High-throughput screening of tumor metastatic-related differential glycoprotein in hepatocellular carcinoma by iTRAQ combines lectin-related techniques.

Glycoproteomics is an important aspect in the research of cancer biomarker discovery. The objective of our study is to screen the profile of serum glycoproteins in hepatocellular carcinoma (HCC) patients and to discover differentially expressed glycoproteins in HCC with or without metastasis. We collected serum from HCC patients and divided them into two groups (non-metastatic HCC group and metastatic HCC group) according to 2002 UICC TNM staging system. Wheat germ agglutinin (WGA) lectin was used to enrich the serum glycoproteins by lectin affinity chromatography. The enriched glycoproteins were labeled with mass-balanced isobaric tags (iTRAQ) and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Two differential glycoproteins were validated by Western blot and biochemical methods, respectively. Fifteen differential serum glycoproteins with WGA affinity were identified (p < 0.05). Among them, nine proteins were up-regulated (>1.5-folds) and six were down-regulated (<0.5-folds) in HCC patients with metastasis. Expression of alpha-1-antitrypsin (SERPINA1) and apolipoprotein A-I (APOA1) was validated by Western blot and biochemical methods, respectively (p < 0.05). Our study has obtained a set of HCC metastasis-associated glycoproteins which may serve as novel prognostic candidates and potential therapeutic targets for HCC metastasis. SERPINA1 might act as a potential glycoprotein biomarker of HCC metastasis.