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

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

Volume: 7 Issue: 1

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

Affiliation:

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

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.

Cite this article as:

Zhang Xiuli, Teixeira Vania, Porcal Williams, Cabral Pablo, Gambini Juan-Pablo, Fernandez Marcelo, Gallazzi Fabio and Quinn P. Thomas, [^99mTc(CO)₃]⁺ and [^99mTcO₂]⁺ Radiolabeled Cyclic Melanotropin Peptides for Melanoma SPECT Imaging, Current Radiopharmaceuticals 2014; 7 (1) . https://dx.doi.org/10.2174/1874471007666140715094554