ABSTRACT
Objective To elucidate the mechanism of radiation resistant effect of LyGDI on NSCLC A549 cells.Methods A549 and H460 cells were irradiated with X-rays of 0,2,4 and 6 Gy.The clone-forming assay was used to detect cell survival and radiosensitivity.The expressions of LyGDI and COX-2 (Cyclooxygenase-2),a key radiosensitivity-related protein,were detected using Western blot.The miR-34 families were analyzed with RT-PCR.50 nmol/L mature miR-34c was transfected into A549 cells.Results The expression levels of LyGDI and COX-2 were much higher in radioresistive A549 cells than that in H460 cells.While the expression of miR-34a was quite low and miR-34b/c was hardly found in both NSCLC cells.Transfection of miR-34c into A549 cells strongly enhanced X-ray induced apoptosis by inhibiting the activations of LyGDI,COX-2,Bcl-2 and p21.Conclusions Up-regulation of LyGDI could induce COX-2 expression.The low expression of miR-34 family might be responsible for the radiation resistance of NSCLC cells.