细胞程序性死亡蛋白5联合阿霉素对人尤文肉瘤细胞凋亡的协同作用及其机制

Recombinant human programmed cell death 5 combined with doxorubicin induced apoptosis of Ewing sarcoma in vitro

目的观察重组细胞程序性死亡蛋白5（rhPDCD5）和阿霉素对人尤文肉瘤细胞株A673的化疗增敏作用，探讨PDCD5在尤文肉瘤化疗中与阿霉素的协调作用机制。方法体外培养人尤文肉瘤细胞株A673，使用噻唑蓝（MTT）法检测实验组（rhPDCD5 10 μg/ml）和对照组对不同浓度梯度阿霉素的增殖抑制表现；流式细胞技术研究A673细胞在rhPDCD5组（rhPDCD5 10 μg/ml）、阿霉素组（1 μmol/L阿霉素）、联合组（rhPDCD5 10 μg/ml＋1 μmol/L阿霉素）的凋亡率；并通过Western blot实验分析rhPDCD5蛋白对尤文肉瘤细胞株凋亡信号通路的调控作用。结果体外培养尤文肉瘤细胞株加入rhPDCD5蛋白后并无明显的凋亡促进作用，而联合使用阿霉素后凋亡率为67.88%，明显高于阿霉素组14.66%；Western blot结果显示rhPDCD5联合阿霉素可明显抑制B细胞淋巴瘤/白血病（bcl）-2、bcl-xl蛋白表达，而增加bcl-2相关X蛋白（bax）和Cleaved Caspase-3的表达，对Bid表达无明显作用。结论PDCD5蛋白单用对尤文肉瘤细胞无明显促凋亡作用，但可明显增加阿霉素化疗敏感性，该作用与上调凋亡蛋白有关。

ObjectiveTo investigate the effect of rhPDCD5 combined with doxorubicin on growth inhibition and apoptosis of human Ewing sarcoma cells in vitro, and to explore its possible mechanism.MethodsEwing sarcoma cell line A673 was treated with rhPDCD5 and/or doxorubicin in vitro. The inhibitory effect of rhPDCD5 combined with doxorubicin on the proliferation of Ewing sarcoma cells was studied by methyl thiazol tetrazolium （MTT） assay. Flow cytometry was used to examine the effect of rhPDCD5 combined with doxorubicin on apoptosis of Ewing sarcoma cells. The expression of B cell lymphoma/leukemia （bcl）-2, bcl-2 associated X protein （bax）, p53, and Cyclin D1 proteins was analyzed by Western blotting.ResultsThe results showed that rhPDCD5 combined with doxorubicin could inhibit tumor proliferation more effectively than doxorubicin alone. The rhPDCD5 combined with doxorubicin could significantly increase apoptosis rate of Ewing sarcoma cells as compared with doxorubicin alone （67.88% vs. 14.66%）. Western blotting revealed that rhPDCD5 combined with doxorubicin could significantly inhibit the expression of bcl-2 and bcl-xl, increase the expression levels of bax and Cleaved Caspase-3, but had no significant effects on Bid.ConclusionOur findings demonstrate that rhPDCD5 plays potential roles in apoptosis of A673 cells induced by doxorubicin, which might be related with the up-regulation of apoptosis-related proteins.