Nanoparticle PET/CT imaging of natriuretic peptide clearance receptor in prostate cancer

Atrial natriuretic peptide has been recently discovered to have anticancer effects via interaction with cell surface natriuretic peptide receptor A (NPRA) and natriuretic peptide clearance receptor (NPRC). In a preclinical model, NPRA expression has been identified during tumor angiogenesis and may serve as a potential prognostic marker and target for prostate cancer (PCa) therapy. However, the presence of NPRC receptor in the PCa model has not yet been assessed. Furthermore, there is still no report using nanoparticle for PCa positron emission tomography (PET) imaging. Herein, an amphiphilic comb-like nanoparticle was synthesized with controlled properties through modular construction containing C-atrial natriuretic factor (CANF) for NPRC receptor targeting and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator for high specific activity Cu-64 radiolabeling. The pharmacokinetics of ⁶⁴Cu-CANF-Comb exhibited tuned biodistribution and optimized in vivo profile in contrast to the nontargeted ⁶⁴Cu-Comb nanoparticle. PET imaging with ⁶⁴Cu-CANF-Comb in CWR22 PCa tumor model showed high blood pool retention, low renal clearance, enhanced tumor uptake, and decreased hepatic burden relative to the nontargeted ⁶⁴Cu-Comb. Immunohistochemistry staining confirmed the presence of NPRC receptor in tumor tissue. Competitive PET receptor blocking study demonstrated the targeting specificity of ⁶⁴Cu-CANF-Comb to NPRC receptor in vivo. These results establish a new nanoagent for prostate cancer PET imaging.