Characterization of the oligosaccharide component of α₃β₁ integrin from human bladder carcinoma cell line T24 and its role in adhesion and migration

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• 作者：Ewa Pocheć ; Anna Lityń ; ska ; Monika Bubka ; Angela Amoresano ; Annarita Casbarra
• 关键词：Cell adhesion ; ELISA ; Glycosylation ; α ; ₃β ; ₁ Integrin ; MALDI MS
• 刊名：European Journal of Cell Biology
• 出版年：2006
• 出版时间：11 January 2006
• 年：2006
• 卷：85
• 期：1
• 页码：47-57
• 全文大小：596 K

文摘

Malignant transformation is highly associated with altered expression of cell surface N-linked oligosaccharides. These changes concern integrins, a family of cell surface glycoproteins involved in the attachment and migration of cells on various extracellular matrix proteins. The integrin α₃β₁ is particularly interesting because of its role in migration and invasion of several types of metastatic tumours. In this study, α₃β₁ from human bladder T24 carcinoma cells was purified and treated with peptide N-glycosidase F. Then the N-glycans of the α₃ and β₁ subunits were characterized using matrix-assisted laser desorption ionization mass spectrometry (MALDI MS). In α₃β₁ integrin the presence of high-mannose, hybrid and predominantly complex type N-oligosaccharides was shown. Unlike to normal epithelium cells, in both subunits of α₃β₁ integrin from cancer cells, the sialylated tetraantennary complex type glycan Hex₇HexNAc₆FucSia₄ was present. In a direct ligand binding assay, desialylated α₃β₁ integrin exhibited significantly higher fibronectin-binding capability than untreated integrin, providing evidence that sialic acids play a direct role in ligand-receptor interaction. Moreover, α₃β₁ integrin was shown to take part in T24 cell migration on fibronectin: anti-α₃ antibodies induced ca 30 % inhibition of wound closure. Treatment of T24 cells with swainsonine reduced the rate of bladder carcinoma cell migration by 16 % , indicating the role of β1,6 branched complex type glycans in this process. Our data show that α₃β₁ integrin function may be altered by glycosylation, that both subunits contribute to these changes, and that glycosylation may be considered a newly found mechanism in the regulation of integrin function.