title: A combination of two antibodies recognizing non-overlapping epitopes of HER2 induces kinase activity-dependent internalization of HER2.
abstract: The human epidermal growth factor receptor 2 (HER2/ErbB2) is overexpressed in a number of human cancers. HER2 is the preferred heterodimerization partner for other epidermal growth factor receptor (EGFR) family members and is considered to be resistant to endocytic down-regulation, properties which both contribute to the high oncogenic potential of HER2. Antibodies targeting members of the EGFR family are powerful tools in cancer treatment and can function by blocking ligand binding, preventing receptor dimerization, inhibiting receptor activation and/or inducing receptor internalization and degradation. With respect to antibody-induced endocytosis of HER2, various results are reported, and the effect seems to depend on the HER2 expression level and whether antibodies are given as individual antibodies or as mixtures of two or more. In this study, the effect of a mixture of two monoclonal antibodies against non-overlapping epitopes of HER2 was investigated with respect to localization and stability of HER2. Individual antibodies had limited effect, but the combination of antibodies induced internalization and degradation of HER2 by multiple endocytic pathways. In addition, HER2 was phosphorylated and ubiquitinated upon incubation with the antibody combination, and the HER2 kinase activity was found to be instrumental in antibody-induced HER2 down-regulation.
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Monika
authors.initials: M
authors.lastname: Szymanska
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Fosdahl
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Filip
authors.initials: F
authors.lastname: Nikolaysen
authors.affiliation: Symphogen A/S, Ballerup, Denmark.
authors.forename: Mikkel W
authors.initials: MW
authors.lastname: Pedersen
authors.affiliation: Symphogen A/S, Ballerup, Denmark.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Grandal
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.
authors.forename: Espen
authors.initials: E
authors.lastname: Stang
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway. vibeke.bertelsen@rr-research.no.
authors.forename: Vibeke
authors.identifier: 0000-0002-8654-4978
authors.initials: V
authors.lastname: Bertelsen
mesh_terms: D000199:Actins / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000494:pharmacology; D002460:Cell Line; D002966:Clathrin / Q000378:metabolism; D034281:Dynamins / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D010766:Phosphorylation / Q000187:drug effects; D010873:Pinocytosis / Q000187:drug effects; D058105:Polymerization / Q000187:drug effects; D059748:Proteolysis / Q000187:drug effects; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology*; D054875:Ubiquitination / Q000187:drug effects
chemical_list: D000199:Actins; D000911:Antibodies, Monoclonal; D002966:Clathrin; D034281:Dynamins; D000939:Epitopes; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: HER2/ErbB2; antibody combinations; degradation; endocytosis; kinase activity; monoclonal antibodies