Inhibition of miR‑21 promotes cell apoptosis in oral squamous cell carcinoma by upregulating PTEN.

MicroRNA‑21 (miR‑21) has been identified as an oncogene and confirmed to serve an important role in carcinogenesis in various types of cancer. However, the effect and mechanism of miR‑21 in oral squamous cell carcinoma (OSCC) has not been fully elucidated. In the present study, miR‑21 inhibitor and empty vector were transfected into OSCC cells, and non‑transfected cells were used as a blank control. The results indicated that when compared with the control and scramble groups, miR‑21 inhibitor suppressed the expression of miR‑21. Conversely, phosphatase and tensin homolog deletion on chromosome 10 (PTEN) was markedly upregulated, and a dual luciferase reporter assay revealed PTEN to be a target gene of miR‑21. Furthermore, miR‑21 inhibitor decreased the proliferation and invasion and enhanced the apoptosis of OSCC cells. There was no significant difference in cell proliferation, invasion and apoptosis between the control and scramble groups. The present data suggested that there may be a regulatory loop between miR‑21 and PTEN, and that miR‑21 inhibition affected the proliferative, invasive and apoptotic abilities of OSCC cells. These findings indicate that miR‑21 may be a possible novel target in the treatment of OSCC.