: Nathanael S
authors.initials: NS
authors.lastname: Gray
authors.forename: Xiaokun
authors.initials: X
authors.lastname: Li
authors.forename: Moosa
authors.initials: M
authors.lastname: Mohammadi
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D018360:Crystallography, X-Ray; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D009154:Mutation; D009842:Oligopeptides / Q000737:chemistry; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D051499:Receptor, Fibroblast Growth Factor, Type 4 / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry
chemical_list: C553185:DFG peptide; D009842:Oligopeptides; D047428:Protein Kinase Inhibitors; C496371:FGFR4 protein, human; D051499:Receptor, Fibroblast Growth Factor, Type 4