磁性纳米四氧化三铁增强青蒿琥酯诱导的K562细胞凋亡及作用机制研究

本研究旨在观察青蒿琥酯共聚磁性纳米四氧化三铁（MNPs-Fe3O4）后，对K562细胞的细胞毒性效应以及是否增加K562细胞的凋亡，了解MNPs-Fe3O4是否可以增强青蒿琥酯的活性，并进一步探讨其可能的机制。方法:采用Western印迹检测K562细胞Bcl-2、Bax、Bcl-rambo，激活的Caspase-3和Survivin蛋白的表达，应用MTT法检测青蒿琥酯共聚MNPs-Fe3O4后对K562的细胞毒性，用流式细胞仪检测K562细胞的凋亡率。结果:青蒿琥酯可以抑制K562细胞的增殖，当青蒿琥酯共聚MNPs-Fe3O4后，对K562细胞的增殖抑制率显著高于单用青蒿琥酯组（P<0.05），同时检测细胞凋亡率也发现，与单用青蒿琥酯组相比，青蒿琥酯共聚MNPs-Fe3O4组的细胞凋亡率显著增加，结果提示MNPs-Fe3O4可以增强青蒿琥酯的活性。而当加入泛Caspase抑制剂Z-VAD-FMK以后，MNPs-Fe3O4增强青蒿琥酯诱导细胞死亡的效应则被减弱了。Western印迹显示，青蒿琥酯共聚MNPs-Fe3O4组与单用青蒿琥酯组相比，Bcl-2，Bax，Bcl-rambo和Caspase-3蛋白的表达上调，而Survivin蛋白的表达则是下调的。结论:磁性纳米四氧化三铁可以增强青蒿琥酯诱导的K562细胞凋亡，其机制可能与上调Bcl-rambo和下调Survivin蛋白有关。 

Enhancement of the Artesunate-induced Apoptosis of K562 Cells by Magnetic Nanoparticles of Fe3O4 and Their Related Mechanism

To investigate the growth inhibition effect of a copolymer composed of artesunate ( ART ) and magnetic nanoparticles of Fe3O4 ( MNPs-Fe3O4 ) on K562 cells and explore its potential mechanisms. Methods: The protein expression levels of Bcl-2, Bax, Bcl-rambo, Caspase-3, and Survivin in K562 cells treated with or without the copolymer of ART with MNPs-Fe3O4 were measured by Western blot. The cytotoxicity of the copolymer on K562 cells was determined by an MTT assay. The copolymer-induced apoptosis rate of K562 cells was measured by flow cytometry. Results: ART could inhibit the proliferation of K562 cells. When treated with the copolymer of ART with MNPs-Fe3O4, the K562 cell proliferation inhibition rate was significantly increased compared with that of K562 cells treated with ART alone ( P < 0.05 ). Flow cytometry results demonstrated that the apoptosis rate induced by the copolymer more significantly increased than that by ART alone ( P < 0.05 ). These results suggest that MNPs-Fe3O4 can enhance the activity of ART. Interestingly, copolymer-induced cell death was attenuated by the caspase inhibitor Z-VAD-FMK. The results also indicate that when compared with ART alone, the copolymer of MNPs-Fe3O4 and ART up-regulates the expression of Bcl-2, Bax, Bcl-rambo, and Caspase-3 proteins in K562 cells, but down-regulates the expression of Survivin protein. Conclusion: The results suggest that MNPs-Fe3O4 synergistically increases the apoptosis induced by ART in K562 cells, which may be related to the up-regulation of Bcl-rambo and down-regulation of Survivin.