title: Synthesis of cetuximab-immunoliposomes via a cholesterol-based membrane anchor for targeting of EGFR.
abstract: The objective of the present study was to construct epidermal growth factor receptor (EGFR) targeting cetuximab-immunoliposomes (ILs) for targeted delivery of boron compounds to EGFR(+) glioma cells for neutron capture therapy. The ILs were synthesized by using a novel cholesterol-based membrane anchor, maleimido-PEG-cholesterol (Mal-PEG-Chol), to incorporate cetuximab into liposomes by either surface conjugation or a post-insertion method. For post-insertion, the transfer efficiency of MAb conjugates from micelles to liposome was examined at varying temperatures, mPEG2000-DSPE ratios, and micelle-to-liposome lipid ratios. Following this, the cetuximab-ILs were evaluated for targeted delivery of the encapsulated boron anion, dodecahydro-closo-dodecaborate (2-) (B12H122-), to human EGFR gene transfected F98EGFR glioma cells as potential delivery agents for boron neutron capture therapy (BNCT). In addition, cellular uptake of cetuximab-ILs, encapsulating a fluorescence dye, was analyzed by confocal fluorescence microscopy and flow cytometry, and boron content was quantified by ICP-MS. Much greater ( approximately 8-fold) cellular uptake of boron was obtained using cetuximab-ILs in EGFR(+) F98EGFR compared with nontargeted human IgG-ILs. On the basis of these observations, we have concluded that cholesterol can serve as an effective anchor for MAb in liposomes, and cetuximab-ILs are potentially useful delivery vehicles for BNCT of gliomas.
authors.affiliation: Division of Pharmaceutics, College of Pharmacy, NSF Nanoscale Science and Engineering Center (NSEC), Center for Affordable Nanoengineering of Polymeric Biomedical Devices (CANPBD), The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Pan
authors.forename: Gong
authors.initials: G
authors.lastname: Wu
authors.forename: Weiliang
authors.initials: W
authors.lastname: Yang
authors.forename: Rolf F
authors.initials: RF
authors.lastname: Barth
authors.forename: Werner
authors.initials: W
authors.lastname: Tjarks
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Lee
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D061067:Antibodies, Monoclonal, Humanized; D045744:Cell Line, Tumor; D000068818:Cetuximab; D002784:Cholesterol / Q000737:chemistry*; D066246:ErbB Receptors / Q000276:immunology*; D006801:Humans; D007700:Kinetics; D008081:Liposomes; D008823:Micelles; D015394:Molecular Structure
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D008081:Liposomes; D008823:Micelles; D002784:Cholesterol; D066246:ErbB Receptors; D000068818:Cetuximab