Sphingomyelin synthase 1 regulates the epithelial-to-mesenchymal transition mediated by the TGF-β/Smad pathway in MDA-MB-231 cells

Breast cancer is the most common cancer in women and a leading cause of cancer-associated mortalities in the world. Epithelial-to-mesenchymal transition (EMT) serves an important role in the process of metastasis and invasive ability in cancer cells, and transforming growth factor β1 (TGF-β1) have been investigated for promoting EMT. However, in the present study, the role of the sphingomyelin synthase 1 (SMS1) in TGF-β1-induced EMT development was investigated. Firstly, bioinformatics analysis demonstrated that the overexpression of SMS1 negatively regulated the TGFβ receptor I (TβRI) level of expression. Subsequently, the expression of SMS1 was decreased, whereas, SMS2 had no significant difference when MDA-MB-231 cells were treated by TGF-β1 for 72 h. Furthermore, the present study constructed an overexpression cells model of SMS1 and these cells were treated by TGF-β1. These results demonstrated that overexpression of SMS1 inhibited TGF-β1-induced EMT and the migration and invasion of MDA-MB-231 cells, increasing the expression of E-cadherin while decreasing the expression of vimentin. Furthermore, the present study further confirmed that SMS1 overexpression could decrease TβRI expression levels and blocked smad family member 2 phosphorylation. Overall, the present results suggested that SMS1 could inhibit EMT and the migration and invasion of MDA-MB-231 cells via TGF-β/Smad signaling pathway.