Abstract | OBJECTIVE: This study was to develop a (99m)Tc-labeled alpha-methyl tyrosine (AMT) using L,L-ethylenedicysteine (EC) as a chelator and to evaluate its potential in breast tumor imaging in rodents. METHODS: EC-AMT was synthesized by reacting EC and 3-bromopropyl AMT (N-BOC, ethyl ester) in ethanol/ potassium carbonate solution. EC-AMT was labeled with (99m)Tc in the presence of tin (II) chloride. Rhenium-EC-AMT (Re-EC-AMT) was synthesized as a reference standard for (99m)Tc-EC-AMT. To assess the cellular uptake kinetics of (99m)Tc-EC-AMT, 13 762 rat breast cancer cells were incubated with (99m)Tc-EC-AMT for 0-2 h. To investigate the transport mechanism, the same cell line was used to conduct the competitive inhibition study using L-tyrosine. Tissue distribution of (99m)Tc-EC-AMT was determined in normal rats at 0.5-4 h. Planar imaging of breast tumor-bearing rats was performed at 30 and 90 min. The data were compared with those of (18)F-2-fluoro-2-deoxy-glucose. Blocking uptake study using unlabeled AMT was conducted to investigate the transport mechanism of (99m)Tc-EC-AMT in vivo. RESULTS: Structures of EC-AMT and Re-EC-AMT were confirmed by nuclear magnetic resonance, high performance liquid chromatography and mass spectra. In-vitro cellular uptake of (99m)Tc-EC-AMT in 13,762 cells was increased as compared with that of (99m)Tc-EC and could be inhibited by L-tyrosine. Biodistribution in normal rats showed high in-vivo stability of (99m)Tc-EC-AMT. Planar scintigraphy at 30 and 90 min showed that (99m)Tc-EC-AMT could clearly visualize tumors. (99m)Tc-EC-AMT uptake could be significantly blocked by unlabeled AMT in vivo. CONCLUSION:
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Authors | Fan-Lin Kong, YinHan Zhang, Mohammad S Ali, Chanksok Oh, Richard Mendez, Saady Kohanim, Ning Tsao, Mithu Chanda, Wen-Chien Huang, David J Yang |
Journal | Nuclear medicine communications
(Nucl Med Commun)
Vol. 31
Issue 8
Pg. 699-707
(Aug 2010)
ISSN: 1473-5628 [Electronic] England |
PMID | 20495499
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
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Chemical References |
- Amino Acid Transport Systems
- Chelating Agents
- Organotechnetium Compounds
- ethylene dicysteine
- alpha-Methyltyrosine
- Cysteine
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Topics |
- Amino Acid Transport Systems
(metabolism)
- Animals
- Biological Transport
(drug effects)
- Breast Neoplasms
(diagnostic imaging, metabolism, pathology)
- Cell Line, Tumor
- Chelating Agents
(chemistry)
- Cysteine
(analogs & derivatives, chemistry)
- Female
- Molecular Imaging
(methods)
- Organotechnetium Compounds
(chemical synthesis, chemistry, metabolism, pharmacokinetics)
- Positron-Emission Tomography
- Rats
- alpha-Methyltyrosine
(chemistry, pharmacology)
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