Browsing by Author "Dearling, JLJ"

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    Imaging cancer using PET - the effect of the bifunctional chelator on the biodistribution of a 64Cu-labeled antibody.
    (Elsevier, 2011-01-01) Dearling, JLJ; Voss, SD; Dunning, P; Snay, E; Fahey, F; Smith, SV; Huston, JS; Meares, CF; Treves, ST; Packard, AB
    Use of copper radioisotopes in antibody radiolabeling is challenged by reported loss of the radionuclide from the bifunctional chelator used to label the protein. The objective of this study was to investigate the relationship between the thermodynamic stability of the 64Cu-complexes of five commonly used bifunctional chelators (BFCs) and the biodistribution of an antibody labeled with 64Cu using these chelators in tumor-bearing mice. © 2011, Elsevier
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    Positron emission tomography (PET) imaging of neuroblastoma and melanoma with 64Cu-SarAr immunoconjugates
    (National Academy of Sciences, 2007-10-30) Voss, SD; Smith, SV; DiBartolo, N; McIntosh, LJ; Cyr, EM; Bonab, AA; Dearling, JLJ; Carter, EA; Fischman, AJ; Treves, ST; Gillies, SD; Sargeson, AM; Huston, JS; Packard, AB
    The advancement of positron emission tomography (PET) depends on the development of new radiotracers that will complement 18F-FDG. Copper-64 (64Cu) is a promising PET radionuclide, particularly for antibody-targeted imaging, but the high in vivo lability of conventional chelates has limited its clinical application. The objective of this work was to evaluate the novel chelating agent SarAr (1-N-(4-aminobenzyl)-3, 6,10,13,16,19-hexaazabicyclo[6.6.6] eicosane-1,8-diamine) for use in developing a new class of tumor-specific 64Cu radiopharmaceuticals for imaging neuroblastoma and melanoma. The anti-GD2 monoclonal antibody (mAb) 14.G2a, and its chimeric derivative, ch14.18, target disialogangliosides that are overexpressed on neuroblastoma and melanoma. Both mAbs were conjugated to SarAr using carbodiimide coupling. Radiolabeling with 64Cu resulted in >95% of the 64Cu being chelated by the immunoconjugate. Specific activities of at least 10 μCi/μg (1 Ci = 37 GBq) were routinely achieved, and no additional purification was required after 64Cu labeling. Solid-phase radioimmunoassays and intact cell-binding assays confirmed retention of bioactivity. Biodistribution studies in athymic nude mice bearing s.c. neuroblastoma (IMR-6, NMB-7) and melanoma (M21) xenografts showed that 15–20% of the injected dose per gram accumulated in the tumor at 24 hours after injection, and only 5–10% of the injected dose accumulated in the liver, a lower value than typically seen with other chelators. Uptake by a GD2-negative tumor xenograft was significantly lower (<5% injected dose per gram). MicroPET imaging confirmed significant uptake of the tracer in GD-2-positive tumors, with minimal uptake in GD-2-negative tumors and nontarget tissues such as liver. The 64Cu-SarAr-mAb system described here is potentially applicable to 64Cu-PET imaging with a broad range of antibody or peptide-based imaging agents. © 2007, National Academy of Sciences