Phosphatase and tensin homolog overexpression decreases proliferation and invasion and increases apoptosis in oral squamous cell carcinoma cells

Phosphatase and tensin homolog (PTEN) is a potent tumor suppressor which regulates various cellular functions. The aim of the present study was to analyze the function of PTEN gene expression in squamous cell carcinoma (SCC) cells. This gene exhibits a unique function in cell migration and proliferation during the early stages of embryonic development. However, its role as a tumor suppressor gene in tongue squamous carcinoma cells remains unclear. In the present study, an SCC-4 cell line stably expressing PTEN was established and the effects of PTEN gene expression on SCC-4 cell proliferation, invasion and apoptosis were investigated. PTEN expression was found to induce apoptosis in SCC-4 cells, possibly via negative regulation of the phosphatidylinositide 3-kinase/Akt signaling pathway and increased expression of Bcl-2-interacting mediator of cell death. In addition, PTEN was found to control the epithelial-mesenchymal transition in SCC cells, thereby reducing their invasive ability. Furthermore, Transwell assay revealed that the expression of E-cadherin was increased, while the expression of vimentin and SNAIL was decreased. This study has provided an important insight into the mechanisms by which PTEN mediates the progression and early metastasis of tongue carcinoma.