Reduced expression of E-cadherin and increased sialylation level in clear cell renal cell carcinoma.

Cancer cells are characterized by an aberrant increase in protein N-glycosylation and by disruption of E-cadherin-mediated adherens junctions. However, the relationship between alterations in N-glycosylation process and loss of E-cadherin adhesion in cancer remains unclear. The mechanisms of altered expression of adhesive glycoproteins in cancer cells have not been fully elucidated. Thus, the aim of this study was to examine the expression of E-cadherin and sialyl Lewisa/x, NeuAcα2-3Gal, NeuAcα2-6Gal/GalNAc structures in the normal renal tissue and intermediate and cancerous tissues from patients with clear cell RCC. Moreover, we attempted to correlate the E-cadherin expression with some specific sugar residues of renal cancer tissue glycoproteins. The expression of E-cadherin was analysed using ELISA test and immunoblotting. Oligosaccharide structures and sialylation level were detected with ELISA test using specific biotinylated lectins or antibodies. A significant decrease of E-cadherin expression as well as a significant increase in sialylated oligosaccharides level in intermediate zone and renal cancer tissue in comparison to normal renal tissue are reported. Significant decrease in expression of cadherins and increase in sialylation of oligosaccharide structures in renal cancer tissue in comparison to normal renal tissue, and in renal cancer tissue in comparison to intermediate zone of renal tissue, are important for the future research concerning detection and quantification of cadherins and sialylated oligosaccharide structures in urine and cells of urinary sediment as possible non-invasive marker of early RCC.