Wagner Brett A, Britigan Bradley E, Reszka Krzysztof J, McCormick Michael L, Burns C Patrick
Department of Medicine and Radiation Oncology (Free Radical and Radiation Biology Graduate Program), The University of Iowa College of Medicine, Iowa City, IA 52242, USA.
Arch Biochem Biophys. 2002 May 15;401(2):223-34. doi: 10.1016/S0003-9861(02)00053-X.
We set out to identify whether HOCl, which is generated from H(2)O(2) /MPO/Cl(-), is a proximal mediator of H(2)O(2) programmed cell death in the HL-60 human leukemia cell. We found that authentic HOCl induces apoptosis in the HL-60 cell. Both the addition of methionine, an HOCl scavenger, and the removal of Cl(-) from the medium to prevent the formation of HOCl inhibited H(2)O(2)-induced apoptosis. HL-60 cells underwent apoptosis when exposed to HOCl in full medium, which gives rise to chloramines by the reaction of HOCl with amine groups, but not by HOCl in the amine-free HBSS, in which HOCl but not chloramines can be detected. Authentic chloramines induced apoptosis in this cell line in a concentration-dependent manner and at concentrations lower than HOCl. Full medium exposed to HOCl for 24 h would support methionine noninhibitable apoptosis, but did not react with 2-nitro-5-thiobenzoic acid (TNB), raising the possibility that the final inducer is a nonoxidant formed from HOCl and chloramines. We conclude that the signal for apoptosis induced by H(2)O(2) in the MPO-containing HL-60 cell involves the reaction of the diffusible oxidant HOCl with amines producing chloramines and a subsequent non-TNB-reactive product.
我们着手确定由H₂O₂/髓过氧化物酶（MPO）/Cl⁻生成的次氯酸（HOCl）是否是H₂O₂诱导HL-60人白血病细胞程序性细胞死亡的近端介质。我们发现，纯的HOCl可诱导HL-60细胞凋亡。添加HOCl清除剂甲硫氨酸以及从培养基中去除Cl⁻以防止HOCl形成，均能抑制H₂O₂诱导的凋亡。当HL-60细胞在完全培养基中暴露于HOCl时会发生凋亡，HOCl与胺基反应会产生氯胺，但在无胺的汉克斯平衡盐溶液（HBSS）中暴露于HOCl时则不会发生凋亡，在该溶液中可检测到HOCl但检测不到氯胺。纯的氯胺以浓度依赖性方式且在低于HOCl的浓度下诱导该细胞系凋亡。在完全培养基中暴露于HOCl 24小时可支持甲硫氨酸不可抑制的凋亡，但不与2-硝基-5-硫代苯甲酸（TNB）反应，这增加了最终诱导剂是由HOCl和氯胺形成的非氧化剂的可能性。我们得出结论，在含MPO的HL-60细胞中，H₂O₂诱导凋亡的信号涉及可扩散氧化剂HOCl与胺反应生成氯胺以及随后产生的非TNB反应性产物。
