Apoptosis in UV-C light irradiated p53 wild-type, apaf-1 and p53 knockout mouse embryonic fibroblasts: Interplay of receptor and mitochondrial pathway
Apoptosis in UV-C light irradiated p53 wild-type, apaf-1 and p53 knockout mouse embryonic fibroblasts: Interplay of receptor and mitochondrial pathway
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UV-C 光照射 p53 野生型、apaf-1 和 p53 敲除小鼠胚胎成纤维细胞中的细胞凋亡：受体和线粒体途径的相互作用
DOI：
10.1007/s10495-005-1392-3
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发表时间：
2005
期刊：
影响因子：
7.2
通讯作者：
B. Kaina
中科院分区：
文献类型：
--
作者：
M. Tomicic;M. Christmann;B. Kaina
小鼠胚胎成纤维细胞（MEFs）缺乏转录因子p53是超敏感的UV-C光。它们还显示从UV-C诱导的复制阻断的恢复减少，并且不能修复UV-C光产物。在这项研究中，我们利用野生型（wt），Apaf-1缺陷（apaf-1−/−）和p53缺陷（p53−/−）MEFs，以阐明未修复的UV-C损伤在凋亡信号传导中的作用。与WST测定确定的细胞敏感性相对应，p53−/−细胞在UV-C照射后显示出最高水平的凋亡，而wt细胞显示出中度凋亡。Apaf 1 −/−细胞的耐药性最强。野生型细胞凋亡通过线粒体和受体介导的途径进行，如Bcl-2下降，fasR诱导和caspase-3，8，9激活所示。在apaf-1−/−（p53+/+）细胞中，Bcl-2下游的线粒体途径被阻断，表明在这种情况下，细胞凋亡是通过诱导fasR和caspase-3，8激活介导的。在p53缺陷细胞中，未修复的UV-C诱导的DNA损伤触发了fas配体（fasL）mRNA的持续上调，这在wt和apaf-1−/−细胞中没有观察到。因此，在p53−/− MEFs中，受体/配体触发通路似乎占主导地位。这通过DN-FADD转染后细胞凋亡的显著减少来证实。与野生型和apaf-1−/−细胞相反，p53缺陷型MEFs没有表现出Fas受体的诱导作用，也没有表现出Bcl-2的下降。尽管如此，与wt和apaf-1−/−细胞相比，caspase-8和-3的活化作用更强。数据表明，UV-C光会激活MEF中的Fas（CD 95、Apo-1）受体和线粒体损伤途径。然而，在p53−/−细胞中，高水平的未修复的DNA损伤迫使fasL上调信号，导致UV-C诱导的细胞凋亡增强。
Mouse embryonic fibroblasts (MEFs) deficient for the transcription factor p53 are hypersensitive to UV-C light. They also show a reduced recovery from UV-C induced replication blockage and are unable to repair UV-C photoproducts. In this study, we utilized wild-type (wt), Apaf-1 deficient (apaf-1−/−) and p53 deficient (p53−/−) MEFs in order to elucidate the role of non-repaired UV-C lesions in apoptotic signalling. Corresponding with the cellular sensitivity determined by the WST assay, p53−/− cells displayed the highest level of apoptosis, whereas wt cells showed moderate apoptosis after UV-C irradiation. Apaf1−/− cells were most resistant. In wt cells apoptosis was executed both via the mitochondrial and the receptor-mediated pathway, as shown by Bcl-2 decline, induction of fasRand activation of caspases-3,8,9. In apaf-1−/− (p53+/+) cells, the mitochondrial pathway was blocked downstream of Bcl-2, indicating that in this case apoptosis was mediated via the induction of fasR and caspase-3,8 activation. In p53 deficient cells, non-repaired UV-C induced DNA lesions triggered sustained up-regulation of fas ligand (fasL) mRNA, which was not seen in wt and apaf-1−/− cells. Therefore, in p53−/− MEFs, the receptor/ligand triggered pathway appeared to be dominant. This was confirmed by significant reduction of apoptosis after DN-FADD transfection. As opposed to wt and apaf-1−/− cells, p53 deficient MEFs showed no induction of Fas receptor and no Bcl-2 decline. Nevertheless, the resulting caspase-8 and -3 activation was stronger compared to wt and apaf-1−/− cells. The data indicate that UV-C light activates in MEFs both the Fas (CD95, Apo-1) receptor and the mitochondrial damage pathways. In p53−/− cells, however, the high level of non-repaired DNA damage forces signalling by fasL upregulation, leading to enhanced UV-C-induced apoptosis.
DOI：
10.1073/pnas.96.24.13777
发表时间：
1999-11-23
影响因子：
11.1
作者：
Chehab, NH;Malikzay, A;Halazonetis, TD
通讯作者：
Halazonetis, TD
DOI：
10.1073/pnas.96.26.14973
发表时间：
1999-12-21
影响因子：
11.1
作者：
Khosravi, R;Maya, R;Shkedy, D
通讯作者：
Shkedy, D