Syndecan-1 suppresses epithelial-mesenchymal transition and migration in human oral cancer cells.

Epithelial-mesenchymal transition (EMT) is one of the major processes that contribute to the occurrence of cancer metastasis. EMT has been associated with the development of oral cancer. Syndecan‑1 (SDC1) is a key cell‑surface adhesion molecule and its expression level inversely correlates with tumor differentiation and prognosis. In the present study, we aimed to determine the role of SDC1 in oral cancer progression and investigate the molecular mechanisms through which SDC1 regulates the EMT and invasiveness of oral cancer cells. We demonstrated that basal SDC1 expression levels were lower in four oral cancer cell lines (KB, Tca8113, ACC2 and CAL‑27), than in normal human periodontal ligament fibroblasts. Ectopic overexpression of SDC1 resulted in morphological transformation, decreased expression of EMT‑associated markers, as well as decreased migration, invasiveness and proliferation of oral cancer cells. In contrast, downregulation of the expression of SDC1 caused the opposite results. Furthermore, the knockdown of endogenous SDC1 activated the extracellular signal‑regulated kinase (ERK) cascade, upregulated the expression of Snail and inhibited the expression of E‑cadherin. In conclusion, our findings revealed that SDC1 suppressed EMT via the modulation of the ERK signaling pathway that, in turn, negatively affected the invasiveness of human oral cancer cells. Our results provided useful evidence about the potential use of SDC1 as a molecular target for therapeutic interventions in human oral cancer.