[99mTc(CO)3]+ and [99mTcO2]+ radiolabeled cyclic melanotropin peptides for melanoma SPECT imaging.

Abstract

The melanoma targeting peptides (Ala-triazol)Ac-Re(Arg(11))CCMSH and N4-CO-Re(Arg(11))CCMSH were radiolabeled with [(99m)Tc(CO)3](+) and [(99m)TcO2](+), respectively, and examined for in vitro cell binding, in vivo biodistribution and imaging properties. The (Ala-triazol)Ac-Re(Arg(11))CCMSH and N4-CO-Re(Arg(11))CCMSH were synthesized as protected peptides on resin followed by rhenium cyclization with [(C6H5)3P]2ReOCl3 in DMF. The peptides were labeled with (99m)Tc 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. (99m)Tc(CO)3-(Ala-Triazol)Ac- Re(Arg(11))CCMSH and (99m)TcO2-N4-CO-Re(Arg(11))CCMSH were stable and internalized in B16/F1 melanoma cells upon binding. In vivo biodistribution studies revealed that tumor uptake of (99m)Tc(CO)3-(Ala-Triazol)Ac-Re(Arg(11))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 (99m)TcO2-N4-CORe(Arg(11))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.

• Authors: Xiuli Zhang, Vania Teixeira, Williams Porcal, Pablo Cabral, Juan-Pablo Gambini, Marcelo Fernandez, Fabio Gallazzi, Thomas P Quinn
• Journal: Current radiopharmaceuticals (Curr Radiopharm) Vol. 7 Issue 1 Pg. 63-74 ( 2014) ISSN: 1874-4729 [Electronic] United Arab Emirates
• PMID: 25022516 (Publication Type: Journal Article)

Chemical References

• Amines
• Chelating Agents
• Peptides, Cyclic
• Radiopharmaceuticals
• Technetium Compounds
• dioxotechnetium
• Technetium
• Melanocyte-Stimulating Hormones

Topics

• Amines (chemistry)
• Animals
• Binding, Competitive
• Cell Line, Tumor
• Chelating Agents (chemistry)
• Female
• Inhibitory Concentration 50
• Kinetics
• Melanocyte-Stimulating Hormones
• Melanoma (diagnostic imaging)
• Melanoma, Experimental
• Mice
• Mice, Inbred C57BL
• Multimodal Imaging
• Neoplasm Transplantation
• Peptides, Cyclic
• Radiopharmaceuticals
• Technetium
• Technetium Compounds
• Time Factors
• Tissue Distribution
• Tomography, Emission-Computed, Single-Photon
• Tomography, X-Ray Computed (methods)