Molecular Imaging of Pancreatic Duct Adenocarcinoma Using a Type 2 Cannabinoid Receptor-Targeted Near-Infrared Fluorescent Probe.

Imaging probes targeting type 2 cannabinoid receptor (CBR) overexpressed in pancreatic duct adenocarcinoma (PDAC) tissue have the potential to improve early detection and surgical outcome of PDAC. The aim of our study was to evaluate the molecular imaging potential of a CBR-targeted near-infrared (NIR) fluorescent probe (NIR760-XLP6) for PDAC. CBR overexpression was observed in both PDAC patient tissues and various pancreatic cancer cell lines. In vitro fluorescence imaging indicated specific binding of NIR760-XLP6 to CBR in human PDAC PANC-1 cells. In a xenograft mouse tumor model, NIR760-XLP6 showed remarkable 50- (ex vivo) and 3.2-fold (in vivo) tumor to normal contrast enhancement with minimal liver and kidney uptake. In a PDAC lymph node metastasis model, significant signal contrast was observed in bilateral axillary lymph nodes with PDAC metastasis after injection of the probe. In conclusion, NIR760-XLP6 exhibits promising characteristics for imaging PDAC, and CBR appears to be an attractive target for PDAC imaging.