摘要
目的探讨缺氧条件下TG2在骨肉瘤MG-63细胞凋亡中的作用以及TG2通过阻止细胞色素C的释放和调节Caspase-3的表达及活性抑制细胞凋亡的机制。方法建立骨肉瘤细胞体外缺氧培养模型,设立四组:(1)常氧组;(2)单纯缺氧组;(3)对照si RNA缺氧组;(4)TG2 si RNA缺氧组。观察各组在缺氧培养不同时相(6、12、24、48、72 h)骨肉瘤MG-63细胞TG2、Caspase-3表达、胞核和胞质细胞色素C的变化以及细胞凋亡率。结果与常氧组比较,单纯缺氧组及对照si RNA缺氧组的TG2活性、m RNA及蛋白表达水平明显增强(P<0.01),且随缺氧时间延长明显升高;Caspase-3活性未见明显增加,而Caspase-3及细胞质内细胞色素C蛋白的表达水平和细胞凋亡率轻度增加。与前三组比较,在TG2 si RNA缺氧组,当通过转染TG2 si RNA抑制TG2的表达时,Caspase-3的活性及胞质内细胞色素C蛋白表达水平明显增强(P<0.01);细胞凋亡率也显著增加(P<0.01)。结论缺氧条件下,MG-63骨肉瘤细胞TG2表达增强,并且可以阻止细胞核内细胞色素C向胞质释放,从而降低Caspase-3的表达及活性,抑制肿瘤细胞的凋亡。
Objective To investigate the effect of transgiutaminase2(TG2) on hypoxia-induced apoptosis of osteosarcoma cell line MG-63 and the mechanism of TG2 inhibiting cell apoptosis by suppressing the release of Cytochrome C and regulating the expression and activity of Caspase-3. Methods The hypoxia culture model was established by a hypoxia incubator and divided into four groups, normoxia group, pure hypoxia group, control si RNA hypoxia group and TG2 si RNA hypoxia group. The expression of TG2, Cytochrome C and Caspase-3 as well as the apoptosis rate were observed at different hypoxia culture phases(6, 12, 24, 48, 72h). Microtiter plate assay was performed to monitor intracellular TG2 activity. Results Compared with normoxia group, the activity, m RNA level and protein expression of TG2 were increased remarkably with correspondence to the hypoxia time in the pure hypoxia group and control si RNA hypoxia group(P<0.01). But Caspase-3 activity didn’t change significantly. Similarly, the protein expression level of Caspase-3 and Cytochrome C in cytosol, as well as the apoptosis rate were increased slightly. In the TG2 si RNA hypoxia group, Caspase-3 activity, Cytochrome C protein expression and cell apoptosis rate were increased obviously(P<0.01). Conclusion In the hypoxia condition, TG2 could inhibit the hypoxia-induced apoptosis through preventing Cytochrome C releasing into the cytosol and suppressing Caspase-3 activities.
出处
《肿瘤防治研究》
CAS
CSCD
北大核心
2015年第2期130-135,共6页
Cancer Research on Prevention and Treatment
基金
海南省医药卫生科研项目(14A210267)
国家973计划课题(2002CB513107)
