Abstract | INTRODUCTION: METHODS: Radiolabeling was accomplished with the prosthetic group N-succinimidyl 4-[(18)F]fluorobenzoate ([(18)F]SFB) using both, conventional and microfluidic-based bioconjugation of [(18)F]SFB to N-terminal end of phosphopeptide part of the peptide dimers. Cellular uptake studies in human cancer cell lines HT-29 and FaDu cells at 4 °C and 37 °C and small animal PET in BALB/c mice were utilized for radiopharmacological characterization. RESULTS: Isolated radiochemical yields ranged from 2% to 4% for conventional bioconjugation with [(18)F]SFB. Significantly improved isolated radiochemical yields of up to 26% were achieved using microfluidic technology. Cellular uptake studies of radiolabeled phosphopeptide and phosphopeptide- CPP dimers indicate enhanced internalization of 50% ID/mg protein after 2 h for both phosphopeptide dimers compared to the phosphopeptide alone (<1% ID/mg protein). In vivo biodistribution of (18)F-labeled peptide dimers was determined with small animal PET revealing a superior biodistribution pattern of sC18-containing peptide dimer MQSpTPL-sC18 [(18) F]4. CONCLUSION: ([18)F]SFB labeling of the phosphopeptide- CPP dimers using a microfluidic system leads to an improved chemoselectivity towards the N-terminal NH(2) group compared to the conventional labeling approach. Cell-penetrating peptide sC18 can be considered as an ideal molecular shuttle for intracellular delivery of the Plk1-PBD-binding hexaphosphopeptide as demonstrated by its favourable radiopharmacological profile.
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Authors | Susan Richter, Vincent Bouvet, Melinda Wuest, Ralf Bergmann, Joerg Steinbach, Jens Pietzsch, Ines Neundorf, Frank Wuest |
Journal | Nuclear medicine and biology
(Nucl Med Biol)
Vol. 39
Issue 8
Pg. 1202-12
(Nov 2012)
ISSN: 1872-9614 [Electronic] United States |
PMID | 22784382
(Publication Type: Journal Article)
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Copyright | Copyright © 2012 Elsevier Inc. All rights reserved. |
Chemical References |
- Benzoates
- Cell-Penetrating Peptides
- Fluorine Radioisotopes
- Phosphopeptides
- Radiopharmaceuticals
- Succinimides
- N-succinimidyl-4-fluorobenzoate
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Topics |
- Acylation
- Amino Acid Sequence
- Animals
- Benzoates
(chemistry)
- Cell-Penetrating Peptides
(chemistry)
- Dimerization
- Fluorine Radioisotopes
(chemistry)
- HT29 Cells
- Humans
- Isotope Labeling
- Mice
- Molecular Sequence Data
- Phosphopeptides
(chemistry, metabolism)
- Positron-Emission Tomography
- Protein Transport
- Radiopharmaceuticals
(chemistry, metabolism)
- Succinimides
(chemistry)
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