Oridonin Enhances Radiotherapy Efficacy by Inducing Late-Stage Cell Death and G2/M Arrest in U87MG Glioma Cells

Background: Glioblastoma multiforme is a deadly brain tumor with limited treatment options. The aim of this study was to investigate whether oridonin (OR) could enhance the radiosensitivity of U87MG glioma cancer cells, and compare this effect with that of temozolomide (TMZ).Method: In this experimental study, we investigated the effects of OR on U87MG glioma cells, alone and in combination with radiotherapy and TMZ cell viability assay, cell cycle analysis, and apoptosis assays were performed to assess the impact of these treatments. The differences between groups were assessed using nonparametric tests including Wilcoxon and chi-square using GraphPad Prism software.Results: OR showed dose-dependent cytotoxicity in U87MG glioma cells. Radiation further enhanced the anti-proliferative effect of OR. TMZ, a standard treatment, also showed significant cytotoxicity, especially with radiation. Both treatments induced G2/M cell cycle arrest, particularly when combined with radiation. Notably, OR and radiation caused a more pronounced G2-phase arrest (55.6%) than TMZ (39.9%) (P < 0.001). While neither treatment significantly affected early apoptosis, both increased late-stage cell death. Importantly, OR and radiation significantly increased late-stage cell death (60.07 ± 1.4%) compared with TMZ and radiation alone (48.04 ± 2.9%) (P = 0.02).Conclusion: These findings suggest the potential of OR as a radiosensitizer for Glioblastoma multiforme treatment. Further research is needed to understand the mechanisms and validate these results in living organisms. This paves the way for exploring OR as a radiosensitizer for Glioblastoma multiforme treatment in the future.