Glycosylation is an important and ubiquitious post-translational modification that is aberrant in cancer. Despite its established importance, it remains relatively poorly understood due to the analytical challenges associated with studying the complex modification in biological samples. Developments in mass spectrometry have enabled the analysis of intact glycopeptides which allows retention of information about both the glycan and modified protein. We have developed glycoproteomic workflows for the analysis of a variety of human clinical samples including tissue and fluid, to provide identification and characterization of protein glycosylation sites.  Our workflow combines enzymatic digestion of proteins, enrichment of glycopeptides using strong anion exchange with electrostatic repulsion hydrophilic interaction chromatography. Samples are then analyzed by LC-MS/MS on an Orbitrap mass spectrometer. In a recent glycopeptide analysis of prostate cancer tissue samples, we identified more than 7000 unique glycopeptides from more than 500 glycoproteins. Thousands of peptides containing complex, and high mannose glycans were identified across samples. Glycans were mapped to specific protein glycosites and substantially more heterogeneity was observed in proteins from prostate cancer tissue compared to adjacent benign tissue. Specific examples of the differences between glycosylation of proteins in cancer and normal prostate tissue will be presented. We have also analyzed protein glycosylation in pancreatic cyst fluid and identified and characterized glycosites on a variety of proteins, including that are pancreatic specific and hint at intriguing underlying biology.

Intact glycopeptide analysis of human tissue and fluid samples for cancer detection

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.