Glycan-Based Near-infrared Fluorescent (NIRF) Imaging of Gastrointestinal Tumors: a Preclinical Proof-of-Concept In Vivo Study.

ABSTRACT: PURPOSE:Aberrantly expressed glycans in cancer are of particular interest for tumor targeting. This proof-of-concept in vivo study aims to validate the use of aberrant Lewis glycans as target for antibody-based, real-time imaging of gastrointestinal cancers. PROCEDURES:Immunohistochemical (IHC) staining with monoclonal antibody FG88.2, targeting Lewisa/c/x, was performed on gastrointestinal tumors and their healthy counterparts. Then, FG88.2 and its chimeric human/mouse variant CH88.2 were conjugated with near-infrared fluorescent (NIRF) IRDye 800CW for real-time imaging. Specific binding was evaluated in vitro on human gastrointestinal cancer cell lines with cell-based plate assays, flow cytometry, and immune-fluorescence microscopy. Subsequently, mice bearing human colon and pancreatic subcutaneous tumors were imaged in vivo after intravenous administration of 1 nmol (150 ?g) CH88.2-800CW with the clinical Artemis NIRF imaging system using the Pearl Trilogy small animal imager as reference. One week post-injection of the tracer, tumors and organs were resected and tracer uptake was analyzed ex vivo. RESULTS:IHC analysis showed strong FG88.2 staining on colonic, gastric, and pancreatic tumors, while staining on their normal tissue counterparts was limited. Next, human cancer cell lines HT-29 (colon) and BxPC-3 and PANC-1 (both pancreatic) were identified as respectively high, moderate, and low Lewisa/c/x-expressing. Using the clinical NIRF camera system for tumor-bearing mice, a mean tumor-to-background ratio (TBR) of 2.2?±?0.3 (Pearl: 3.1?±?0.8) was observed in the HT-29 tumors and a TBR of 1.8?±?0.3 (Pearl: 1.9?±?0.5) was achieved in the moderate expression BxPC-3 model. In both models, tumors could be adequately localized and delineated by NIRF for up to 1 week. Ex vivo analysis confirmed full tumor penetration of the tracer and low fluorescence signals in other organs. CONCLUSIONS:Using a novel chimeric Lewisa/c/x-targeting tracer in combination with a clinical NIRF imager, we demonstrate the potential of targeting Lewis glycans for fluorescence-guided surgery of gastrointestinal tumors.

SUBMITTER: Houvast RD 

PROVIDER: S-EPMC7666282 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature