The impact of X-rays on the expressions of miR-130a/miR-25 and its potential role in the enhanced metastasis of A549 cell lines in vitro induced by X-rays

We aimed to investigate the impact of X-rays on miR-130a and miR-25 expressions of A549 cell lines and to understand the mechanism of miR-130a and miR-25 on the regulation of invasion and metastasis of A549 cell lines. Human adenocarcinoma cells of the line A549 were cultured and radiated by X-rays at the absorbed doses of 2 and 4, respectively by linear accelerator. Transwell invasion and migration assay were employed to exam the metastasis ability of A549 cells post X-rays irradiation. Both the miRNA and mRNA were extracted from A549 cells at different time points post radiation. The expressions of miR-130a and miR-25, as well as the expressions of VEGF and CCR-7 mRNAs, were detected in A549 cells with 2 and 4 Gy X-rays radiation, respectively by real time PCR. Results were statistically analyzed by SAS 8.2 software, which showed that the invasiveness of A549 cells post 2 and 4 Gy X-rays increased significantly compared with that of untreated A549 cells (the migration cell numbers are 20, 48 and 62 in Group 0, 2 and 4 Gy X-rays, respectively). Furthermore, the expressions of miR-130a and miR-25 also increased significantly at the time-points of 1, 2, 4, and 8 h post radiation, and began to decrease to the control level at 12 h post radiation. VEGF and CCR-7 mRNAs were detected to be up-regulated 18 h post radiation and remained at a high level till 72 h post radiation. The expression of VEGF mRNA has a close correlation with that of CCR-7 mRNA, and the expression of miR-130a also has a correlation with that of VEGF and CCR-7mRNAs. It is concluded that the metastasis of A549 cells in vitro could be promoted by X-rays, and miR-130a might play a role in the metastasis of A549 cells via regulating the expressions of VEGF and CCR-7 mRNAs.