抑制血红素加氧酶-1对三氧化二砷抗胶质瘤的增敏作用

Inhibition of Heme Oxygenase-1 enhances anti-cancer effects of arsenic trioxide on glioma cells

目的探讨抑制血红素加氧酶-1(HO-1)是否可以增强三氧化二砷(ATO)对胶质瘤细胞的氧化损伤作用。方法分别用HO-1激动剂钴原卟啉IX(CoPPIX)和HO-1抑制剂锌原卟啉IX(ZnPPIX)预处理细胞后,用ATO处理胶质瘤细胞系U251MG,通过检测细胞死亡、线粒体膜电位的下降、SubGl等评价ATO对胶质瘤细胞的损伤作用,并使用流式细胞技术检测ATO诱导的活性氧蓄积,用Western blot分析HO-1的诱导、P38和JNK的磷酸化情况。结果 ATO可以诱导U251MG细胞出现明显的细胞死亡、线粒体膜电位(MMP)下降、活性氧蓄积以及HO-1蛋白表达,这些指标均可被活性氧抑制剂L-N-乙酰半胱氨酸(LANC)抑制。HO-1诱导剂CoPPIX可以明显抑制As_2O_3诱导的细胞死亡和活性氧生成,而HO-1抑制剂ZnPPIX则可以显著增强上述作用。结论抑制胶质瘤细胞HO-1的表达能显著增强ATO的抗胶质瘤作用,考虑到HO-1在胶质瘤内高表达,ATO联合HO-1抑制剂可能是一种有效治疗胶质瘤的新方法。

Objective To investigate whether inhibition of heine oxygenase-1 （ HO-I ） may enhance oxidative damage induced by Arsenic trioxide （ATO） in glioma ceils. Methods HO-1 expression or activity in U251MG ceils was modified by its inducer CoPPIX or inhibitor ZnPPIX, then the cells were exposed to ATO treatment. Cell death fraction, mitochondrial membrane potential （MMP） loss,SubG1 population, reactive oxygen species（ROS） generation and phosphorylation ofP38 and JNK were examined to show oxidative damage. Results ATO clearly induced cell death, MMP loss, ROS generation and HO-1 expression in U251MG, which were significantly inhibited by ROS scavenger LNAC. CoPP1X induced HO-1 expression and protected ATO induced cell death and ROS generation, while ZnPPIX had opposite effects. Conclusions HO-1 plays important role against ATO induced oxidative stress. Inhibition of HO-1 has synergistic effects with ATO for glioma treatment.