LINC00473 Contributes to the Radioresistance of Esophageal Squamous Cell Carcinoma by Regulating MicroRNA‑497‑5p and Cell Division Cycle 25A

Long non‑coding RNA (lncRNA) LINC00473 plays a carcinogenic role in a variety of different tumor types. Nevertheless, the mechanisms through which LINC00473 regulates the radiosensitivity of esophageal squamous cell carcinoma (ESCC) cells remains elusive. In the present study, reverse transcription‑quantitative PCR was used to quantify the expression of LINC00473, microRNA (miRNA/miR)‑497‑5p and cell division cycle 25A (CDC25A) in ESCC tissues. The association between LINC00473 expression and the clinicopathological characteristics of patients with ESCC was also assessed. Furthermore, Cell Counting kit‑8 and colony formation assays were carried out to monitor the proliferation of ESCC cells exposed to X‑ray radiation. A dual‑luciferase reporter assay was also conducted to analyze the interaction between LINC00473 and miR‑497‑5p, as well as the interaction between CDC25A and miR‑497‑5p. The findings of the present study demonstrated that in ESCC tissues and cells, the expression levels of LINC00473 and CDC25A were significantly upregulated, while the expression of miR‑497‑5p was downregulated. The high expression level of LINC00473 was associated with a higher T stage, lymph node metastasis stage and a lower tumor differentiation grade in patients with ESCC. Following irradiation, transfection with miR‑497‑5p mimics reduced the promoting effect of LINC00473 overexpression on ESCC cell proliferation, and partially impeded the resistance of ESCC cells to X‑ray radiation induced by LINC00473 overexpression. Moreover, transfection with miR‑497‑5p inhibitors partially alleviated the inhibitory effects of LINC00473 knockdown on cellular proliferation, and partly reversed the sensitivity of cells to X‑ray irradiation induced by LINC00473 knockdown. Furthermore, it was confirmed that miR‑497‑5p was able to bind LINC00473 and the 3'‑untranslated region of CDC25A. On the whole, the findings of the present study demonstrate that LINC00473 reduces the radiosensitivity of ESCC cells by modulating the miR‑497‑5p/CDC25A axis.