Nitric Oxide-Mediated Inhibition of NFκB Regulates Hyperthermia-Induced Apoptosis
Nitric Oxide-Mediated Inhibition of NFκB Regulates Hyperthermia-Induced Apoptosis
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DOI：
10.1002/jcb.22079
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发表时间：
2009-04-15
影响因子：
4
通讯作者：
Natarajan, Mohan
中科院分区：
文献类型：
--
作者：
Aravindan, Natarajan;Mohan, Sumathy;Natarajan, Mohan
弄清热疗诱导细胞凋亡的上游调控机制，对于了解热疗在肿瘤综合治疗中的作用具有重要意义。因此，我们研究了(I)高温诱导MCF-7乳腺癌细胞凋亡是否通过一氧化氮(NO)信号通路介导，以及(Ii)抑制I-kappa Bα的翻译后修饰和下调核因子-kappaB-DNA结合活性是NO依赖的乳腺癌细胞凋亡的中间步骤。43℃高温处理细胞，DAF-2A荧光强度检测细胞内NO水平，免疫印迹法检测iNOS表达，43℃处理后细胞凋亡率增加，Annexin V表达和克隆形成试验检测细胞存活率，细胞凋亡率增加20%。EMSA分析显示，核因子-kappaB-DNA结合活性呈剂量依赖性抑制。高温对核因子-kappaB的抑制作用持续至48h，L-NAME抑制NO可挽救核因子-kappaB-DNA结合活性，抑制热诱导的细胞凋亡。同样，瞬时转染法过表达核因子kappaB可抑制热诱导的细胞凋亡。这些结果表明，高温暴露下MCF-7细胞的凋亡是由NO介导的对NF-kappa B.J.细胞的抑制所调节的。生物化学。106：999-1009,2009。(C)2009年Wilcy-Liss，Inc.
Ascertaining the upstream regulatory mechanisms of hyperthermia-induced apoptosis is important to understand the role of hyperthermia in combined modality cancer therapy. Accordingly, we investigated whether (i) hyperthermia-induced apoptosis is mediated through the nitric oxide (NO) signaling pathway and (ii) inhibition of post-translational modification Of I kappa B alpha and down regulation of NF kappa B-DNA binding activity is an intermediate step in NO-dependent apoptosis in MCF-7 breast cancer cells. For hyperthermia treatment, the cells were exposed to 43 degrees C. Intracellular NO levels measured by the fluorescent intensity of DAF-2A and iNOS expression by immunobloting revealed an increased level of iNOS dependent NO production after 43 degrees C. Apoptosis measured by Annexin V expression and cell survival by clonogenic assay showed a 20% increase in apoptosis after 43 degrees C treatments. EMSA analysis showed a dose-dependent inhibition of NF kappa B-DNA binding activity. The hyperthermia-mediated inhibition of NF kappa B was persistent even after 48 h. Inhibition of NO by L-NAME rescued the NF kappa B-DNA binding activity and inhibits heat-induced apoptosis. Similarly, over-expression of NF kappa B by transient transfection inhibits heat-induced apoptosis. These results demonstrate that apoptosis upon hyperthermia exposure of MCF-7 cells is regulated by NO-mediated suppression of NF kappa B. J. Cell. Biochem. 106: 999-1009, 2009. (c) 2009 Wilcy-Liss, Inc.