Triptolide induces lysosomal-mediated programmed cell death in MCF-7 breast cancer cells.
Triptolide induces lysosomal-mediated programmed cell death in MCF-7 breast cancer cells.
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DOI：
10.2147/ijwh.s44074
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Halaby R
中科院分区：
文献类型：
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作者：
Owa C;Messina ME Jr;Halaby R
乳腺癌是导致死亡的主要原因；事实上，按照全球死亡人数排序，这是全世界女性中最常见的癌症类型。本研究旨在探讨雷公藤甲素（一种中药雷公藤提取物）如何诱导 MCF-7 人乳腺癌细胞凋亡。越来越多的证据表明溶酶体蛋白酶在细胞凋亡激活中发挥作用。然而，关于溶酶体蛋白酶直接参与关键的凋亡相关半胱天冬酶的激活和线粒体细胞色素c的释放也存在一些争议。在本研究中，我们证明雷公藤内酯醇会在 MCF-7 细胞中诱导非典型、溶酶体介导的细胞凋亡，因为它们缺乏 caspase-3。通过细胞形态、染色质浓缩、3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四唑溴化物比色细胞生长抑制测定和促凋亡蛋白的表达水平来表征 MCF-7 细胞死亡。进行吖啶橙和 LysoTracker® 染色以观察溶酶体。使用酸性磷酸酶测定和胞质级分中组织蛋白酶 B 蛋白水平的蛋白质印迹监测溶酶体酶活性，结果显示药物处理的细胞中酶活性增加。这些实验表明，雷公藤甲素处理的 MCF-7 细胞经历非典型细胞凋亡，并且在早期阶段，溶酶体酶渗漏到细胞质中，表明溶酶体膜通透性。我们的结果表明，有必要进一步研究雷公藤甲素作为抗癌治疗剂的潜力。
Breast cancer is a major cause of death; in fact, it is the most common type, in order of the number of global deaths, of cancer in women worldwide. This research seeks to investigate how triptolide, an extract from the Chinese herb Tripterygium wilfordii Hook F, induces apoptosis in MCF-7 human breast cancer cells. Accumulating evidence suggests a role for lysosomal proteases in the activation of apoptosis. However, there is also some controversy regarding the direct participation of lysosomal proteases in activation of key apoptosis-related caspases and release of mitochondrial cytochrome c. In the present study, we demonstrate that triptolide induces an atypical, lysosomal-mediated apoptotic cell death in MCF-7 cells because they lack caspase-3. MCF-7 cell death was characterized via cellular morphology, chromatin condensation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric cell growth inhibition assay and the expression levels of proapoptotic proteins. Acridine orange and LysoTracker® staining were performed to visualize lysosomes. Lysosomal enzymatic activity was monitored using an acid phosphatase assay and western blotting of cathepsin B protein levels in the cytosolic fraction, which showed increased enzymatic activity in drug-treated cells. These experiments suggest that triptolide-treated MCF-7 cells undergo atypical apoptosis and that, during the early stages, lysosomal enzymes leak into the cytosol, indicating lysosomal membrane permeability. Our results suggest that further studies are warranted to investigate triptolide’s potential as an anticancer therapeutic agent.