lncRNA MEG3 increases the radiosensitivity of lung cancer cells by regulating miR-21

Objective To investigate the regulatory mechanism of long-chain non-coding RNA (lncRNA) MEG3 on the sensitivity of lung cancer cell line H1299 to irradiation. Methods The expression of MEG3 and miR-21-5p in lung cancer cell line H1299 was detected by qRT-PCR. Overexpression control group (transfected with pcDNA3.1), MEG3 overexpression group (transfected with pcDNA3.1-MEG3), miR-NC inhibition group (transfected anti-miR-NC), miR-21-5p inhibition group (transfected with anti-miR-21-5p), MEG3 overexpression+miR-NC overexpression group (co-transfected with pcDNA3.1-MEG3 and miR-NC), MEG3 overexpression+miR-21-5p overexpression group (co-transfected with pcDNA3.1-MEG3 and miR-21-5p mimics) were all transfected into H1299 cells by liposome method treated with 4Gy irradiation. Cell survival fraction was detected by colony formation assay. Cell apoptosis was detected by flow cytometry. The binding of MEG3 to miR-21-5p in cells was assessed by dual luciferase reporter assay. Results Compared with normal lung epithelial cells, the expression of MEG3 was significantly decreased, whereas the expression of miR-21-5p was significantly increased in the radioresistant lung cancer cells H1299. Overexpression of MEG3 or inhibition of miR-21-5p could promote the apoptosis and enhance the radiosensitivity of H1299 cells. MEG3 could targetedly regulate the expression of miR-21-5p. Overexpression of miR-21-5p could reverse the enhanced radiosensitivity of MEG3 to H1299 cells. Conclusion LncRNA MEG3 can enhance the sensitivity of lung cancer cells H1299 to irradiation. The mechanism may be related to targeting miR-21-5p.