Measuring the Pharmacodynamic Effects of a Novel Hsp90 Inhibitor on HER2/neu Expression in Mice Using 89Zr-DFO-Trastuzumab
| Autor: | Jason S. Lewis, Valerie A. Longo, Tony Taldone, Gabriela Chiosis, Vadim Divilov, Eloisi Caldas-Lopes, Jason P. Holland, Danuta Zatorska |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Mice
Nude Pharmacology Chemistry/Applied Chemistry Deferoxamine Antibodies Monoclonal Humanized HER2/neu Hsp90 inhibitor 03 medical and health sciences Mice 0302 clinical medicine Trastuzumab Cell Line Tumor Medicine Animals Humans Tissue Distribution Benzodioxoles HSP90 Heat-Shock Proteins skin and connective tissue diseases neoplasms 030304 developmental biology 0303 health sciences Multidisciplinary biology business.industry Antibodies Monoclonal Genes erbB-2 3. Good health Cell culture Purines 030220 oncology & carcinogenesis Pharmacodynamics Oncology/Breast Cancer Immunology Monoclonal biology.protein Radiology and Medical Imaging/PET and SPECT Imaging Female Zirconium Antibody Radiology and Medical Imaging/Radionuclide Imaging business medicine.drug Research Article |
| Zdroj: | PLoS ONE |
| ISSN: | 1932-6203 |
| Popis: | Background The positron-emitting radionuclide 89Zr (t 1/2 = 3.17 days) was used to prepare 89Zr-radiolabeled trastuzumab for use as a radiotracer for characterizing HER2/neu-positive breast tumors. In addition, pharmacodynamic studies on HER2/neu expression levels in response to therapeutic doses of PU-H71 (a specific inhibitor of heat-shock protein 90 [Hsp90]) were conducted. Methodology/Principal Findings Trastuzumab was functionalized with desferrioxamine B (DFO) and radiolabeled with [89Zr]Zr-oxalate at room temperature using modified literature methods. ImmunoPET and biodistribution experiments in female, athymic nu/nu mice bearing sub-cutaneous BT-474 (HER2/neu positive) and/or MDA-MB-468 (HER2/neu negative) tumor xenografts were conducted. The change in 89Zr-DFO-trastuzumab tissue uptake in response to high- and low-specific-activity formulations and co-administration of PU-H71 was evaluated by biodistribution studies, Western blot analysis and immunoPET. 89Zr-DFO-trastuzumab radiolabeling proceeded in high radiochemical yield and specific-activity 104.3±2.1 MBq/mg (2.82±0.05 mCi/mg of mAb). In vitro assays demonstrated >99% radiochemical purity with an immunoreactive fraction of 0.87±0.07. In vivo biodistribution experiments revealed high specific BT-474 uptake after 24, 48 and 72 h (64.68±13.06%ID/g; 71.71±10.35%ID/g and 85.18±11.10%ID/g, respectively) with retention of activity for over 120 h. Pre-treatment with PU-H71 was followed by biodistribution studies and immunoPET of 89Zr-DFO-trastuzumab. Expression levels of HER2/neu were modulated during the first 24 and 48 h post-administration (29.75±4.43%ID/g and 41.42±3.64%ID/g, respectively). By 72 h radiotracer uptake (73.64±12.17%ID/g) and Western blot analysis demonstrated that HER2/neu expression recovered to baseline levels. Conclusions/Significance The results indicate that 89Zr-DFO-trastuzumab provides quantitative and highly-specific delineation of HER2/neu positive tumors, and has potential to be used to measure the efficacy of long-term treatment with Hsp90 inhibitors, like PU-H71, which display extended pharmacodynamic profiles. |
| Databáze: | OpenAIRE |
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