Increased radiation-induced apoptosis of Saos2 cells via inhibition of NFKB: A role for c-Jun N-terminal kinase
Increased radiation-induced apoptosis of Saos2 cells via inhibition of NFKB: A role for c-Jun N-terminal kinase
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DOI：
10.1002/jcb.20607
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发表时间：
2005-12-15
影响因子：
4
通讯作者：
Rosier, RN
中科院分区：
文献类型：
--
作者：
Eliseev, RA;Zuscik, MJ;Rosier, RN
为了阐明NF κ B对放射抗性的可能作用，我们使用了稳定表达NF κ B组成型抑制剂ml κ B（Saos 2-ml κ B）或用空载体稳定转染（Saos 2-EV）的骨肉瘤细胞系Saos 2。电离辐射诱导Saos 2-ml kappa B细胞的“内在”凋亡，但在Saos 2-EV对照细胞中没有，具有完整的NF kappa B活性。我们发现正如预期的那样，在Saos 2-EV对照细胞中照射后，这种NF κ B活性增强。另一方面，在Saos 2-ml kappa B细胞中抑制NF kappa B信号导致促凋亡系统如Bax蛋白和c-Jun N-末端激酶（JNK）/c-Jun/AP 1信号的上调。NF κ B的抑制导致DNA损伤蛋白GADD 45 β（一种已知的JNK抑制剂）的表达降低。随后，c-Jun/AP-1蛋白的JNK激活增加了这些突变体中辐射诱导的细胞凋亡。放射诱导的Saos 2-ml κ B细胞凋亡被JNK特异性抑制剂SP 6001 25以及Bcl-2过表达抑制。此外，在Saos 2-ml κ B细胞中，照射后线粒体细胞色素C的释放增加，caspase-9和-3被激活。反义GADD 45 β抑制剂可显著增强照射后Saos 2-EV细胞的凋亡。我们的研究结果表明，Saos 2骨肉瘤细胞的辐射抗性是由于NF κ B介导的JNK抑制。我们的研究为骨肉瘤放射诱导凋亡的机制提供了新的见解，并可能导致骨肉瘤新的治疗策略的发展。J.细胞。96：1262-1273，2005. (c)2005 Wiley-Liss，Inc.
To elucidate the possible effect of NF kappa B on radioresistance, we used the osteosarcoma cell line Saos2, stably expressing the NF kappa B constitutive inhibitor, ml kappa B (Saos2-ml kappa B) or stably transfected with the empty vector (Saos2-EV). Ionizing radiation induced "intrinsic" apoptosis in Saos2-ml kappa B cells but not in Saos2-EV control cells, with intact NF kappa B activity. We find as expected, that this NF kappa B activity was enhanced following irradiation in the Saos2-EV control cells. On the other hand, inhibition of NF kappa B signaling in Saos2-ml kappa B cells led to the upregulation of the pro-apoptotic systems, such as Bax protein and c-Jun N-terminal Kinase (JNK)/c-Jun/AP1 signaling. Inhibition of NF kappa B resulted in decreased expression of the DNA damage protein GADD45 beta, a known inhibitor of JNK. Subsequently, JNK activation of c-Jun/AP-1 proteins increased radiation-induced apoptosis in these mutants. Radiation-induced apoptosis in Saos2-ml kappa B cells was inhibited by the JNK specific inhibitor SP6001 25 as well as by Bcl-2 over-expression. Furthermore, release of cytochrome-c from mitochondria was increased and caspase-9 and -3 were activated following irradiation in Saos2-ml kappa B cells. Antisense inhibition of GADD45 beta in Saos2-EV cells significantly enhanced apoptosis following irradiation. Our results demonstrate that radioresistance of Saos2 osteosarcoma cells is due to NF kappa B-mediated inhibition of JNK. Our study brings new insight into the mechanisms underlying radiation-induced apoptosis of osteosarcoma, and may lead to development of new therapeutic strategies against osteosarcoma. J. Cell. Biochem. 96:1262-1273, 2005. (c) 2005Wiley-Liss, Inc.