Induction of lysosomal membrane permeabilization by compounds that activate p53-independent apoptosis
Induction of lysosomal membrane permeabilization by compounds that activate p53-independent apoptosis
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DOI：
10.1073/pnas.0408592102
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发表时间：
2005-01-04
影响因子：
11.1
通讯作者：
Linder, S
中科院分区：
文献类型：
--
作者：
Erdal, H;Berndtsson, M;Linder, S
p53蛋白通过多种途径激活细胞死亡程序。由于人类肿瘤中p53突变的高频率被认为导致了对常用化疗药物的耐药性，因此鉴定能诱导不依赖p53的细胞死亡的药物以及明确此类药物的作用机制是很重要的。在此我们筛选了一个药物库（美国国家癌症研究所机制组；879种具有不同作用机制的化合物），并鉴定出175种化合物，它们在培养的HCT116结肠癌细胞中能以小于或等于5μM的浓度诱导细胞角蛋白 - 18的半胱天冬酶裂解。有趣的是，尽管大多数化合物在具有功能性p53的细胞中引发更强的凋亡反应，但在p53缺失的细胞中也观察到显著的凋亡。对15种在诱导凋亡方面对p53表现出弱依赖或不依赖的化合物子集进行了详细研究。在这些化合物中，11种能够在去核细胞中激活半胱天冬酶 - 3。发现7种具有非核靶点的此类化合物可诱导溶酶体膜通透性（LMP）。在用这些药物处理后，观察到溶酶体蛋白酶组织蛋白酶B和组织蛋白酶D向细胞质的转位，并且凋亡被组织蛋白酶D的抑制剂胃蛋白酶抑素A所抑制。凋亡依赖于Bax，这表明LMP诱导了一种线粒体凋亡途径。我们得出结论，大量潜在的抗癌药物可诱导不依赖p53的凋亡，并且LMP是许多此类反应的介质。
The p53 protein activates cellular death programs through multiple pathways. Because the high frequency of p53 mutations in human tumors is believed to contribute to resistance to commonly used chemotherapeutic agents, it is important to identify drugs that induce p53-independent cell death and to define the mechanisms of action of such drugs. Here we screened a drug library (the National Cancer Institute mechanistic set; 879 compounds with diverse mechanisms of actions) and identified 175 compounds that induced caspase cleavage of cytokeratin-18 in cultured HCT116 colon cancer cells at less than or equal to5 muM. Interestingly, whereas most compounds elicited a stronger apoptotic response in cells with functional p53, significant apoptosis was observed also in p53-null cells. A subset of 15 compounds showing weak or no dependence on p53 for induction of apoptosis was examined in detail. Of these compounds, 11 were capable of activating caspase-3 in enucleated cells. Seven such compounds with nonnuclear targets were found to induce lysosomal membrane permeabilization (LMP). Translocation of the lysosomal proteases cathepsin B and cathepsin D into the cytosol was observed after treatment with these drugs, and apoptosis was inhibited by pepstatin A, an inhibitor of cathepsin D. Apoptosis depended on Bax, suggesting that LMP induced a mitochondrial apoptotic pathway. We conclude that a large number of potential anticancer drugs induce p53-independent apoptosis and that LMP is a mediator of many such responses.