Ferreira C G, Tolis C, Span S W, Peters G J, van Lopik T, Kummer A J, Pinedo H M, Giaccone G
Division of Medical Oncology, University Hospital Vrije Universiteit Amsterdam, The Netherlands.
Clin Cancer Res. 2000 Jan;6(1):203-12.
Anticancer drugs exert at least part of their cytotoxic effect by triggering apoptosis. We previously identified chemotherapy-induced apoptosis in lung cancer cells and suggested a role for p53 alternative or complementary pathways in this process. Recently, a role for the Fas/FasL (CD95/Apo1) signaling system in chemotherapy-induced apoptosis was proposed in some cell types. In the present work, the involvement of the Fas/FasL system in drug-induced apoptosis in lung cancer cells was investigated upon exposure to four cytotoxic drugs (cisplatin, gemcitabine, topotecan, and paclitaxel). We assessed the expression of Fas and FasL and the function of the Fas pathway in six lung cancer cell lines (H460, H322, GLC4, GLC4/ADR, H187, and N417). All lung cancer cell lines expressed Fas and FasL at RNA and protein levels, and apoptosis could be induced in four of six cell lines upon exposure to the Fas agonistic monoclonal antibody (mAb) CLB-CD95/15. Nevertheless, after drug exposure, no significant FasL up-regulation was observed, whereas the Fas expression was increased in the wild-type p53 cell line H460, but not in the other lines, proved to be mutant p53 by direct gene sequencing. Moreover, no correlation was observed in lung cancer cell lines between sensitivity to drugs and to a Fas agonistic mAb, and preincubation of cells with either the Fas-antagonistic mAb CLB-CD95/2 or a FasL-neutralizing mAb did not protect from drug-induced apoptosis. Taken together, these observations strongly argue against a role of the Fas/FasL signaling pathway in drug-induced apoptosis in lung cancer cells. Interestingly, caspase-8 activation was observed upon drug exposure, independently from Fas/FasL signaling.
抗癌药物至少部分通过触发细胞凋亡发挥其细胞毒性作用。我们之前在肺癌细胞中鉴定出化疗诱导的细胞凋亡，并提出p53替代或互补途径在此过程中发挥作用。最近，在某些细胞类型中有人提出Fas/FasL（CD95/Apo1）信号系统在化疗诱导的细胞凋亡中起作用。在本研究中，我们研究了在暴露于四种细胞毒性药物（顺铂、吉西他滨、拓扑替康和紫杉醇）时，Fas/FasL系统在肺癌细胞药物诱导凋亡中的作用。我们评估了六种肺癌细胞系（H460、H322、GLC4、GLC4/ADR、H187和N417）中Fas和FasL的表达以及Fas途径的功能。所有肺癌细胞系在RNA和蛋白质水平均表达Fas和FasL，并且在暴露于Fas激动性单克隆抗体（mAb）CLB-CD95/15后，六个细胞系中的四个可诱导细胞凋亡。然而，药物暴露后，未观察到FasL的显著上调，而野生型p53细胞系H460中的Fas表达增加，而通过直接基因测序证明其他细胞系为突变型p53，Fas表达未增加。此外，在肺癌细胞系中未观察到对药物和Fas激动性mAb的敏感性之间存在相关性，并且用Fas拮抗mAb CLB-CD95/2或FasL中和mAb对细胞进行预孵育并不能保护细胞免受药物诱导的凋亡。综上所述，这些观察结果强烈反对Fas/FasL信号通路在肺癌细胞药物诱导凋亡中起作用。有趣的是，在药物暴露时观察到caspase-8激活，这与Fas/FasL信号无关。
