CUDC-907诱导胶质瘤细胞DNA损伤与自噬的实验研究

目的:探讨新型组蛋白去乙酰化酶(histone deacetylase,HDAC)/磷脂酰肌醇3-激酶(phosphatidyl-inositol 3-kinase,PI3K)双靶点抑制剂CUDC-907对人胶质瘤U251细胞DNA损伤、细胞周期及自噬的影响。方法:采用不同浓度的CUDC-907处理U251细胞24 h,MTT法检测细胞活力的变化;激光共聚焦显微镜观察DNA损伤标志物γ-H2AX在细胞内的分布;流式细胞术分析CUDC-907对细胞周期的影响;Western blot实验检测细胞内相关蛋白表达水平的变化。结果:CUDC-907能够抑制U251细胞活力。在CUDC-907处理的细胞中,蛋白激酶B(PKB)/Akt和p70核糖体蛋白S6激酶(p70s6K)的磷酸化水平降低,γ-H2AX的焦点数量与蛋白表达显著升高(P <0.05);U251细胞经CUDC-907作用后,G2/M期细胞数量增多;Western blot实验结果表明,CUDC-907促进p21的表达,同时抑制细胞周期素B1(cyclin B1)的蛋白表达和细胞分裂周期蛋白2(Cdc2)的磷酸化水平(P <0.05);另外,CUDC-907能够诱导细胞自噬,抑制自噬可促进CUDC-907诱导的DNA损伤。结论:CUDC-907能够显著抑制PI3K/Akt信号通路,诱导胶质瘤细胞发生DNA损伤,并阻滞细胞于G_2/M期,同时可诱导胶质瘤细胞发生保护性自噬。

CUDC-907 induces DNA damage and autophagy in glioma cells

AIM:To investigate the effect of CUDC-907, a dual histone deacetylase (HDAC) and phosphatidylinositol 3-kinase (PI3K) inhibitor, on the DNA damage, cell cycle distribution and autophagy in human glioma U251 cells. METHODS:U251 cells were treated with CUDC-907 of different concentrations, and the cell viability was detected by MTT assay. The quantitative γ-H2AX foci were determined by laser scanning confocal microscopy. The cell cycle distribution of U251 cells was examined by flow cytometry. The protein expression was determined by Western blot analysis. RESULTS:CUDC-907 inhibited the cell viability and the phosphorylation of Akt and p70 ribosomal protein S6 kinase (p70s6K) in the U251 cells (P<0.05). In CUDC-907-treated cells, the number of γ-H2AX foci and protein expression of γ-H2AX were increased significantly (P<0.05). CUDC-907 also induced cell arrest in the G₂/M phase by up-regulating the expression of p21, and inhibiting the protein level of cyclin B1 and the phosphorylation of cell division cycle protein 2 (Cdc2). In addition, CUDC-907 triggered cell autophagy, and inhibition of autophagy increased CUDC-907-induced DNA damage of U251 cells. CONCLUSION:CUDC-907 significantly inhibits PI3K/Akt signaling pathway, induces DNA damage and arrests cell cycle in G₂/M phase. Blockage of autophagy promotes CUDC-907-induced DNA damage of U251 cells.