[99mTc(CO)3]+ and [99mTcO2]+ Radiolabeled Cyclic Melanotropin Peptides for Melanoma SPECT Imaging

Author(s): Xiuli Zhang, Vania Teixeira, Williams Porcal, Pablo Cabral, Juan-Pablo Gambini, Marcelo Fernandez, Fabio Gallazzi, Thomas P. Quinn.

Journal Name: Current Radiopharmaceuticals

Volume 7 , Issue 1 , 2014

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Abstract:

The melanoma targeting peptides (Ala-triazol)Ac-Re(Arg11)CCMSH and N4-CO-Re(Arg11)CCMSH were radiolabeled with [99mTc(CO)3]+ and [99mTcO2]+, respectively, and examined for in vitro cell binding, in vivo biodistribution and imaging properties. The (Ala-triazol)Ac-Re(Arg11)CCMSH and N4-CO-Re(Arg11)CCMSH were synthesized as protected peptides on resin followed by rhenium cyclization with [(C6H5)3P]2ReOCl3 in DMF. The peptides were labeled with 99mTc and examined for radiochemical stability and melanoma cell binding. In vivo biodistribution and SPECT/CT imaging studies were performed in B16/F1 melanoma tumor bearing C57 mice. 99mTc(CO)3-(Ala-Triazol)Ac- Re(Arg11)CCMSH and 99mTcO2-N4-CO-Re(Arg11)CCMSH were stable and internalized in B16/F1 melanoma cells upon binding. In vivo biodistribution studies revealed that tumor uptake of 99mTc(CO)3-(Ala-Triazol)Ac-Re(Arg11)CCMSH was 6.08±1.06% ID/g and 7.05±1.48% ID/g at 2 h and 4 h post injection, respectively. Tumor uptake of 99mTcO2-N4-CORe(Arg11)CCMSH was 7.54±1.82% ID/g and 2.28±0.22% ID/g at 1 h and 2 h post injection, respectively. SPECT/CT imaging studies showed that tumor selective uptake of the radiolabeled peptides, which was confirmed by competitive blocking studies.

Keywords: MC1-R, melanoma, peptide, radioimaging, technetium, tetraamine, tricarbonyl.

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Article Details

VOLUME: 7
ISSUE: 1
Year: 2014
Page: [63 - 74]
Pages: 12
DOI: 10.2174/1874471007666140715094554

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