Knockdown of ST6Gal-I inhibits the growth and invasion of osteosarcoma MG-63 cells

The upregulation of alpha-2,6-sialyltranferase 1 (ST6Gal-I) has been observed in several malignant tumors, including colon, ovarian and liver cancers, where its expression correlates with the invasion and metastasis of these tumors. However, the roles and molecular mechanisms by which ST6Gal-I mediates the growth and invasion of osteosarcoma cells still remain poorly unknown. In this study, we investigated the expression of ST6Gal-I in osteosarcoma MG-63 and Saos-2 cells which have different metastatic potential, and found that ST6Gal-I was highly expressed in MG-63 cells compared to Saos-2 cells. Downregulation of ST6Gal-I by shRNA in MG-63 cells significantly inhibited their malignant behaviors, including in cell proliferation and soft agar colony formation, as well as migration and invasion properties. In addition, we found that ST6Gal-I knockdown inhibited the expression levels of N-cadherin, vimentin, a-SMA, MMP-2, MMP-9 and VEGF. Together, our results suggest a role for ST6Gal-I to promote the growth and invasion of osteosarcoma cells through modulation of EMT-related molecules, and might be a promising marker for the prognosis and therapy of osteosarcoma. (C) 2015 Elsevier Masson SAS. All rights reserved.