The Abnormal Glycopatterns of Salivary Glycoproteins in Esophageal Squamous Cell Carcinoma Patients

Jian Shu; Jun Ma; Xiameng Ren; Jian Wang; Yan Wang; Kun Zhang; Hanjie Yu; Xiangqian Guo; Zheng Li

doi:10.3389/fchem.2021.637730

The Abnormal Glycopatterns of Salivary Glycoproteins in Esophageal Squamous Cell Carcinoma Patients

Front Chem. 2021 Mar 4:9:637730. doi: 10.3389/fchem.2021.637730. eCollection 2021.

Authors

Jian Shu¹, Jun Ma^{2

3}, Xiameng Ren¹, Jian Wang⁴, Yan Wang¹, Kun Zhang¹, Hanjie Yu¹, Xiangqian Guo⁵, Zheng Li¹

Affiliations

¹ Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, China.
² Institute of Digestive Disease of Zhengzhou University, Zhengzhou, China.
³ Department of Clinical Laboratory, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
⁴ Department of Oncology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
⁵ Institute of Biomedical Informatics, Cell Signal Transduction Laboratory, Bioinformatics Center, Henan Provincial Engineering Center for Tumor Molecular Medicine, School of Basic Medical Sciences, Henan University, Kaifeng, China.

Abstract

Glycosylation is one of the most crucial posttranslational modifications of proteins, containing a remarkable amount of biological information. The alteration of glycosylation is closely associated with certain diseases. Exploring glyco-code in the development of diseases is a hot topic in recent years. Esophageal squamous cell carcinoma (ESCC) is the primary pathological histology in developing countries and a severe threat to human health. Although the glycan profiles in the blood samples of ESCC patients were analyzed using glycomic and glycoproteomic methods, the difference of salivary glycopatterns between healthy subjects and ESCC patients is not explicit yet. In the present study, ESCC patients (n = 16) and healthy volunteers (HVs, n = 25) were enrolled. The glycomic strategy combining lectin microarray and lectin blotting was employed to investigate and confirm the altered salivary glycopatterns. Datura stramonium (DSA) was selected to isolate the GlcNAc or Galβ1-4GlcNA-containing glycoproteins due to the distinct difference between ESCC patients and HVs. The N-glycans from DSA-enriched glycoproteins were released by PNGase F and further identified by MALDI-TOF/TOF-MS to obtain the precise structural information of the altered glycans. As a result, the glycopatterns recognized by 13 lectins (e.g., ECA, RCA120, and DSA) showed significant alterations in ESCC patients' saliva. The ESCC patients showed higher levels of GalNAc and Gal, sialic acid, and GlcNAc expression profiles and lower levels of mannose and fucose expression profiles. The MALDI-TOF/TOF-MS results indicated that the proportion of the GlcNAc or Galβ1-4GlcNAc-containing N-glycans was increased in ESCC patients (79.04%) compared with HV (63.20%), which was consistent with the results of lectin microarrays. Our findings provide comprehensive information to understand the complex physiological changes in ESCC patients. And the altered salivary glycopatterns such as GlcNAc or Galβ1-4GlcNAc-containing N-glycans recognized by DSA might serve as potential biomarkers for the diagnosis of ESCC patients.

Keywords: MALDI-TOF/TOF-MS; esophageal squamous cell carcinoma; lectin microarrays; protein glycosylation; saliva.