BACKGROUND: (blind field) METHODS: Glioma cell lines (U251, LN229 and LN428) were irradiated with and without Mirin and then clonogenicity, apoptosis, and cell cycle change were examined. Western blot analysis was performed to determine the relative potency of Mirin to inhibit the radioresistance, through the signaling activity of AKT. We also examined the levels of H2AX phosphorylation (γH2AX), which is a marker of DNA double-strand breaks (DSBs) using Western blot. RESULTS: Glioblastoma cells pretreated with Mirin demonstrated an enhanced sensitivity to radiation. FACS analysis revealed that Mirin and radiation caused the glioma cells to accumulate in the G2/M-phase of the cell cycle and the combination of these two treatments further increased the G2/M fraction of the glioma cells. Mirin significantly enhanced radiation-induced apoptotic cell death. Also, Mirin blocked the basal and increase of radiation-induced AKT phosphorylation. We observed that the combination of Mirin and radiation increased persistence of γH2AX at 24 h suggesting the inhibition of DNA DSBs repair. CONCLUSIONS: These results indicate that Mirin can effectively enhance glioma cell radiosensitivity. It suggests that Mirin is a potent radiosensitizer for treating glioma cells. SECONDARY CATEGORY: n/a.