PARP-Targeted Radiotheranostics with Auger Electrons: An Updated Overview

Auger electrons (AEs) represent an intriguing topic in the field of radionuclide therapy. They are emitted by several radionuclides commonly used in nuclear medicine (indium-111, iodine-123, iodine-125), allowing for highly localized energy deposition and thus exerting a radiotoxic effect on specific cellular and sub-cellular targets. However, due to their short range in matter, AEs have had limited use in therapeutic applications so far. In recent years, the synthesis of various radiopharmaceuticals capable of binding to the enzyme poly(ADP-ribose) polymerase 1 has reignited interest in this type of therapy, laying the groundwork for a theranostic approach based on radionuclides emitting AEs. The enzyme PARP-1 operates enzymatically in close proximity to DNA that represents the prime target of radionuclide therapies. Following this trend, several PARP-targeted radiopharmaceuticals for AE-based theranostics have been developed. We provide an updated overview of preclinical studies focused on the applications of this new theranostic approach in glioblastoma, breast, prostate and ovarian carcinoma, and pancreatic adenocarcinoma.