Smac在TRAIL诱导人骨肉瘤Saos-2细胞凋亡中的作用

Role of Smac in TRAIL-induced apoptosis of human osteosarcoma cell Saos-2

目的 :初步研究 Smac在 TNF相关的凋亡诱导配体 (TNF- related apoptosis inducing ligand,TRAIL)诱导的人骨肉瘤 Saos- 2细胞凋亡中的作用。 方法 :观察细胞形态变化和以琼脂糖凝胶电泳分析 TRAIL 作用的 Saos- 2细胞 DNA片段 ,利用流式细胞术及细胞计数法比较 Smac或 Bcl- 2表达不同的细胞的凋亡程度 ,同时以 Western印迹半定量检测细胞胞质内Sm ac表达水平。结果 :Saos- 2细胞在 TRAIL 的作用下出现典型的凋亡样改变。在 TRAIL 作用 Saos- 2细胞时 ,Smac在胞质中的含量明显增加。在 TRAIL 作用 2 4 h后 ,Smac在 Saos- 2细胞中过表达 ,细胞凋亡率由 1 2 .7%增加到 31 .4 %。TRAIL 作用 Saos- 2细胞 4 8h后 ,转染 Bcl- 2的细胞与转染空载体的 Saos- 2细胞相比 ,凋亡率显著降低 (由 2 4 %降至 1 5 % ) ,且胞质中Sm ac的表达水平也明显降低。 结论 :在 TRAIL 诱导的凋亡中 Sm ac起促进作用 ,Bcl- 2可以通过阻止 Sm

Objective:To study the function of Smac in TRAI L induced human osteosarcoma cell Saos 2 apoptosis. Methods: M orphological changes and DNA electrophoresis were used to identify the cell ap optosis. The apoptosis rates were measured by FCM (flow cytometry) and cell coun ting; the Smac expression was detected with Western blotting. Results: TRAIL induced Saos 2 cell apoptosis. During the TRAIL induced apo ptosis, cytosol Smac was significantly increased and the increase could be inhibited by over expressed Bcl 2. After TRAIL treatment for 24 h, the apoptos is rate of Smac over expressed Saos 2 cells increased to 31.4% compared to tha t of control (12.7%). After TRAIL treatment for 48 h, the apoptosis rate of Bcl 2 over expressed Saos 2 cells decreased to 15% compared to that of the control (24%). Conclusion: Smac takes part in the TRAIL induc ed cell apoptosis, and it improves the TRAIL induced cell apoptosis. Bcl 2 may inhibit the cell apoptosis by limiting the Smac release into the cytosol in TRA IL induced cell apoptosis.