Chemoenzymatic Synthesis of Glycopeptides to Explore the Role of Mucin 1 Glycosylation in Cell Adhesion

• Published in: Chembiochem : a European journal of chemical biology 2023-06, Vol.24 (12), p.e202200741-n/a
• Main Authors: Bello, Claudia, Pranzini, Erica, Piemontese, Emanuele, Schrems, Maximilian, Taddei, Maria Letizia, Giovannelli, Lisa, Schubert, Mario, Becker, Christian F. W., Rovero, Paolo, Papini, Anna Maria
• Format: Article
• Language: English
• Subjects: Adhesion; Cancer; Carcinogenesis; Carcinogens; Cell Adhesion; Cell migration; Glycopeptides; Glycopeptides - chemistry; Glycosylation; Magnetic resonance spectroscopy; Molecular modelling; Mucin; Mucin-1 - chemistry; mucin 1; NMR spectroscopy; Peptides; Peptides - chemistry; Polysaccharides; Proteins; Proteins - metabolism
• ISSN: 1439-4227; 1439-7633
• DOI: 10.1002/cbic.202200741

Post‐translational modifications affect protein biology under physiological and pathological conditions. Efficient methods for the preparation of peptides and proteins carrying defined, homogeneous modifications are fundamental tools for investigating these functions. In the case of mucin 1 (MUC1), an altered glycosylation pattern is observed in carcinogenesis. To better understand the role of MUC1 glycosylation in the interactions and adhesion of cancer cells, we prepared a panel of homogeneously O‐glycosylated MUC1 peptides by using a quantitative chemoenzymatic approach. Cell‐adhesion experiments with MCF‐7 cancer cells on surfaces carrying up to six differently glycosylated MUC1 peptides demonstrated that different glycans have a significant impact on adhesion. This finding suggests a distinct role for MUC1 glycosylation patterns in cancer cell migration and/or invasion. To decipher the molecular mechanism for the observed adhesion, we investigated the conformation of the glycosylated MUC1 peptides by NMR spectroscopy. These experiments revealed only minor differences in peptide structure, therefore clearly relating the adhesion behaviour to the type and number of glycans linked to MUC1. A set of MUC1 glycopeptides was prepared by SPPS implemented by site‐selective chemoenzymatic glycosylation. They were used to investigate the influence of precise MUC1 glycosylation patterns on peptide conformation and on the adhesion of breast cancer cell line MCF‐7. Our studies demonstrate that changes in glycosylation have only small, local effects on peptide structure, while cell‐cell interaction is directly affected by the glycans’ nature and density.