Quantitative analysis of β1,6GlcNAc-branched N-glycans on β4 integrin in cutaneous squamous cell carcinoma

α6β4 integrin plays pivotal roles in cancer progression in several types of cancers. Our previous study using N-glycan-manipulated cell lines demonstrated that defects in N-glycans or decreased β1,6GlcNAc-branched N-glycans on β4 integrin suppress β4 integrin-mediated cancer cell adhesion, migration, invasion, and tumorigenesis. Furthermore, immunohistochemical analysis has shown that colocalization of β1,6GlcNAc-branched N-glycans with β4 integrin was observed in cutaneous squamous cell carcinoma (SCC) tissue. However, until now there has been no direct evidence that β1,6GlcNAc-branched N-glycans are upregulated on β4 integrin in cutaneous SCC. In the present study, we performed an ELISA analysis of β1,6GlcNAc-branched N-glycans on β4 integrins as well as β4 integrins in cell lysates from human normal skin and cutaneous SCC tissues. The SCC samples showed a 4.9- to 7.4-fold increase in the ratio of β1,6GlcNAc-branched N-glycans to β4 integrin compared with normal skin samples. These findings suggest that the addition of β1,6GlcNAc-branched N-glycans onto β4 integrin was markedly elevated in cutaneous SCC tissue compared to normal skin tissue. The value of β1,6GlcNAc-branched N-glycans on β4 integrin may be useful as a diagnostic marker associated with cutaneous SCC tumor progression.