Direct Inhibition of Elastase Activity by Indole-3-Carbinol Triggers a CD40-TRAF Regulatory Cascade That Disrupts NF-κB Transcriptional Activity in Human Breast Cancer Cells
Direct Inhibition of Elastase Activity by Indole-3-Carbinol Triggers a CD40-TRAF Regulatory Cascade That Disrupts NF-κB Transcriptional Activity in Human Breast Cancer Cells
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DOI：
10.1158/0008-5472.can-09-3349
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发表时间：
2010-06-15
期刊：
影响因子：
11.2
通讯作者：
Firestone, Gary L.
中科院分区：
文献类型：
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作者：
Aronchik, Ida;Bjeldanes, Leonard F.;Firestone, Gary L.
用吲哚-3-甲醇（I3 C）处理高度致瘤性的MDA-MB-231人乳腺癌细胞直接抑制了细胞外弹性蛋白酶依赖的膜相关CD 40（肿瘤坏死因子（TNF）受体超家族成员）的裂解。CD 40信号转导与调节细胞存活、凋亡和增殖以及使乳腺癌细胞对化疗敏感有关，因此是新型乳腺癌治疗的重要潜在靶点。全长未加工的CD 40蛋白的I3 C依赖性蓄积导致通过TNF受体相关因子（TRAF）的CD 40信号传导发生变化，包括NF-κ B转录因子活性的TRAF 1/TRAF 2阳性调节因子和TRAF 3阴性调节因子。由于TRAF 1是NF-κ B B的转录靶基因，I3 C破坏了涉及这些关键细胞存活组分的正反馈环。siRNA抑制弹性蛋白酶表达模拟了I3 C对CD 40蛋白加工和G（1）细胞周期阻滞的抑制作用，而siRNA敲低TRAF 3和NF-κ B抑制剂I κ B则阻止了I3 C诱导的细胞周期阻滞。相反，siRNA敲除PTEN对NF-κ B B活性的I3 C控制没有影响，表明CD 40信号传导在调节该转录因子中的重要性。我们的研究提供了第一个直接的体外证据，即I3 C直接抑制弹性蛋白酶介导的CD 40蛋白水解加工，从而改变下游信号传导，破坏NF-κ B诱导的细胞存活和增殖反应。此外，我们已经建立了一种新的I3 C介导的抗增殖级联反应，具有显著的治疗潜力，用于治疗与高水平弹性蛋白酶及其CD 40膜底物相关的人类癌症。Cancer Res; 70（12）; 4961-71.（C）2010年AACR。
Treatment of highly tumorigenic MDA-MB-231 human breast cancer cells with indole-3-carbinol (I3C) directly inhibited the extracellular elastase-dependent cleavage of membrane-associated CD40, a member of the tumor necrosis factor (TNF) receptor superfamily. CD40 signaling has been implicated in regulating cell survival, apoptosis, and proliferation, as well as in sensitizing breast cancer cells to chemotherapy, and is therefore an important potential target of novel breast cancer treatments. The I3C-dependent accumulation of full-length unprocessed CD40 protein caused a shift in CD40 signaling through TNF receptor-associated factors (TRAF), including the TRAF1/TRAF2 positive regulators and TRAF3 negative regulator of NF-kappa B transcription factor activity. Because TRAF1 is a transcriptional target gene of NF-kappa B, I3C disrupted a positive feedback loop involving these critical cell survival components. siRNA ablation of elastase expression mimicked the I3C inhibition of CD40 protein processing and G(1) cell cycle arrest, whereas siRNA knockdown of TRAF3 and the NF-kappa B inhibitor I kappa B prevented the I3C-induced cell cycle arrest. In contrast, siRNA knockdown of PTEN had no effect on the I3C control of NF-kappa B activity, showing the importance of CD40 signaling in regulating this transcription factor. Our study provides the first direct in vitro evidence that I3C directly inhibits the elastase-mediated proteolytic processing of CD40, which alters downstream signaling to disrupt NF-kappa B-induced cell survival and proliferative responses. Furthermore, we have established a new I3C-mediated antiproliferative cascade that has significant therapeutic potential for treatment of human cancers associated with high levels of elastase and its CD40 membrane substrate. Cancer Res; 70(12); 4961-71. (C)2010 AACR.