Silencing of ataxia-telangiectasia mutated by siRNA enhances the in vitro and in vivo radiosensitivity of glioma.

Abstract

It is reported that high expression of the ataxia-telangiectasia mutated (ATM) gene is linked with radioresistance in glioma. We hypothesized that the radiosensitivity of this brain tumor is enhanced by silencing of the ATM gene. We transfected the glioma cell line U251 with the siRNA-ATMpuro (group A) lentivirus or the siRNA-HKpuro (group N, negative control) lentivirus before irradiation. RT-qPCR and western blotting were performed to verify the efficiency of siRNA‑mediated ATM silencing. Expression levels of the ATM gene and protein were obviously downregulated after transfection. Moreover, the expression of the p53, PCNA and survivin genes, which are related to radiosensitivity, was also decreased. CCK-8 and colony formation assays showed lower cell proliferation and survival in group A than in groups N and C (control group that was not transfected with any siRNA). The level of double-stranded DNA breaks was also greater in group A, as determined by the comet tail assay. Flow cytometry showed a higher rate of cell apoptosis and a higher number of cells in the G2 phase in group A. Furthermore, caspase-3, caspase-8 and caspase-9 activity was also higher in group A. In vivo analysis in mouse models created by implantation of the transfected cell lines showed that the amount of necrosis and hemorrhage was higher in group A than that in the control groups. In conclusion, silencing of ATM via the siRNA technique could improve the in vitro and in vivo radiosensitivity of glioma cells.

DOI: 10.3892/or.2016.4754

Cite this paper

@article{Li2016SilencingOA, title={Silencing of ataxia-telangiectasia mutated by siRNA enhances the in vitro and in vivo radiosensitivity of glioma.}, author={Yan Li and Luchun Li and Bo Li and Zhijuan Wu and Yongzhong Wu and Ying Wang and Fu Jin and Dairong Li and Huiwen Ma and Donglin Wang}, journal={Oncology reports}, year={2016}, volume={35 6}, pages={3303-12} }