Caspase-8在TRAIL诱导神经母细胞瘤细胞凋亡中的作用

目的：应用干扰素(IFNγ)诱导神经母细胞瘤（neuroblastoma, NB）细胞caspase 8的表达并观察其是否可以恢复NB细胞对肿瘤坏死因子相关凋亡诱导配体（TRAIL）的敏感性。方法：应用RT PCR方法检测IFNγ作用前后NB细胞caspase-8 mRNA的表达;应用Alamar Blue法及流式细胞术检测IFNγ、TRAIL、IFNγ+TRAIL、IFNγ+caspase-8抑制剂zIETD-FMK+TRAIL对NB细胞生长及凋亡的影响;应用比色法测定NB细胞caspase-8相对活性。结果：对TRAIL敏感的CHP212细胞表达caspase-8,且经IFNγ处理后caspase-8 表达水平逐步增加;对TRAIL不敏感的SY5Y细胞不表达caspase-8,IFNγ作用后其caspase-8 mRNA表达明显增加。IFNγ与TRAIL联用对SY5Y细胞有明显诱导凋亡作用。CHP212细胞caspase-8相对活性随TRAIL作用时间的延长逐步升高;IFNγ与TRAIL联合作用的SY5Y细胞caspase-8相对活性明显高于未加药物处理的对照组、IFNγ组、TRAIL组及抑制剂组。结论：表达caspase-8的NB细胞对TRAIL的诱导凋亡作用敏感,TRAIL诱导NB细胞凋亡过程中伴随caspase-8活性的增加。［中国当代儿科杂志,2010,12(11)：902-907］

Role of caspase-8 in TRAIL-induced apoptosis of neuroblastoma cell lines

Objective The aim of this study was to investigate whether the induction of caspase-8 by γ-interferon(IFNγ) renders neuroblastoma(NB) cells sensitive to tumor necrosis factor related apoptosis inducing ligand(TRAIL).Methods Caspase-8 mRNA expression was determined by RT-PCR .The effects of IFNγ,TRAIL,IFNγ +TRAIL and caspase-8 inhibitor+ TRAIL on the growth and apoptosis of NB cells were detected with the methods of reduction rate of Alamar Blue assay and flow cytometry.The relative caspase-8 activity was measured with colorimetric assay.Results Caspase-8 expression was detectable in CHP212 cells which were sensitive to TRAIL,with an increased expression after treatment with IFNγ.Caspase-8 was undetectable in SH-SY5Y(SY5Y) cells which were resistant to TRAIL,but an increased expression of caspase-8 mRNA was found after treatment with IFNγ.Moreover,TRAIL combined with IFNγ induced apoptosis in SY5Y cells.The relative caspase-8 activity of CHP212 cells increased with the prolonged TRAIL action time.The relative caspase-8 activity of SY5Y cells in the IFNγ+TRAIL group was significantly higher than those of the control,IFNγ,TRAIL and inhibitor groups.Conclusions NB cells expressing caspase-8 are sensitive to TRAIL.TRAIL induces apoptosis in NB cells with an increase of relative caspase-8 activity.