MiR-503 enhances the radiosensitivity of laryngeal carcinoma cells via the inhibition of WEE1.

Enhancing the sensitivity of laryngeal cells to radiation is crucial for improving the efficacy of laryngeal carcinoma. MicroRNAs are known to play a major role in regulating cellular radiosensitivity. This study was designed to explore the effect and the molecular basis of miR-503 in the radiosensitivity of laryngeal carcinoma cells. Quantitative real-time polymerase chain reaction analysis showed that miR-503 expression was decreased in human laryngeal carcinoma cell lines Hep-2 and TU212, and the downregulation of miR-503 was also observed after irradiation. Upregulation of miR-503 by pre-miR-503 transfection restrained proliferation, promoted progression of Hep-2 and TU212 cells through the cell cycle after irradiation, and sensitized cells to radiation. Dual-Luciferase Reporter Assay verified a direct interaction between miR-503 and the WEE1 messenger RNA 3'-untranslated region. The overexpression of miR-503 significantly decreased WEE1 expression at the messenger RNA and protein levels, whereas the inhibition of miR-503 upregulated the expression of WEE1. WEE1 knockdown by WEE1 small interfering RNA apparently abrogated the inhibitory effect of anti-miR-503 on radiosensitivity. In conclusion, miR-503 could function as an enhancer of radiation responses in laryngeal carcinoma cells by inhibiting WEE1, which may be a potential novel radiosensitizing strategy for laryngeal carcinoma.