Large-Scale Identification of Core-Fucosylated Glycopeptide Sites in Pancreatic Cancer Serum Using Mass Spectrometry

Glycosylation has significant effects
on protein function and cell
metastasis, which are important in cancer progression. It is of great
interest to identify site-specific glycosylation in search of potential
cancer biomarkers. However, the abundance of glycopeptides is low
compared to that of nonglycopeptides after trypsin digestion of serum
samples, and the mass spectrometric signals of glycopeptides are often
masked by coeluting nonglycopeptides due to low ionization efficiency.
Selective enrichment of glycopeptides from complex serum samples is
essential for mass spectrometry (MS)-based analysis. Herein, a strategy
has been optimized using LCA enrichment to improve the identification
of core-fucosylation (CF) sites in serum of pancreatic cancer patients.
The optimized strategy was then applied to analyze CF glycopeptide
sites in 13 sets of serum samples from pancreatic cancer, chronic
pancreatitis, healthy controls, and a standard reference. In total,
630 core-fucosylation sites were identified from 322 CF proteins in
pancreatic cancer patient serum using an Orbitrap Elite mass spectrometer.
Further data analysis revealed that 8 CF peptides exhibited a significant
difference between pancreatic cancer and other controls, which may
be potential diagnostic biomarkers for pancreatic cancer.