The enhancement of radio-sensitivity via autophagy induced by rapamycin with glioma-initiating cells in vivo

To investigate the effect of rapamycin (RPM) on radio-sensitivity of glioma-initiating cells (GICs) in vivo, GICs were inoculated subcutaneously into the NC nude mice. And an intracranial orthotropic model was utilized for evaluation of radio-sensitivity by use of orthotropic injection. Protein levels of LC3 were analyzed with immunoblotting. It was found that tumor inhibition ratio of RPM + IR group was higher than that in control group and IR group. Combination treatment of nude mice bearing intracranial GICs glioma xenografts with rapamycin and IR made a significant increment of animal survival compared with control or IR alone group. Western blot assay showed that the rate of LC3-II/LC3-I increased obviously in combination treatment group among two models. As a conclusion, Rapamycin can enhance the radio-sensitivity of glioma-initiating cells by inducing autophagy in vivo. (authors)