Knockdown of lncRNA DLEU1 inhibits the tumorigenesis of oral squamous cell carcinoma via regulation of miR‑149‑5p/CDK6 axis.

Oral squamous cell carcinoma (OSCC) is a frequent malignant tumor worldwide. Long non‑coding RNAs (lncRNAs) are known to play key roles in different types of cancer, including OSCC. It was previously reported that lncRNA deleted in lymphocytic leukemia 1 (DLEU1) is notably upregulated in OSCC; however, the role of DLEU1 in OSCC remains unclear. Gene and protein expression levels in OSCC cells were detected by reverse transcription‑quantitative PCR and western blotting, respectively, in the present study. A Transwell assay was performed to measure cell migration and invasion. Flow cytometry was used to detect cell apoptosis, and the dual‑luciferase reporter assay was applied to confirm the interaction between DLEU1, microRNA (miR)‑149‑5p and CDK6 in OSCC cells. DLEU1 expression was negatively associated with the survival rate of patients with OSCC. In addition, silencing of DLEU1 notably inhibited the proliferation of OSCC cells by inducing apoptosis. Meanwhile, DLEU1 directly bound to miR‑149‑5p, and CDK6 was found to be the direct target of miR‑149‑5p. Furthermore, DLEU1 knockdown‑induced inhibition of OSCC cell proliferation was significantly reversed by the miR‑149‑5p antagomir. Knockdown of lncRNA DLEU1 reversed the proliferation of OSCC cells via regulation of the miR‑149‑5p/CDK6 axis. Thus, DLEU1 may serve as a novel target for treating OSCC.