miR-7 enhances radiosensitivity of NSCLC cells. (A) Clonogenic cell survival curves were generated. miR-7 overexpression decreased survival fractions of A549 cells after irradiation (SER=1.54), and inhibition of miR-7 increased the survival fraction (SER=0.89). (B and C) Cell proliferation assays revealed that miR-7-overexpressing cells had decreased viability with (B) time course (0, 24, 48 and 72 h) and (C) increasing radiation dose (0, 2, 4, 6 and 8 Gy) after 2 Gy irradiation. The 24-h time-point was selected as the representative time-point in C. (D) Wound healing (magnification, ×100) and (E) Transwell invasion (magnification, ×400) assays demonstrated that miR-7 combined with irradiation significantly inhibited the migration and invasion of NSCLC cells. *P<0.05, **P<0.01 and ***P<0.001. miR-7, microRNA-7; NSCLC, non-small cell lung cancer; SER, sensitivity enhancement ratio.