Ⅱ型谷氨酰胺转氨酶对缺氧骨肉瘤MG-63细胞凋亡的影响

Effect of Transglutaminase 2 on Apoptosis of MG-63 Cells in Osteosarcoma Under Oxygen-Deficient Environment

目的探讨缺氧条件下骨肉瘤MG-63细胞凋亡与Ⅱ型谷氨酰胺转氨酶(TG2)表达的关系,以及TG2抗凋亡机制与细胞色素C和Caspase-3表达的关系。方法建立骨肉瘤细胞体外缺氧培养模型,设立单纯缺氧组和TG2 siRNA缺氧组,缺氧培养时间为12 h,观察TG2活性、蛋白及mRNA水平,胞核、胞浆中细胞色素C和Caspase-3蛋白水平及细胞凋亡率。结果单纯缺氧组胞核中TG2活性、蛋白及mRNA水平均显著高于TG2 siRNA缺氧组(P<0.05),而胞浆中比较,无显著差异(P>0.05);单纯缺氧组胞核中细胞色素C和Caspase-3蛋白水平显著高于TG2 siRNA缺氧组,胞浆中含量显著低于TG2 siRNA缺氧组(P<0.05);单纯缺氧组的细胞凋亡率显著低于TG2 siRNA缺氧组(P<0.05)。结论缺氧条件下TG2高表达有抑制MG-63骨肉瘤细胞凋亡作用,其机制可能与抑制胞核中细胞色素C和Caspase-3向胞浆中转移有关。

Objective To investigate the relationship between the apoptosis of osteosarcoma MG-63 cells and the expression of type II transglutaminase(TG2)under oxygen-deficient environment,and the relationship between the anti-apoptosis mechanism of TG2 and the expression of cytochrome C and Caspase-3.Methods The hypoxia models of osteosarcoma cells in vitro were established,and then they were divide into single hypoxia group and TG2 siRNA hypoxia group,the hypoxia time was 12h.The levels of TG2 activity,protein and mRNA,levels of cytochrome C and Caspase-3 protein in in nucleus and cytoplasm,and the apoptosis rate of cells were observed.Results The levels of TG2 activity,protein and mRNA expression in nucleus in single hypoxia group were higher than those in the TG2 siRNA hypoxia group(P<0.05),while in cytoplasm had no statistical difference(P>0.05).The levels of cytochrome C and Caspase-3 in nucleus in single hypoxia group were higher than those in the TG2 siRNA hypoxia group(P<0.05),while those in cytoplasm in single hypoxia group were lower than those in the TG2 siRNA hypoxia group(P<0.05).The apoptosis rate of cells in single hypoxia group was significantly lower than that in the TG2 siRNA hypoxia group(P<0.05).Conclusion Under oxygen-deficient environment,the high expression of TG2 can inhibite the apoptosis of MG-63 cells in osteosarcoma,the mechanism may be related to the inhibition of cytochrome C and Caspase-3 transferring nucleus to cytoplasm.