Active roles for inhibitory kappaB kinases alpha and beta in nuclear factor-kappaB-mediated chemoresistance to doxorubicin.
Active roles for inhibitory kappaB kinases alpha and beta in nuclear factor-kappaB-mediated chemoresistance to doxorubicin.
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DOI：
10.1158/1535-7163.mct-08-0321
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发表时间：
2008-07
影响因子：
5.7
通讯作者：
Kim, Hong J.
中科院分区：
文献类型：
--
作者：
Bednarski, Brian K.;Ding, Xiaoyu;Coombe, Kavita;Baldwin, Albert S.;Kim, Hong J.
化疗药物已被证明诱导转录因子NF-κB和随后的耐药性纤维肉瘤和其他癌症。NF-κ B介导的化疗耐药的机制尚不清楚，先前的报道表明阿霉素诱导这种反应不依赖于抑制性κB激酶（IKK）。其他研究表明需要IKKβ，而不是IKKα。用阿霉素处理缺乏IKKα、IKKβ或两种亚基（DKO）的小鼠胚胎成纤维细胞（MEF）。IKKα或IKKβ或两种激酶的缺失导致多柔比星诱导NF-κB DNA结合活性受损。为了提供有效的临床相关性，用IKKα或IKKβ特异性小干扰RNA（siRNA）转染HT 1080人纤维肉瘤细胞，然后用阿霉素处理。IKKα的敲低严重损害了阿霉素启动NF-κB DNA结合活性的能力。然而，IKKα或IKKβ的降低导致p65对阿霉素的磷酸化反应降低。与单独使用多柔比星相比，通过敲低任一催化亚基抑制多柔比星诱导的NF-κB活化，导致裂解的caspase 3和裂解的PARP增加，细胞凋亡增加。本研究的结果验证了目前旨在抑制NF-κB以改善临床治疗的方法。此外，我们证明IKKα在NF-κ B介导的阿霉素化疗耐药性中起关键作用，并可能作为改善化疗反应的联合策略的潜在靶点。
Chemotherapy agents have been shown to induce the transcription factor NF-κB and subsequent chemoresistance in fibrosarcomas and other cancers. The mechanism of NF-κB-mediated chemoresistance remains unclear, with a previous report suggesting that doxorubicin induces this response independent of the inhibitory κB kinases (IKKs). Other studies have indicated that IKKβ, but not IKKα, is required. Mouse embryo fibroblasts (MEF) devoid of IKKα, IKKβ, or both subunits (DKO) were treated with doxorubicin. The absence of either IKKα or IKKβ or both kinases resulted in impaired induction of NF-κB DNA-binding activity in response to doxorubicin. To provide a valid clinical correlate, HT1080 human fibrosarcoma cells were transfected with small interference RNAs (siRNAs) specific for IKKα or IKKβ and then subsequently treated with doxorubicin. Knockdown of IKKα severely impaired the ability of doxorubicin to initiate NF-κB DNA-binding activity. However, a decrease in either IKKα or IKKβ resulted in decreased phosphorylation of p65 in response to doxorubicin. The inhibition of doxorubicin-induced NF-κB activation by the knockdown of either catalytic subunit resulted in increased cleaved caspase 3 and cleaved PARP, and increased apoptosis when compared to doxorubicin alone. The results of this study validate current approaches aimed at NF-κB inhibition to improve clinical therapies. Moreover, we demonstrate that IKKα plays a critical role in NF-κB-mediated chemoresistance in response to doxorubicin and may serve as a potential target in combinational strategies to improve chemotherapeutic response.