DOTA‐NOC, A high affinity ligand of the somatostatin receptor subtypes 2, 3 and 5 for radiotherapy

Abstract

Abstract The parallel synthesis of DOTA‐octreotide derivatives modified with unnatural amino acids in position 3 of the peptide led to DOTA‐[1‐Nal 3 ]‐octreotide (DOTA‐NOC), which is a high affinity radioligand for three of the five somatostatin receptor subtypes sst2, sst3 and sst5. In internalization experiments with AR42J‐cells and in first biodistributions in tumor bearing Lewis‐rats we showed that DOTA‐NOC is superior to DOTA‐OC and even to DOTA‐TOC. Whereas DOTA‐TOC binds mainly to sst2, DOTA‐NOC is a potential candidate for selective internal radiotherapy of tumors bearing sst2, 3 and 5 receptors.