Long noncoding RNA Lnc‑EGFR promotes cell proliferation and inhibits cell apoptosis via regulating the expression of EGFR in human tongue cancer.

Tongue cancer remains a difficult disease to overcome. Long noncoding RNAs (LncRNAs) have been shown to serve significant roles in the diagnosis and treatment of tongue cancer. Herein, the present study aimed to investigate the role of a newly‑discovered Lnc, Lnc‑EGFR in tongue cancer. The results showed that the transcript level of Lnc‑EGFR was upregulated in patients with tongue cancer and in cultured tongue cancer cell lines. Consistently, expression of EGFR was also elevated selectively in cancerous tissues and malignant cell lines. Knockdown of Lnc‑EGFR inhibited the clonogenic ability and cell viability of human tongue cancer cell lines UM1 and CAL‑27, as evidenced by colony formation assays, and cell proliferation assays. Furthermore, depletion of Lnc‑EGFR in UM1 and CAL‑27 cells increased cell apoptosis by upregulating the activities of caspase‑3, and caspase‑9, but not caspase‑8. Lnc‑EGFR knockdown‑mediated inhibition of clonogenic ability and cell viability was rescued by overexpression of EGFR by adding EGFR recombinant protein into both cell lines. Likewise, Lnc‑EGFR knockdown‑induced cell apoptosis was reversed by co‑treatment with recombinant EGFR protein in UM1 and CAL‑27 cells. All of these results suggested the oncogenic potential of Lnc‑EGFR, which was achieved by positive regulation of EGFR in human tongue cancer.