Overexpression of miRNA-21 promotes radiation-resistance of non-small cell lung cancer

Background: MiRNA-21 was previously reported to be up-regulated in many kinds of cancer. In the present study, we want to investigate the potential role of miRNA-21 in non-small cell lung cancer. Materials and methods: Expression of miRNA-21 was detected in 60 non-small cell lung cancer (NSCLC) samples and adjacent histologically normal tissue using RT-qPCR, Correlation between miRNA-21 expression and clinicopathological features of NSCLC was analyzed using statistical software. The effect of miRNA-21 expression on the growth and apoptosis of A549 cells induced by irradiation was examined. Results: miRNA-21 expression increased in non-small cell lung cancer. Expression of miRNA-21 was positively associated with lymph node metastasis, clinical stage and poor prognosis. Multivariate Cox regression analysis showed that miRNA-21 was an independent prognostic factor for patients. Down-regulation of miRNA-21 inhibited proliferation and cell cycle progress of A549 cells and sensitized cells to radiation. Decreased miRNA-21 expression promoted the apoptosis of A549 cells induced by irradiation. Conclusions: miRNA-21 may be considered as a potential novel target for future development of specific therapeutic interventions in NSCLC.