PET Imaging of a Novel Anxal‐targeted Peptide 18F‐Al‐NODA‐Bn‐p‐SCN‐GGGRDN‐IF7 in A431 Cancer Mouse Models

Annexin 1 (Anxa1) is a highly specific surface marker of tumor vasculature in the lung and prostate solid tumors. The IF7 peptide was modified with a hydrophilic linker, GGGRDN, and coupled with a new bifunctional chelating agent NODA-Bn-p-SCN. The resulting peptides (NODA-Bn-p-SCN-GGGRDN-IF7) were successfully labeled with Al18 F. The targeting characteristics of the radiolabeled peptides were evaluated in the Anxa1 positive A431 tumor model. Micro-PET imaging revealed that the A431 tumors were clearly visualized (5.74 ± 1.13 % ID/g, 3.92 ± 0.78 % ID/g and 1.30 ± 0.43 % ID/g at 0.5h, 1h and 2h post-injection, respectively). Anxa1 binding specificity was also demonstrated by reduced tumor uptake after co-injection with excessive unlabeled GGGRDN-IF7 peptide at 30 min, 60 min, and 120 min post-injection. 18 F-Al-NODA-Bn-p-SCN-GGGRDN-IF7 might be a potential PET imaging agent for detecting Anxa1 levels in cancers due to the favorable characteristics such as convenient synthesis, specific Anxa1 targeting, and good tumor uptakes.