Silencing LncRNA OIP5-AS1 increases radiosensitivity of non-small cell lung cancer A549 cell line by up-regulating miR-34c-5p expression / 中华放射肿瘤学杂志

ABSTRACT

Objective To investigate the effect of LncRNA OIP5-AS1 on radiosensitivity of non-small cell lung cancer (NSCLC) cells and its mechanism.Methods The radiation-resistant cell A549R was established by using A549 cells irradiated by X-ray 6Gy in 5 fractions.The expression levels of OIP5-AS1 and miR-34c-5p in A549 and A549R cells were detected by qRT-PCR.OIP5-AS1 inhibitor or miR-34c-5p mimetic was transfected into A549R cells,or OIP5-AS1 overexpression plasmid was transfected into A549 cells.Cell apoptosis was detected by flow cytometry.Cell radiosensitivity was analyzed by colony formation assay.The expression levels of p-Chk2 and p-ATM proteins were measured by Western blot.Dual luciferase assay was adopted to verify the relationship between OIP5-AS1 and miR-34c-5p.Results Compared with A549 cells,the expression of OIP5-AS1 was significantly up-regulated in A549R cells (1.97±0.11 vs.1.01±0.05,P＜0.05),whereas the expression of miR-34c-5p was remarkably down-regulated (0.43±0.02 vs.1.02±0.06,P＜0.05).The expression levels of p-Chk2 and p-ATM proteins in A549R cells in the silencing OIP5-AS1 +6Gy group were significantly lower (0.43±0.03 vs.1.39±0.15,0.51 ±0.0 5 vs.1.21 ± 0.11,both P＜0.05),whereas the apoptotic rate was significantly higher than those in the silencing control + 6Gy group [(13.29± 1.25)％ vs.(28.47± 2.31)％,P＜0.05)].The expression levels of p-Chk2 and p-ATM proteins in A549 cells in overexpressing OIP5-AS1+6 Gy group were significantly higher than those in overexpression control+6 Gy group (1.23±0.13 vs.0.75±0.06,1.08±0.11 vs.0.59± 0.04,both P＜0.05).Inhibiting miR-34c-5p expression reversed the effect of silencing OIP5-AS1 on survival fraction of A549R cells (SER =1.42).OIP5-AS1 negatively regulated the expression of miR-34c-5p.Conclusion Silencing OIP5-AS1 enhances the radiosensitivity of radiation-resistant A549 cells by up-regulating the expression of miR-34c-5p,providing a potential target for radiotherapy of NSCLC cells.