Catch and Release Radiolabeled Peptides: a new technology for radiotracer development

PROJECT SUMMARY Radiolabeled peptides are emerging as a very valuable class of radiotracers that are seated in a unique chemical space, exploiting many of the advantages of small molecules and large biomolecules. To date, they have mostly been used in the oncology field for imaging and treatment. Important to note that peptides are widely sought in drug development for the same reasons. This mass appeal is mostly in part to the high density of chirality and functionality that peptides possess as well as their ease of synthesis which has significantly benefited from automation. In addition, several technologies exist, like one-bead-one-compound libraries and phage display approaches that render discovering biologically-relevant, target-specific peptides quite easy. A new twist on some very old chemistry has paved the way for a new technology in the radiolabeling of peptides that yields high purity, high molar activity tracers in biologically compatible formulation without need for costly reconstitution and purification steps, and can potentially be fully integrated into existing automated peptide synthesis. A technology like this would tremendously benefit the synthesis, evaluation and clinical translation of peptide radiotracers. Beyond this, however, this technology offers new opportunities to integrate positron emission labeled molecules in drug discovery and pharmacology. A robust and automated platform to radiolabel a richly diverse class of molecules could be used to assess collections of molecules in single molecular interactions, in cells and in living biological systems. The goal of this proposal is the development of a new radiolabeling technical platform for peptides and apply it to a group of phage-selected antimicrobial peptides. The study of this group of labeled compounds will be conducted in parallel to assist in the discovery of new biologically-relevant, target-specific peptides, as well as, gaining fundamental understanding of the structure and function relationships of groups of peptides. The information gathered from this project will play in important role in the development of new imaging agents and therapies.