title: Growth inhibition of breast cancer cell lines overexpressing Her2/neu by a novel internalized fully human Fab antibody fragment.
abstract: The Her2/neu oncogene is overexpressed in various human cancers of epithelial origin and is associated with increased metastatic potential and poor prognosis. Blocking the Her2/neu signalling has been the focus of most therapeutic approaches. In this paper, the Her2/neu extracellular domain expressed in soluble form in yeast Pichia pastoris was used in order to isolate a fully human Fab fragment from a combinatorial Fab phage display library, derived from invaded lymph nodes of a breast cancer patient. The isolated fully human Fab63 binds specifically the native Her2/neu receptor and competes with Herceptin for binding to soluble Her2/neu receptor. In Her2/neu overexpressing cancer cells, Fab63 is rapidly internalized and has significant antiproliferative effects, where ligand-independent mechanisms dominate signal induction. Moreover, in the presence of the ligand heregulin, growth inhibition was also detected by Fab63. The human Fab63 is a non-immunogenic agent with unique properties that can be applied in diagnosis and cancer therapy, with great potential for further manipulation towards the generation of an effective anticancer molecule.
authors.affiliation: Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, 127 Vas. Sofias Ave., 11521 Athens, Greece.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Belimezi
authors.forename: Danai
authors.initials: D
authors.lastname: Papanastassiou
authors.forename: Efrossini
authors.initials: E
authors.lastname: Merkouri
authors.forename: Constantin N
authors.initials: CN
authors.lastname: Baxevanis
authors.forename: Avgi
authors.initials: A
authors.lastname: Mamalaki
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D000918:Antibody Specificity; D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology; D018613:Microscopy, Confocal; D019151:Peptide Library; D010843:Pichia / Q000737:chemistry / Q000235:genetics; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000068878:Trastuzumab; D015854:Up-Regulation
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D007140:Immunoglobulin Fab Fragments; D019151:Peptide Library; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab