Cholecystokinin-B Receptor-Targeted Nanoparticle for Imaging and Detection of Precancerous Lesions in the Pancreas

Survival from pancreatic cancer remains extremely poor, in part because this malignancy is not diagnosed in the early stages, and precancerous pancreatic intraepithelial neoplasia (PanIN) lesions are not seen on routine radiographic imaging. Since the cholecystokinin-B receptor (CCK-BR) becomes over-expressed in PanIN lesions, it may serve as a target for early detection. We developed a biodegradable fluorescent polyplex nanoparticle (NP) that selectively targets the CCK-BR. The NP was complexed to a fluorescent oligonucleotide with Alexa Fluor 647 for far-red imaging and to an oligonucleotide conjugated to Alexa Fluor 488 for localization by immunohistochemistry. Fluorescence was detected over the pancreas of five- to ten-month-old LSL-Kras(G12D/+); P48-Cre (KC) mice only after the injection of the receptor target-specific NP and not after injection of untargeted NP. Ex vivo tissue imaging and selective immunohistochemistry confirmed particle localization only to PanIN lesions in the pancreas and not in other organs, supporting the tissue specificity. A human pancreas tissue microarray demonstrated immunoreactivity for the CCK-BR only in the PanIN lesions and not in normal pancreas tissue. The long-term goal would be to develop this imaging tool for screening human subjects at high risk for pancreatic cancer to enable early cancer detection.