Cell-surface glycan-lectin interactions for biomedical applications

Carbohydrate recognition is one of the most sophisticated recognition processes in biological
systems, mediating many important aspects of cell-cell recognition, such as inflammation, cell
differentiation, and metastasis. Consequently, lectin-glycan interactions have been intensively
studied in order to mimic their actions for potential bioanalytical and biomedical applications.
Galectins, a class of ß-galactoside-specific animal lectins, have been strongly implicated in
inflammation and cancer. Galectin-3 is involved in carbohydrate-mediated metastatic cell
heterotypic and homotypic adhesion via interaction with Thomsen-Friedenreich (TF) antigen on
cancer-associated MUC1. However, the precise mechanism by which galectin-3 recognizes TF
antigen is poorly understood. Our thermodynamic studies have shown that the presentation of the
carbohydrate ligand by MUC1-based peptide scaffolds can have a major impact on recognition,
and may facilitate the design of more potent and specific galectin-3 inhibitors that can be used as
novel chemical tools in dissecting the precise role of galectin-3 in cancer and inflammatory
diseases. Another lectin, odorranalectin (OL), has been recently identified from Odorrana grahami
skin secretions as the smallest cyclic peptide lectin, has a particular selectivity for L-fucose and
very low toxicity and immunogenicity, rendering OL an excellent candidate for drug delivery to
targeted sites, such as: (1) tumor-associated fucosylated antigens implicated in the pathogenesis
of several cancers, for overcoming the nonspecificity of most anticancer agents; (2) the olfactory epithelium of nasal mucosa for enhanced delivery of peptide-based drugs to the brain.