title: Denosumab mimics the natural decoy receptor osteoprotegerin by interacting with its major binding site on RANKL.
abstract: Bone homeostasis critically relies on the RANKL-RANK-OPG axis which can be targeted by the fully human monoclonal antibody denosumab in conditions with increased bone resporption such as bone metastases. The binding site and therefore the molecular mechanism by which this antibody inhibits RANKL has not been characterized so far. Here, we used random peptide phage display library screenings to identify the denosumab epitope on RANKL. Alignments of phage derived peptide sequences with RANKL suggested that this antibody recognized a linear epitope between position T233 and Y241. Mutational analysis confirmed the core residues as critical for this interaction. The spatial localization of this epitope on a 3-dimensional model of RANKL showed that it overlapped with the major binding sites of OPG and RANK on RANKL. We conclude that denosumab inhibits RANKL by both functional and molecular mimicry of the natural decoy receptor OPG.
authors.affiliation: Department of Oncology and Hematology, BMT with section Pneumology, Hubertus Wald Tumorzentrum / UCCH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Aneta
authors.initials: A
authors.lastname: Schieferdecker
authors.affiliation: Department of Oncology and Hematology, BMT with section Pneumology, Hubertus Wald Tumorzentrum / UCCH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Mareike
authors.initials: M
authors.lastname: Voigt
authors.affiliation: Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Riecken
authors.affiliation: Department of Oncology and Hematology, BMT with section Pneumology, Hubertus Wald Tumorzentrum / UCCH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Friederike
authors.initials: F
authors.lastname: Braig
authors.affiliation: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Schinke
authors.affiliation: Department of Oncology and Hematology, BMT with section Pneumology, Hubertus Wald Tumorzentrum / UCCH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Institute for Tumor Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Loges
authors.affiliation: Department of Oncology and Hematology, BMT with section Pneumology, Hubertus Wald Tumorzentrum / UCCH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Bokemeyer
authors.affiliation: Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Fehse
authors.affiliation: Department of Oncology and Hematology, BMT with section Pneumology, Hubertus Wald Tumorzentrum / UCCH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Mascha
authors.initials: M
authors.lastname: Binder
mesh_terms: D000595:Amino Acid Sequence; D061067:Antibodies, Monoclonal, Humanized / Q000276:immunology / Q000494:pharmacology*; D001665:Binding Sites; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000069448:Denosumab; D018604:Epitope Mapping; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D057809:HEK293 Cells; D006801:Humans; D008958:Models, Molecular; D053244:Osteoprotegerin / Q000378:metabolism*; D019151:Peptide Library; D010455:Peptides / Q000276:immunology; D053245:RANK Ligand / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000378:metabolism; D020539:Sequence Analysis, Protein
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000939:Epitopes; D053244:Osteoprotegerin; D019151:Peptide Library; D010455:Peptides; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505686:TNFRSF11A protein, human; C505688:TNFSF11 protein, human; D000069448:Denosumab