Characterization of the oligosaccharide component of α 3 β 1 integrin from human bladder carcinoma cell line T24 and its role in adhesion and migration

• Published in: European journal of cell biology Vol. 85; no. 1; pp. 47 - 57
• Main Authors: Pocheć, Ewa, Lityńska, Anna, Bubka, Monika, Amoresano, Angela, Casbarra, Annarita
• Format: Journal Article
• Language: English
• Published: Elsevier GmbH 2006
• Subjects: Cell adhesion; ELISA; Glycosylation; MALDI MS; α3β1 Integrin; FN; PNGase F; Glycosylation; Sia; pNpp; hLN; GnT-V; Col IV; α 3 β 1 Integrin; Gal; S; Fuc; MALDI MS; Cell adhesion; ESH LN; GlcNAc; Man; ELISA
• ISSN: 0171-9335; 1618-1298
• DOI: 10.1016/j.ejcb.2005.08.010

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 α 3 β 1 is particularly interesting because of its role in migration and invasion of several types of metastatic tumours. In this study, α 3 β 1 from human bladder T24 carcinoma cells was purified and treated with peptide N-glycosidase F. Then the N-glycans of the α 3 and β 1 subunits were characterized using matrix-assisted laser desorption ionization mass spectrometry (MALDI MS). In α 3 β 1 integrin the presence of high-mannose, hybrid and predominantly complex type N-oligosaccharides was shown. Unlike to normal epithelium cells, in both subunits of α 3 β 1 integrin from cancer cells, the sialylated tetraantennary complex type glycan Hex 7HexNAc 6FucSia 4 was present. In a direct ligand binding assay, desialylated α 3 β 1 integrin exhibited significantly higher fibronectin-binding capability than untreated integrin, providing evidence that sialic acids play a direct role in ligand-receptor interaction. Moreover, α 3 β 1 integrin was shown to take part in T24 cell migration on fibronectin: anti- α 3 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 α 3 β 1 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.