miR-148a promotes cell sensitivity through downregulating SOS2 in radiation-resistant non-small cell lung cancer cells

Non-small cell lung carcinoma (NSCLC) is the most common type of lung cancer; however, radioresistance is a significant barrier in NSCLC radiotherapy. MicroRNA (miR)-148a has been reported to be a tumor suppressor in various types of cancer, including NSCLC. In the present study, the potential role of miR-148a in regulating radiosensitivity of NSCLC cells was investigated. Serum miR-148a expression was evaluated by reverse transcription-quantitative PCR in patients with NSCLC and healthy controls. The effects of miR-148a on cell viability, migration and invasion were assessed by Cell Counting Kit-8 and Transwell assays in radiation-resistant NSCLC cells. Serum miR-148a was downregulated in patients with NSCLC compared with healthy controls and its expression was significantly increased after radiotherapy. By contrast, miR-148a expression was decreased in the radioresistant patients compared with the radiosensitivity patients. Additionally, miR-148a overexpression inhibited the cell proliferation, migration and invasion of radiation-resistant NSCLC cells. In addition, miR-148a had putative binding site with Son of Sevenless 2 (SOS2) and negatively regulated SOS2 expression. Silencing SOS2 expression significantly suppressed miR-148a inhibitor-induced increase in radiosensitivity in NSCLC. In conclusion, the results of the present study suggested that miR-148a could enhance the radiosensitivity of NSCLC cells through targeting SOS2, thus providing potential therapeutic targets to improve radiotherapy in NSCLC.