title: Characterization and cancer cell specific binding properties of anti-EGFR antibody conjugated quantum dots.
abstract: Synthesis of biologically active antibody conjugated quantum dots (QDs) has been of great importance in cellular imaging and diagnostics. Cetuximab (or Erbitux) is the first monoclonal antibody drug which targets the epidermal growth factor receptor (EGFR) overexpressed in most cancer cells. In the present work, we investigated three different conjugation strategies to obtain the biologically functional QD-cetuximab conjugates for the tumor-specific imaging. Successful conjugation of cetuximab to QDs was achieved using PEG conjugated polymer-coated QDs and two long-chain heterobifunctional linkers, sulfo-LC-SPDP and sulfo-SMCC. The dissociation constant of the QD-cetuximab conjugates to EGFR was determined to be 0.61 +/- 0.28 nM. The cancer cell-specific binding ability of the QD-cetuximab conjugates was evaluated in vitro, and the cellular internalization of the QD-cetuximab conjugates was clearly demonstrated in live cells by confocal microscopy. The cellular imaging experiments using the QD-cetuximab conjugates showed a clear endocytosis pathway, which was evidenced by the colocalization of the QD-cetuximab conjugates with dye-labeled transferrin. These results suggest that the QD-cetuximab conjugates as an imaging modality for tumor EGFR overexpression can be expected to provide important information on the expression levels of EGFR on the cancer cells.
authors.affiliation: Nano/Bio Chemistry Laboratory, Institut Pasteur Korea, 696 Sampyeong-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-400, South Korea.
authors.forename: Junghan
authors.initials: J
authors.lastname: Lee
authors.forename: Youngseon
authors.initials: Y
authors.lastname: Choi
authors.forename: Keumhyun
authors.initials: K
authors.lastname: Kim
authors.forename: Sukmin
authors.initials: S
authors.lastname: Hong
authors.forename: Hye-Young
authors.initials: HY
authors.lastname: Park
authors.forename: Taesup
authors.initials: T
authors.lastname: Lee
authors.forename: Gi Jeong
authors.initials: GJ
authors.lastname: Cheon
authors.forename: Rita
authors.initials: R
authors.lastname: Song
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology*; D061067:Antibodies, Monoclonal, Humanized; D002277:Carcinoma / Q000175:diagnosis; D045744:Cell Line, Tumor; D000068818:Cetuximab; D066246:ErbB Receptors / Q000276:immunology*; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis; D009369:Neoplasms / Q000175:diagnosis*; D011092:Polyethylene Glycols / Q000737:chemistry; D045663:Quantum Dots
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D011092:Polyethylene Glycols; D066246:ErbB Receptors; D000068818:Cetuximab