Verrax Julien, Stockis Julie, Tison Aurélie, Taper Henryk S, Calderon Pedro Buc
Unité de Pharmacocinétique, Métabolisme, Nutrition et Toxicologie, Département des sciences pharmaceutiques, Université Catholique de Louvain, Belgium.
Biochem Pharmacol. 2006 Sep 14;72(6):671-80. doi: 10.1016/j.bcp.2006.05.025. Epub 2006 Jul 7.
The effect of oxidative stress induced by the ascorbate/menadione-redox association was examined in K562 cells, a human erythromyeloid leukaemia cell line. Our results show that ascorbate enhances menadione redox cycling, leading to the formation of intracellular reactive oxygen species (as shown by dihydrorhodamine 123 oxidation). The incubation of cells in the presence of both ascorbate/menadione and aminotriazole, a catalase inhibitor, resulted in a strong decrease of cell survival, reinforcing the role of H(2)O(2) as the main oxidizing agent killing K562 cells. This cell death was not caspase-3-dependent. Indeed, neither procaspase-3 and PARP were processed and only a weak cytochrome c release was observed. Moreover, we observed only 23% of cells with depolarized mitochondria. In ascorbate/menadione-treated cells, DNA fragmentation was observed without any sign of chromatin condensation (DAPI and TUNEL tests). The cell demise by ascorbate/menadione is consistent with a necrosis-like cell death confirmed by both cytometric profile of annexin-V/propidium iodide labeled cells and by light microscopy examination. Finally, we showed that a single i.p. administration of the association of ascorbate and menadione is able to inhibit the growth of K562 cells by about 60% (in both tumour size and volume) in an immune-deficient mice model. Taken together, these results reinforced our previous claims about a potential application of the ascorbate/menadione association in cancer therapy.
在人红髓白血病细胞系K562细胞中检测了由抗坏血酸盐/甲萘醌氧化还原联合诱导的氧化应激的影响。我们的结果表明，抗坏血酸盐增强了甲萘醌的氧化还原循环，导致细胞内活性氧的形成（如二氢罗丹明123氧化所示）。在抗坏血酸盐/甲萘醌和过氧化氢酶抑制剂氨基三唑存在的情况下孵育细胞，导致细胞存活率大幅下降，这进一步证明了H₂O₂作为杀死K562细胞的主要氧化剂的作用。这种细胞死亡不依赖于半胱天冬酶-3。事实上，前半胱天冬酶-3和聚（ADP-核糖）聚合酶均未被切割，仅观察到微弱的细胞色素c释放。此外，我们仅观察到23%的细胞线粒体去极化。在抗坏血酸盐/甲萘醌处理的细胞中，观察到DNA片段化，但没有任何染色质凝聚的迹象（DAPI和TUNEL检测）。抗坏血酸盐/甲萘醌导致的细胞死亡与坏死样细胞死亡一致，这通过膜联蛋白-V/碘化丙啶标记细胞的细胞计数分析和光学显微镜检查得到证实。最后，我们表明，在免疫缺陷小鼠模型中，单次腹腔注射抗坏血酸盐和甲萘醌的联合用药能够使K562细胞的生长抑制约60%（肿瘤大小和体积方面）。综上所述，这些结果强化了我们之前关于抗坏血酸盐/甲萘醌联合用药在癌症治疗中潜在应用的主张。
