A novel Tc ‐99 m and fluorescence labeled peptide as a multimodal imaging agent for targeting angiogenesis in a murine tumor model

The serine–aspartic acid–valine (SDV) peptide binds specifically to integrin αVβ3. In the present study, we successfully developed a TAMRA–GHEG–ECG–SDV peptide labeled with both Tc‐99 m and TAMRA to target the integrin αVβ3 of tumor cells; furthermore, we evaluated the diagnostic performance of Tc‐99 m TAMRA–GHEG–ECG–SDV as a dual‐modality imaging agent for tumor of the murine model. TAMRA–GHEG–ECG–SDV was synthesized using Fmoc solid‐phase peptide synthesis. Radiolabeling of TAMRA–GHEG–ECG–SDV with Tc‐99 m was done using ligand exchange methods. Labeling stability and cytotoxicity studies were performed. Gamma camera imaging, biodistribution and ex vivo imaging studies were performed in murine models with HT‐1080 and HT‐29 tumors. A tumor tissue slide was prepared and analyzed using confocal microscopy. After radiolabeling procedures with Tc‐99 m, the Tc‐99 m TAMRA–GHEG–ECG–SDV complexes were prepared in high yield (>99%). In the gamma camera imaging study, a substantial uptake of Tc‐99 m TAMRA–GHEG–ECG–SDV into HT‐1080 tumor (integrin αVβ3 positive) and low uptake of Tc‐99 m TAMRA–GHEG–ECG–SDV into HT‐29 tumor (integrin αVβ3 negative) were demonstrated. A competition study revealed that HT‐1080 tumor uptake was effectively blocked by the co‐injection of an excess concentration of SDV. Specific uptake of Tc‐99 m TAMRA–GHEG–ECG–SDV was confirmed by biodistribution, e...

Source: Contrast Media and Molecular Imaging - June 30, 2016 Category: Radiology Authors: Myoung Hyoun Kim, Chang Guhn Kim, Seul ‐Gi Kim, Dae‐Weung Kim Tags: Full paper Source Type: research