PET/CT imaging with a 18F-labeled galactodendritic unit in a galectin-1 overexpressing orthotopic bladder cancer model

Galectins are carbohydrate-binding proteins overexpressed in bladder cancer (BCa) cells. Dendritic galactose moieties have a high affinity for galectin-expressing tumor cells. We radiolabeled a dendritic galactose carbohydrate with fluorine-18 - (18)F-labeled galactodendritic unit 4 - and examined its potential in imaging urothelial malignancies. Methods: The (18)F-labeled 1st generation galactodendritic unit 4 was obtained from its tosylate precursor. We conducted in vivo studies in galectin-expressing UMUC3 orthotopic BCa model to determine the ability of (18)F-labeled galactodendritic unit 4 to image BCa. Results: Intravesical administration of (18)F-labeled galactodendritic unit 4 allowed specific accumulation of the carbohydrate radiotracer in galectin-1 overexpressing UMUC3 orthotopic tumors when imaged with PET. The (18)F-labeled galactodendritic unit 4 was not found to accumulate in non-tumor murine bladders. Conclusion: The (18)F-labeled galactodendritic unit 4 and similar analogs may be clinically relevant and exploitable for PET imaging of galectin-1 overexpressing bladder tumors.