Deciphering the Metabolic Impact and Clinical Relevance of N-Glycosylation in Colorectal Cancer through Comprehensive Glycoproteomic Profiling.

Colorectal cancer (CRC) progression is driven by complex metabolic alterations, including aberrant N-glycosylation patterns that critically influence tumor development. However, the metabolic and functional roles of N-glycosylation in CRC remain poorly understood. Herein, comprehensive proteomic and N-linked intact glycoproteomics analyses are performed on 45 CRC tumors, and normal adjacent tissues (NATs) are matched, identifying 7125 intact N-glycopeptides from 704 glycoproteins. Through analysis of glycoform expression profiles and structural characteristics, a glycosylation site-protein function association network is constructed to uncover metabolic dysregulation driven by N-glycosylation in CRC. Moreover, an arithmetic model is developed that integrates N-glycan expression patterns, which effectively distinguishes tumors from NATs, reflecting metabolic reprogramming in cancer. These findings identify Chloride Channel Accessory 1 (CLCA1) and Olfactomedin 4 (OLFM4) as potential metabolic biomarkers for CRC diagnosis. Immunohistochemistry and Cox regression analyses validated the prognostic power of these markers. Notably, the critical role of specific N-glycosylation at N196 of Adipocyte plasma membrane-associated protein (APMAP) is highlighted, a key player in tumor metabolism and CRC progression, providing a potential target for therapeutic intervention. These findings offer valuable insights into the metabolic roles of N-glycosylation in CRC, advancing biomarker discovery, enhancing metabolic-based diagnostic precision, and improving personalized treatment strategies targeting cancer metabolism.