Altered glycosylation associated with dedifferentiation of hepatocellular carcinoma: a lectin microarray-based study

BACKGROUND: Altered glycosylation associated with hepatocellular carcinoma (HCC) is well documented. However, few reports have investigated the association between dedifferentiation and glycosylation. Therefore, the aim of this study was to analyze glycosylation associated with dedifferentiation of HCC within the same nodule and to investigate glycosyltransferase related to the glycosylation. METHODS: We analyzed resected HCC specimens (n = 50) using lectin microarray to comprehensively and sensitively analyze glycan profiles, and identify changes to glycosylation between well- and moderately-differentiated components within the same nodule. Moreover, we performed immunohistochemical staining of mannosyl(α-1,3-)-glycoprotein β-1,2-N-acetylglucosaminyltransferase (MGAT1), which is an essential glycosyltransferase that converts high-mannose glycans to complex- or hybrid-type N-glycans. RESULTS: Four lectins from Narcissus pseudonarcissus agglutinin (NPA), Concanavalin A, Galanthus nivalis agglutinin, and Calystegia sepium agglutinin were significantly elevated in moderately-differentiated components of HCC compared with well-differentiated components, and all lectins showed binding specificity to high-mannose glycans. Therefore, these structures were represented to a greater extent in moderately-differentiated components than in well-differentiated ones. Immunohistochemical staining revealed significantly increased NPA expression and decreased MGAT1 expression in moderately-differentiated components. Low MGAT1 expression in moderately-differentiated components of tumors was associated with intrahepatic metastasis and had tendency for poor prognosis. CONCLUSION: Dedifferentiation of well-differentiated HCC is associated with an increase in high-mannose glycans. MGAT1 may play a role in the dedifferentiation of HCC.