An 18F-labeled poly(ADP-ribose) polymerase positron emission tomography imaging agent

Poly(ADP-ribose) polymerase (PARP) is involved in repair of DNA breaks\ud and is over-expressed in a wide variety of tumors, making PARP an attractive biomarker for\ud positron emission tomography (PET) and single photon emission computed tomography\ud imaging. Consequently, over the past decade, there has been a drive to develop nuclear\ud imaging agents targeting PARP. Here, we report the discovery of a PET tracer that is based\ud on the potent PARP inhibitor olaparib (1). Our lead PET tracer candidate, [18F]20, was\ud synthesized and evaluated as a potential PARP PET radiotracer in mice bearing\ud subcutaneous glioblastoma xenografts using ex vivo biodistribution and PET−magnetic\ud resonance imaging techniques. Results showed that [18F]20 could be produced in a good\ud radioactivity yield and exhibited specific PARP binding allowing visualization of tumors overexpressing\ud PARP. [18F]20 is therefore a potential candidate radiotracer for in vivo PARP\ud PET imaging.