PET/CT imaging with an 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 ¹⁸F (¹⁸F-labeled galactodendritic unit 4) and examined its potential in imaging urothelial malignancies. Methods: The ¹⁸F-labeled first-generation galactodendritic unit 4 was obtained from its tosylate precursor. We conducted in vivo studies in a galectin-expressing UMUC3 orthotopic BCa model to determine the ability of ¹⁸F-labeled galactodendritic unit 4 to image BCa. Results: Intravesical administration of ¹⁸F-labeled galactodendritic unit 4 allowed specific accumulation of the carbohydrate radiotracer in galectin-1–overexpressing UMUC3 orthotopic tumors when imaged with PET. The ¹⁸F-labeled galactodendritic unit 4 was not found to accumulate in nontumor murine bladders. Conclusion: The ¹⁸F-labeled galactodendritic unit 4 and similar analogs may be clinically relevant and exploitable for PET imaging of galectin-1–overexpressing bladder tumors.