TY - JOUR
T1 - Label-free glycopeptide quantification for biomarker discovery in human sera
AU - Mayampurath, Anoop
AU - Song, Ehwang
AU - Mathur, Abhinav
AU - Yu, Chuan Yih
AU - Hammoud, Zane
AU - Mechref, Yehia
AU - Tang, Haixu
N1 - Publisher Copyright:
© 2014 American Chemical Society.
PY - 2014/11/7
Y1 - 2014/11/7
N2 - Glycan moieties of glycoproteins modulate many biological processes in mammals, such as immune response, inflammation, and cell signaling. Numerous studies show that many human diseases are correlated with quantitative alteration of protein glycosylation. In some cases, these changes can occur for certain types of glycans over specific sites in a glycoprotein rather than on the global abundance of the glycoprotein. Conventional analytical techniques that analyze the abundance of glycans cleaved from glycoproteins cannot reveal these subtle effects. Here we present a novel statistical method to quantify the site-specific glycosylation of glycoproteins in complex samples using label-free mass spectrometric techniques. Abundance variations between sites of a glycoprotein as well as different glycoforms, that is, glycopeptides with different glycans attached to the same site, can be detected using these techniques. We applied our method to an esophageal cancer study based on blood serum samples from cancer patients in an attempt to detect potential biomarkers of site-specific N-linked glycosylation. A few glycoproteins, including vitronectin, showed significantly different site-specific glycosylations within cancer/control samples, indicating that our method is ready to be used for the discovery of glycosylated biomarkers.
AB - Glycan moieties of glycoproteins modulate many biological processes in mammals, such as immune response, inflammation, and cell signaling. Numerous studies show that many human diseases are correlated with quantitative alteration of protein glycosylation. In some cases, these changes can occur for certain types of glycans over specific sites in a glycoprotein rather than on the global abundance of the glycoprotein. Conventional analytical techniques that analyze the abundance of glycans cleaved from glycoproteins cannot reveal these subtle effects. Here we present a novel statistical method to quantify the site-specific glycosylation of glycoproteins in complex samples using label-free mass spectrometric techniques. Abundance variations between sites of a glycoprotein as well as different glycoforms, that is, glycopeptides with different glycans attached to the same site, can be detected using these techniques. We applied our method to an esophageal cancer study based on blood serum samples from cancer patients in an attempt to detect potential biomarkers of site-specific N-linked glycosylation. A few glycoproteins, including vitronectin, showed significantly different site-specific glycosylations within cancer/control samples, indicating that our method is ready to be used for the discovery of glycosylated biomarkers.
KW - biomarker discovery
KW - glycoproteomics
KW - label-free quantification
KW - site-specific glycosylation
UR - http://www.scopus.com/inward/record.url?scp=84908878410&partnerID=8YFLogxK
U2 - 10.1021/pr500242m
DO - 10.1021/pr500242m
M3 - Article
C2 - 24946017
AN - SCOPUS:84908878410
VL - 13
SP - 4821
EP - 4832
JO - Journal of Proteome Research
JF - Journal of Proteome Research
SN - 1535-3893
IS - 11
ER -