Effects of triptolide on radiosensitivity of human glioma cells and its mechanism.

Purpose: To study the effect of triptolide (TP) on radiosensitivity of human glioma U251 cells and its mechanism, so as to provide new ideas and methods for the radiotherapy of glioma.

Methods: U251 cells were treated with 10, 50, 100 nmol/L TP at different concentrations and irradiated with 0, 2, 4, 6, 8 Gy X-ray. The radiosensitivity of cells in each group were detected by MTT. U251 cells were then divided into control group, 10 nmol/L TP group, 4 Gy radiation group, 10 nmol/L TP + 4 Gy radiation group. The formation ability of U251 cells in each group was detected by colony formation assay. Flow cytometry was used to detect cell cycle and apoptosis in each group. Western blot was used to detect the changes of PI3K/Akt signal pathway in each group.

Results: When 10, 50, 100 nmol/L TP were combined with 2, 4, 6, 8 Gy X-ray, the proliferation inhibition rate of U251 cells in each group increased significantly (p<0.05); compared with 10 nmol/L TP alone group and 4 Gy radiation alone group, the colony formation ability rate of U251 cells in 10 nmol/L TP + 4Gy radiation combined group decreased significantly (p<0.05), the cell cycle was blocked in G1 phase, and the apoptosis rate was significantly reduced (p<0.05). The level of p-pi3k and p-Akt decreased significantly (p<0.05).

Conclusion: Triptolide could significantly increase the radiosensitivity of human glioma U251 cells and play a role by inhibiting the PI3K/Akt signal pathway.