Apoptosis-inducing factor determines the chemoresistance of non-small-cell lung carcinomas
Apoptosis-inducing factor determines the chemoresistance of non-small-cell lung carcinomas
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DOI：
10.1038/sj.onc.1207835
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发表时间：
2004-08-19
期刊：
影响因子：
8
通讯作者：
Marchetti, P
中科院分区：
文献类型：
--
作者：
Gallego, MA;Joseph, B;Marchetti, P
非小细胞肺癌(NSCLC)对常规抗癌治疗诱导的细胞凋亡具有抵抗力。然而，NSCLC细胞系对广泛的蛋白激酶抑制剂星形孢子素(STS)的作用敏感。在NSCLC细胞系U1810中，STS诱导线粒体释放凋亡诱导因子(AIF)和细胞色素c(Cytc)，继而激活caspase，核固缩，DNA断裂，最终细胞死亡。用广谱caspase抑制剂z-VAD.fmk预先孵育U1810细胞，虽然延缓了STS诱导的核凋亡的发生，但不能阻止线粒体改变(如Cytc和AIF的释放)和细胞死亡的发生。此外，胞浆内注射Cytc或重组活性caspase-3均可促进U1810细胞的核凋亡相关改变。对caspase非依赖因子AIF在STS介导的死亡中的作用的评估表明，当AIF免疫耗竭时，STS处理的U1810的胞浆在与分离的核孵育时失去了诱导核凝集的能力。此外，微量注射抗AIF抗体可以阻止AIF移位到STS处理的U1810细胞的核中，并减少STS诱导的细胞死亡。最后，尽管AIF的过度表达不足以诱导细胞死亡，但它确实增强了STS介导的细胞杀伤。综上所述，这些结果表明caspase的激活不足以杀死U1810细胞，相反，它表明了AIF介导的线粒体介导的死亡途径的重要作用。
Non-small-cell lung carcinomas (NSCLCs) are resistant to the induction of apoptosis by conventional anticancer treatment. However, NSCLC cell lines are sensitive to the action of the broad protein kinase inhibitor, staurosporine (STS). In the NSCLC cell line U1810, STS induced the mitochondrial release of apoptosis-inducing factor (AIF) and cytochrome c (Cyt c) followed by activation of caspases, nuclear condensation, DNA fragmentation and finally cell death. Although preincubation of U1810 cells with the broad-spectrum caspase inhibitor z-VAD.fmk delayed the occurrence of nuclear apoptosis induced by STS, it did not impede mitochondrial alterations (such as the release of Cyt c and AIF) and cell death to occur. Moreover, the microinjection of neither Cyt c nor recombinant active caspase-3 into the cytoplasm promoted nuclear apoptosis-related changes in U1810 cells. Evaluation of the role of the caspase-independent factor AIF in STS-mediated death revealed that, upon immunodepletion of AIF, cytosols from STS-treated U1810 lost their capacity to induce nuclear condensation when incubated with isolated nuclei. In addition, microinjection of an anti-AIF antibody prevented AIF from translocating to the nuclei of STS-treated U1810 cells and reduced STS-induced cell death. Finally, although the transfection-enforced overexpression of AIF was not sufficient to induce cell death, it did enhance STS-mediated cell killing. Altogether, these results indicate that activation of caspases is not sufficient to kill U1810 cells and rather suggests an important role for the AIF-mediated mitochondrial-mediated death pathway.