Biphosphinic palladacycle complex mediates lysosomal-membrane permeabilization and cell death in K562 leukaemia cells
Biphosphinic palladacycle complex mediates lysosomal-membrane permeabilization and cell death in K562 leukaemia cells
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DOI：
10.1016/j.ejphar.2006.06.004
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发表时间：
2006-08-07
影响因子：
5
通讯作者：
Caires, Antonio C. F.
中科院分区：
文献类型：
--
作者：
Barbosa, Christiano M. V.;Oliveira, Carlos R.;Caires, Antonio C. F.
本文用K562白血病细胞系研究了双膦钯络合物（BPC）的细胞毒作用的细胞死亡机制。通过使用3-[4，5-二甲基噻唑-2-基]-2，5-二苯基溴化四氮唑（MTT）和台盼蓝测定，BPC 72小时后K562细胞的IC 50值小于5.0 μ M。使用吖啶橙子活体染色结合荧光显微镜观察到，复合物触发K562细胞凋亡，诱导DNA片段化，如通过电泳分析。在K562细胞中，BPC处理5 h后也观察到溶酶体膜透化，这表明通过质子捕获进行溶酶体内蓄积，因为其pK（a）值范围为5.1 - 6.5。组织蛋白酶B抑制剂[N-（L-3-transpropylcarbamoyl-oxirane-2-carbonyl）-L-isoleucyl-L-proline]（CA 074）可抑制BPC诱导的K562细胞中Caspase-3和Caspase-6活性。这些事件发生在内源性bcl-2和bax表达的存在下。急性毒理学研究表明，BPC在给药（100 mg/kg -i. p.）后14天未对肝脏和肾脏造成损害。BCP处理小鼠的白色和红细胞呈现正常的形态特征。综上所述，这些数据表明，一种新的溶酶体途径的MPC诱导的细胞凋亡，其中溶酶体的主要目标和组织蛋白酶B作为死亡介质。(c)2006 Elsevier B. V.保留所有权利。
The cell death mechanism of cytotoxicity induced by the Biphosphinic Palladacycle Complex (BPC) was studied using a K562 leukaemia cell line. The IC50 values obtained for K562 cells post-72 h of BPC were less than 5.0 mu M by using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and trypan blue assays. Using the Acridine Orange vital staining combining fluorescence microscopy it was observed that the complex triggers apoptosis in K562 cells, inducing DNA fragmentation, as analysed through electrophoresis. Lysosomal-membrane permeabilization was also observed in K562 cells post-5 h of BPC, which suggests intralysossomal accumulation by proton-trapping, since its pK(a) value ranged from 5.1 to 6.5. Caspase-3, and -6 activity induced by BPC in K562 cells was prevented by the cathepsin-B inhibitor [N-(L-3-transpropylcarbamoyl-oxirane-2-carbonyl)-L-isoleucyl-L-proline] (CA074). These events occurred in the presence of endogenous bcl-2 and bax expression. Acute toxicological studies demonstrated that BPC produces no lesions for liver and kidney fourteen-days after drug administration (100 mg/kg - i.p.). White and red blood cells of BPC-treated mice presented normal morphological characteristics. Taken together, these data suggest a novel lysosomal pathway for BPC-induced apoptosis, in which lysosomes are the primary target and cathepsin B acts as death mediator. (c) 2006 Elsevier B.V. All rights reserved.