神经酰胺通过JNK-c-Jun信号通路诱导胶质瘤细胞自噬性死亡

目的探讨神经酰胺对大鼠脑胶质瘤细胞C6自噬性死亡的影响及其作用机制。方法不同浓度神经酰胺作用于C6细胞后,用MTT法检测细胞的存活率,流式法检测细胞凋亡的改变;Western blotting及电镜的方法观察细胞自噬水平的改变,以及JNK及其下游靶分子c-Jun的磷酸化水平变化;最后进一步借助JNK特异性抑制剂SP600125抑制JNK的活性,观察其对神经酰胺诱导的细胞自噬情况的影响。结果与对照组相比,神经酰胺作用24 h后,C6细胞存活率明显降低,且具有剂量依赖性,差异有统计学意义(P<0.05);与对照组相比,神经酰胺作用24 h后,C6细胞死亡明显升高且具有剂量依赖性,差异有统计学意义(P<0.05),但其中凋亡性死亡比例较低;神经酰胺作用后细胞内自噬小体数目,LC3B/LC3A的比值,Beclin-1的表达水平,以及JNK和c-Jun磷酸化水平都显著升高,差异具有统计学意义(P<0.05);提前给予JNK特异性抑制剂SP600125抑制JNK的活性后,显著阻断神经酰胺诱导的细胞自噬。结论神经酰胺可诱导胶质瘤细胞C6发生自噬性死亡,其诱导胶质瘤细胞发生自噬的机制可能与激活JNK信号通路有关。

Ceramide induces autophagic cell death in glioma cell through JNK-c-Jun pathway

Objective To observe the autophagy of glioma cell induced by ceramide and explore the possible mechanism. Methods The viability of C6 cells was measured by MTT assay. The cell apoptosis was assayed by flow cytometry. Autophagic-related protein expressions of LC3B/LC3A and Beclin-1 were determined by Western blotting. The level of JNK-c-Jun induced by ceramide was measured by Western blotting with or without the treatment of JNK specific inhibitor SP600125. Results After treatment of ceramide for 24 hours, the growth of C6 cells were significantly inhibited in dose-dependent manner(P<0.05); and ceramide increased autophagic cell death also in dose-dependent manner(P<0.05). Compared with the control group, the levels of LC3B/LC3A and Beclin-1 were significantly increased in ceramide treatment group(P<0.05). JNK was activated in the C6 cells exposed to ceramide and the phosphorylation of c-Jun also increased. This activation of autophagy could be reversed by the pre-treatment of SP600125. Conclusion Ceramide may induce autophagy in glioma cell and the mechanism may be related to the activation of JNK-c-Jun signaling pathway.