title: Synthesis, in silico, in vitro, and in vivo investigation of 5-[¹¹C]methoxy-substituted sunitinib, a tyrosine kinase inhibitor of VEGFR-2.
abstract: Sunitinib (SU11248) is a highly potent tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor (VEGFR). Radiolabeled inhibitors of receptor tyrosine kinases (RTKs) might be useful tools for monitoring RTKs levels in tumor tissue giving valuable information for anti-angiogenic therapy. Herein we report the synthesis of 5-methoxy-sunitinib 5 and its (11)C-radiolabeled analog [(11)C]-5. The non-radioactive reference compound 5 was prepared by Knoevenagel condensation of 5-methoxy-2-oxindole with the corresponding substituted 5-formyl-1H-pyrrole. A binding constant (K(d)) of 20 nM for 5 was determined by competition binding assay against VEGFR-2. In addition, the binding mode of sunitinib and its 5-methoxy substituted derivative was studied by flexible docking simulations. These studies revealed that the substitution of the fluorine at position 5 of the oxindole scaffold by a methoxy group did not affect the inhibitor orientation, but affected the electrostatic and van der Waals interactions of the ligand with residues near the DFG motif of VEGFR-2. 5-[(11)C]methoxy-sunitinib ([(11)C]-5) was synthesized by reaction of the desmethyl precursor with [(11)C]CH(3)I in the presence of DMF and NaOH in 17 ± 3% decay-corrected radiochemical yield at a specific activity of 162-205 GBq/μmol (EOS). In vivo stability studies of [(11)C]-5 in rat blood showed that more than 70% of the injected compound was in blood stream, 60 min after administration.
authors.affiliation: Centro de Bioinformática y Simulación Molecular, Universidad de Talca, 2 Norte 685, Casilla 721, Talca, Chile.
authors.forename: Julio
authors.initials: J
authors.lastname: Caballero
authors.forename: Camila
authors.initials: C
authors.lastname: Muñoz
authors.forename: Jans H
authors.initials: JH
authors.lastname: Alzate-Morales
authors.forename: Susana
authors.initials: S
authors.lastname: Cunha
authors.forename: Lurdes
authors.initials: L
authors.lastname: Gano
authors.forename: Ralf
authors.initials: R
authors.lastname: Bergmann
authors.forename: Joerg
authors.initials: J
authors.lastname: Steinbach
authors.forename: Torsten
authors.initials: T
authors.lastname: Kniess
mesh_terms: D002247:Carbon Isotopes; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007211:Indoles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D015394:Molecular Structure; D047428:Protein Kinase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011758:Pyrroles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D000077210:Sunitinib; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D007211:Indoles; D047428:Protein Kinase Inhibitors; D011758:Pyrroles; D040301:Vascular Endothelial Growth Factor Receptor-2; D000077210:Sunitinib