A novel ¹⁸ F-labeled brain penetrant PET ligand for imaging poly(ADP-ribose) polymerase-1

Area of Science:

• Molecular Biology
• Oncology
• Radiochemistry

Background:

• Poly(ADP-ribose) polymerase-1 (PARP-1) is crucial for DNA repair and a therapeutic target in cancers with homologous recombination deficiency.
• Non-invasive methods to assess PARP-1 expression are limited, hindering treatment optimization.

Purpose of the Study:

• To evaluate [18F]AZD9574, a new positron emission tomography (PET) radiotracer, for its ability to specifically image Poly(ADP-ribose) polymerase-1 (PARP-1) expression.
• To determine the potential of [18F]AZD9574 as a tool for cancer research and monitoring therapeutic response.

Main Methods:

• In vitro testing of [18F]AZD9574 in diverse cancer cell lines (breast, glioblastoma, prostate, pancreatic) to assess uptake and specificity.
• In vivo studies using 22Rv1 xenograft mouse models to evaluate tumor accumulation and biodistribution of the tracer.
• Blocking studies with clinically relevant PARP inhibitors to confirm tracer specificity.

Main Results:

• [18F]AZD9574 uptake in cell lines directly correlated with PARP-1 expression levels.
• Tracer uptake was dose-dependently inhibited by PARP inhibitors, confirming specific binding to PARP-1.
• Significant and specific tumor accumulation of [18F]AZD9574 was observed in mouse models.
• Ex vivo biodistribution studies confirmed organ uptake patterns consistent with specific PARP-1 binding.

Conclusions:

• [18F]AZD9574 is a highly selective PET radiotracer for imaging PARP-1.
• This tracer demonstrates strong potential for non-invasive assessment of PARP-1 expression in cancer.
• [18F]AZD9574 could significantly advance cancer research and personalized therapeutic monitoring.