N-glycosylation of colorectal cancer tissues: a liquid chromatography and mass spectrometry-based investigation

• Published in: Molecular & cellular proteomics 2012-09, Vol.11 (9), p.571-585
• Main Authors: Balog, Crina I A, Stavenhagen, Kathrin, Fung, Wesley L J, Koeleman, Carolien A, McDonnell, Liam A, Verhoeven, Aswin, Mesker, Wilma E, Tollenaar, Rob A E M, Deelder, André M, Wuhrer, Manfred
• Format: Article
• Language: English
• Subjects: Adult; Aged; Biomarkers, Tumor - chemistry; Chromatography, High Pressure Liquid; Colorectal Neoplasms - metabolism; Female; Glycosylation; Humans; Male; Mannose - chemistry; Middle Aged; Polysaccharides - analysis; Polysaccharides - chemistry; Polysaccharides - metabolism; Protein Processing, Post-Translational; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
• ISSN: 1535-9476; 1535-9484
• DOI: 10.1074/mcp.M111.011601

Colorectal cancer is the third most common cancer worldwide with an annual incidence of ~1 million cases and an annual mortality rate of ~655,000 individuals. There is an urgent need for identifying novel targets to develop more sensitive, reliable, and specific tests for early stage detection of colon cancer. Post-translational modifications are known to play an important role in cancer progression and immune surveillance of tumors. In the present study, we compared the N-glycan profiles from 13 colorectal cancer tumor tissues and corresponding control colon tissues. The N-glycans were enzymatically released, purified, and labeled with 2-aminobenzoic acid. Aliquots were profiled by hydrophilic interaction liquid chromatography (HILIC-HPLC) with fluorescence detection and by negative mode MALDI-TOF-MS. Using partial least squares discriminant analysis to investigate the N-glycosylation changes in colorectal cancer, an excellent separation and prediction ability were observed for both HILIC-HPLC and MALDI-TOF-MS data. For structure elucidation, information from positive mode ESI-ion trap-MS/MS and negative mode MALDI-TOF/TOF-MS was combined. Among the features with a high separation power, structures containing a bisecting GlcNAc were found to be decreased in the tumor, whereas sulfated glycans, paucimannosidic glycans, and glycans containing a sialylated Lewis type epitope were shown to be increased in tumor tissues. In addition, core-fucosylated high mannose N-glycans were detected in tumor samples. In conclusion, the combination of HILIC and MALDI-TOF-MS profiling of N-glycans with multivariate statistical analysis demonstrated its potential for identifying N-glycosylation changes in colorectal cancer tissues and provided new leads that might be used as candidate biomarkers.