| Imaging of Human Epidermal Growth Factor Receptor Type 2 Expression with 18F-Labeled Affibody Molecule ZHER2:2395 in a Mouse Model for Ovarian Cancer. | |
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MedLine Citation:
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PMID: 22173842 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Affibody molecules are small (7 kDa) proteins with subnanomolar targeting affinity. Previous SPECT studies in xenografts have shown that the Affibody molecule (111)In-DOTA-Z(HER2)(:2395) can discriminate between high and low human epidermal growth factor receptor type 2 (HER2)-expressing tumors, indicating that radiolabeled Affibody molecules have potential for patient selection for HER2-targeted therapy. Compared with SPECT, PET with positron-emitting radionuclides, such as (18)F, may improve imaging of HER2 expression because of higher sensitivity and improved quantification of PET. The aim of the present study was to determine whether the (18)F-labeled NOTA-conjugated Affibody molecule Z(HER2)(:2395) is a suitable agent for imaging of HER2 expression. The tumor-targeting properties of (18)F-labeled Z(HER2)(:2395) were compared with (111)In- and (68)Ga-labeled Z(HER2)(:2395) in mice with HER2-expressing SK-OV-3 xenografts. METHODS: Z(HER2)(:2395) was conjugated with NOTA and radiolabeled with (18)F, (68)Ga, and (111)In. Radiolabeling with (18)F was based on the complexation of Al(18)F by NOTA. The 50% inhibitory concentration values for NOTA-Z(HER2)(:2395) labeled with (19)F, (69)Ga, and (115)In were determined in a competitive cell-binding assay using SK-OV-3 cells. Mice bearing subcutaneous SK-OV-3 xenografts were injected intravenously with radiolabeled NOTA-Z(HER2)(:2395). One and 4 h after injection, PET/CT or SPECT/CT images were acquired, and the biodistribution was determined by ex vivo measurement. RESULTS: The 50% inhibitory concentration values for (19)F-, (69)Ga-, and (115)In-NOTA-Z(HER2)(:2395) were 5.0, 6.3, and 5.3 nM, respectively. One hour after injection, tumor uptake was 4.4 ± 0.8 percentage injected dose per gram (%ID/g), 5.6 ± 1.6 %ID/g, and 7.1 ± 1.4 %ID/g for (18)F-, (68)Ga-, and (111)In-NOTA-Z(HER2)(:2395), respectively, and the respective tumor-to-blood ratios were 7.4 ± 1.8, 8.0 ± 1.3, and 4.8 ± 1.3. Tumor uptake was specific, because uptake could be blocked efficiently by coinjection of an excess of unlabeled Z(HER2)(:2395). PET/CT and SPECT/CT images clearly visualized HER2-expressing SK-OV-3 xenografts. CONCLUSION: This study showed that (18)F-NOTA-Z(HER2)(:2395) is a promising new imaging agent for HER2 expression in tumors. Affibody molecules were successfully labeled with (18)F within 30 min, based on the complexation of Al(18)F by NOTA. Further research is needed to determine whether this technique can be used for patient selection for HER2-targeted therapy. |
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Authors:
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Sandra Heskamp; Peter Laverman; Daniel Rosik; Frederic Boschetti; Winette T A van der Graaf; Wim J G Oyen; Hanneke W M van Laarhoven; Vladimir Tolmachev; Otto C Boerman |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-12-15 |
Journal Detail:
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Title: Journal of nuclear medicine : official publication, Society of Nuclear Medicine Volume: - ISSN: 1535-5667 ISO Abbreviation: - Publication Date: 2011 Dec |
Date Detail:
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Created Date: 2011-12-16 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0217410 Medline TA: J Nucl Med Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Department of Medical Oncology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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