Increasing radiosensitivity with the downregulation of cofilin-1 in U251 human glioma cells.

The aim of the present study was to examine the association between cofilin­1 (CFL1) and radioresistance in human glioma U251 cells. CFL1 expression was downregulated and upregulated in U251 cells through the transfection of CFL1­small interfering (si)RNA and pcDNA3.1­CFL1, respectively. The radiosensitivity of U251 cells and established radioresistant U251 cells (RR­U251) was evaluated using cell viability, migration and invasion ability assays. Cell cycle distribution was also examined. The results showed that CFL1 expression was significantly increased in RR­U251 cells; in addition, the cell viability, migration and invasion ability of RR­U251 cells were significantly enhanced compared to those of the normal U251 cells, whereas the number of cells arrested in G2 phase was markedly decreased. In CFL1­silenced RR­U251 and CFL1­silenced U251 cells, the cell viability, migration and invasion abilities were significantly downregulated and the number of cells arrested in G2 phase was increased compared to that of the untransfected cells. In U251 cells overexpressing CFL1, cell viability, migration and invasion abilities were markedly upregulated and the number of cells arrested in G2 phase was decreased. In conclusion, the results of the present study suggested that downregulation of CFL1 may increase radiosensitivity in U251 cells.