Terminal N-acetylgalactosamine-containing glycan motifs (Terminal GalNAc motifs)

Terminal N-acetylgalactosamine (GalNAc)-containing glycan motifs are carbohydrate structures characterized by a terminal GalNAc residue, most notably exemplified by the Tn antigen (GalNAcα1-O-Ser/Thr) (Ju et al., 2011, Cancer Glycobiology). These motifs are significant tumor-associated carbohydrate antigens (TACAs) that arise from the truncated O-glycosylation of proteins, a common feature in various epithelial cancers including breast, colon, and prostate cancer (Springer, 1984, Science). The lectin derived from Bauhinia forficata (BfL) specifically recognizes and binds to these terminal GalNAc residues, making it a valuable tool for histochemical diagnosis and a potential scaffold for therapeutic development (Silva et al., 2012, International Journal of Biological Macromolecules). In normal physiological conditions, these GalNAc residues are typically masked by further glycan elongation; however, their exposure in malignant cells facilitates tumor progression, adhesion, and metastasis. Therapeutic strategies targeting these motifs include the use of lectins to induce apoptosis or the development of monoclonal antibodies and CAR-T cells to direct immune responses against cancer cells. Despite their promise, challenges such as the heterogeneity of glycan expression and potential cross-reactivity with low-level expression in normal tissues remain critical considerations in drug development.

Other names

Tn antigenGalNAc-alpha-Ser/ThrTerminal GalNAc glycansTumor-associated carbohydrate antigenN-acetylgalactosamine-containing glycans

Binding to terminal GalNAc residues on cell surface glycoproteins to modulate signaling pathways, induce apoptosis, or facilitate immune-mediated cell lysis.