The extracellular domain of syndecan-2 regulates the interaction of HCT116 human colon carcinoma cells with fibronectin.

The cell surface heparan sulfate proteoglycan, syndecan-2, is known to play an important role in the tumorigenic activity of colon cancer cells, but the function of its extracellular domain is not yet clear. Cell spreading assays showed that HCT116 human colon cancer cells attached and spread better on fibronectin compared to the other tested extracellular matrixes (ECMs). Notably, syndecan-2 overexpression enhanced the spreading of HCT116 cells on fibronectin, and the opposite effects were observed when syndecan-2 expression was reduced. In addition, an oligomerization-defective syndecan-2 mutant failed to increase cell-ECM interactions and adhesion-related syndecan-2 functions, including migration. Furthermore, analyses using a microfabricated post array detector system revealed that syndecan-2, but not the oligomerization-defective mutant, enhanced the interaction affinity of HCT116 cells on fibronectin. Taken together, these results suggest that the extracellular domain of syndecan-2 regulates the interaction of HCT116 human colon carcinoma cells with fibronectin.