title: [(64) Cu]-labelled trastuzumab: optimisation of labelling by DOTA and NODAGA conjugation and initial evaluation in mice.
abstract: The human epidermal growth factor receptor-2 (HER2) is overexpressed in 20-30% of all breast cancer cases, leading to increased cell proliferation, growth and migration. The monoclonal antibody, trastuzumab, binds to HER2 and is used for treatment of HER2-positive breast cancer. Trastuzumab has previously been labelled with copper-64 by conjugation of a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator. The aim of this study was to optimise the (64) Cu-labelling of DOTA-trastuzumab and as the first to produce and compare with its 1,4,7-triazacyclononane, 1-glutaric acid-5,7 acetic acid (NODAGA) analogue in a preliminary HER2 tumour mouse model. The chelators were conjugated to trastuzumab using the activated esters DOTA mono-N-hydroxysuccinimide (NHS) and NODAGA-NHS. (64) Cu-labelling of DOTA-trastuzumab was studied by varying the amount of DOTA-trastuzumab used, reaction temperature and time. Full (64) Cu incorporation could be achieved using a minimum of 10-µg DOTA-trastuzumab, but the fastest labelling was obtained after 15 min at room temperature using 25 µg of DOTA-trastuzumab. In comparison, 80% incorporation was achieved for (64) Cu-labelling of NODAGA-trastuzumab. Both [(64) Cu]DOTA-trastuzumab and [(64) Cu]NODAGA-trastuzumab were produced after purification with radiochemical purities of >97%. The tracers were injected into mice with HER2 expressing tumours. The mice were imaged by positron emission tomography and showed high tumour uptake of 3-9% ID/g for both tracers.
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark.|Cluster for Molecular Imaging, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Christina
authors.initials: C
authors.lastname: Schjoeth-Eskesen
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark.|Cluster for Molecular Imaging, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Carsten Haagen
authors.initials: CH
authors.lastname: Nielsen
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
authors.forename: Søren
authors.initials: S
authors.lastname: Heissel
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Højrup
authors.affiliation: Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Paul Robert
authors.initials: PR
authors.lastname: Hansen
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Nic
authors.initials: N
authors.lastname: Gillings
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen, Denmark.|Cluster for Molecular Imaging, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kjaer
mesh_terms: D000085:Acetates / Q000737:chemistry; D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000493:pharmacokinetics; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry; D051379:Mice; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D011485:Protein Binding; D019275:Radiopharmaceuticals / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D014018:Tissue Distribution; D000068878:Trastuzumab
chemical_list: D000085:Acetates; D061067:Antibodies, Monoclonal, Humanized; D006573:Heterocyclic Compounds, 1-Ring; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C572723:1-(1,3-carboxypropyl)-4,7-carboxymethyl-1,4,7-triazacyclononane; C546788:64Cu-DOTA-trastuzumab; C524056:Erbb2 protein, mouse
keywords: DOTA; NODAGA; PET; trastuzumab