MnSOD模拟化合物通过线粒体途径诱导K562/ADM细胞凋亡

Apoptosis of K562/ADM cells induced by MnSODm through mitochondrial pathway

目的:观察锰超氧化物岐化酶模拟化合物(Mn-SODm)对人白血病K562/ADM耐药细胞凋亡诱导作用,并探讨其分子机制.方法:采用AnnexinV/PI双标记和细胞形态学法检测K562/ADM细胞凋亡;流式细胞术(FCM)检测细胞Bcl-2,Bax蛋白表达水平、线粒体跨膜电位(Δψm),细胞色素C(Cytc)含量和释放Caspase-3活性变化.结果:10,50mg/LMnSODm处理K562/ADM细胞后,AnnexinV/PI染色显示凋亡细胞明显增多,凋亡率分别为85.1%,96.8%;光学显微镜和透射电镜观察呈现典型的凋亡形态改变;FCM检测发现Bcl-2蛋白表达下调32%～73%,Bax蛋白表达增高4～10倍;线粒体Δψm释放降低35%～52%;Cytc含量增高28%～75%;Caspase-3活性增强5.1～6.4倍.结论:MnSODmke可抑制Bcl-2蛋白表达,促进Bax蛋白表达,并通过线粒体途径诱发K562/ADM耐药细胞凋亡.

AIM： To explore the apoptosis-inducing effect of mimics of manganese superoxide dismutase （MnSODm） on human multidrug-resistant leukemia cell line K562/ADM in vitro and the possible molecular mechanisms. METHODS： The apoptosis of K562/ADM cells was assessed with FITC-Annexin V and propidium iodide （PI） double staining and morphological observation. Expressions of Bel-2 and Bax proteins, mitochondrial inner membrane potential （Akl/m）, cytochrome c （Cyt c ） release, and caspase-3 activity were analyzed by flow cytometry （FCM）. RESULTS： After treatment with 10 -50 mg/L MnSODm, the apoptosis rate of K562/ADM cells by Annexin V/PI staining was obviously increased to 85.1% -96.8% , and appearance of typical apoptotic morphological changes of K562/ADM cells was observed by optical and electron microscopes. FCM revealed that the expression of Bcl-2 protein was decreased by 32% -73% and that of Bax protein was increased 4 - 10 times obviously, accom- panied with the disruption of mitochondria △ψm by 35% - 52%, and the increased release of Cyt c by 28% -75% from mitochon- dria to cytoplasm. The activity of caspase-3 was significantly en- hanced by 5.1 - 6.4 times. CONCLUSION： MnSODm down- regulates Bcl-2 protein and up-regulates Bax protein expression, and induces apoptosis of K562/ADM cells through the mitochondrial pathway.