α2,6-linked sialic acids on N-glycans modulate the adhesion of hepatocarcinoma cells to lymph nodes
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The alterations of cell surface sialylation play a key role in tumor metastasis. Enhanced α2,6-sialylation on N-glycans results from overexpression of the sialyltransferase ST6Gal-I. Hca-F and Hca-P cells are murine hepatocarcinoma cell lines which metastasize only to the lymph nodes. Our previous study revealed that ST6Gal-I was involved in the adhesion of Hca-F cells to fibronectin. However, the roles of sialic acids in the adhesion of Hca-F cells to lymph nodes still remain poorly understood. In this study, we observed that expression levels of α2,6-linked sialic acids on Hca-F cells were higher compared to Hca-P cells. Knockdown of ST6Gal-I by small hairpin RNA (shRNA) transfection decreased the expression of α2,6-linked sialic acids and inhibited the adhesion of Hca-F cells to lymph nodes. The adhesion ability was reported to be mediated by siglec-2 which preferentially binds to α2,6-linked sialic acids, and in addition, ST6Gal-I knockdown inhibited the phosphorylated levels of focal adhesion kinase (FAK) and paxillin when cells were treated with siglec-2. Taken together, these results suggest that interaction of α2,6-linked sialic acids with siglec-2 might modulate the adhesion of hepatocarcinoma cells to lymph nodes through the FAK signaling pathway.
Keywordsα2,6-linked sialic acid ST6Gal-I Hepatocarcinoma Adhesion Siglec-2
This work was supported by grants from the Major State Basic Research Development Program of China (2012CB822103), the National Natural Science Foundation of China (31470799, 31170774), and the Program for Liaoning Excellent Talents in University (LJQ2012079).
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