Simultaneous modulation of COX-2, p300, Akt, and Apaf-1 signaling by melatonin to inhibit proliferation and induce apoptosis in breast cancer cells
Simultaneous modulation of COX-2, p300, Akt, and Apaf-1 signaling by melatonin to inhibit proliferation and induce apoptosis in breast cancer cells
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褪黑激素同时调节 COX-2、p300、Akt 和 Apaf-1 信号传导，抑制乳腺癌细胞增殖并诱导细胞凋亡
DOI：
10.1111/j.1600-079x.2012.00973.x
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发表时间：
2012-08-01
影响因子：
10.3
通讯作者：
Deng, Wuguo
中科院分区：
文献类型：
--
作者：
Wang, Jingshu;Xiao, Xiangsheng;Deng, Wuguo
褪黑素具有抗炎和抗癌作用，可能是一种抗癌的化学预防和化学治疗剂，但其确切的机制在很大程度上仍未解决。在这项研究中，我们评估了褪黑素对人MDA-MB-361乳腺癌细胞的作用机制。褪黑素在药理学浓度（10-3 m）下显著抑制细胞增殖并诱导细胞凋亡，且呈剂量依赖性。观察到的增殖抑制伴随着褪黑素介导的COX-2、p300和NF-？B信号。褪黑素显著抑制COX-2表达和前列腺素E(2) （PGE2）的产生，抑制p300组蛋白乙酰转移酶活性和p300介导的NF-？B乙酰化，从而阻断NF-？B结合和p300募集到COX-2启动子。COX-2或p300选择性抑制剂预处理可消除褪黑素诱导的细胞增殖抑制，而PGE2处理或COX-2转染可逆转褪黑素的抑制作用。此外，褪黑激素显著抑制PI3K、Akt、PRAS40和GSK-3蛋白的磷酸化，从而使PI3K/Akt信号通路失活。使用PI3K或akt选择性抑制剂或akt特异性siRNA预处理可阻断褪黑素介导的细胞增殖抑制。相反，构成活性Akt的基因传递有效地逆转了褪黑素的抑制作用。此外，褪黑激素诱导Apaf-1表达，触发细胞色素C释放，刺激caspase-3和caspase-9活性和裂解，导致Apaf-1依赖性凋亡通路的激活。用apaf -1特异性siRNA预处理可有效减弱褪黑激素诱导的细胞凋亡。因此，这些结果表明褪黑激素通过同时抑制COX-2/PGE2、p300/NF-？B， PI3K/Akt/信号传导并激活Apaf-1/caspase依赖性凋亡通路。
Melatonin exhibits anti-inflammatory and anticancer effects and could be a chemopreventive and chemotherapeutic agent against cancers, but the precise mechanisms involved remain largely unresolved. In this study, we evaluated the mechanism of action of melatonin in human MDA-MB-361 breast cancer cells. Melatonin at pharmacological concentrations (10-3 m) significantly suppressed cell proliferation and induced apoptosis in a dose-dependent manner. The observed suppression of proliferation was accompanied by the melatonin-mediated inhibition of COX-2, p300, and NF-?B signaling. Melatonin significantly inhibited COX-2 expression and prostaglandin E(2) (PGE2) production, abrogated p300 histone acetyltransferase activity and p300-mediated NF-?B acetylation, thereby blocking NF-?B binding and p300 recruitment to COX-2 promoter. Pretreatment with a COX-2- or p300-selective inhibitor abrogated the melatonin-induced inhibition of cell proliferation, whereas PGE2 treatment or COX-2 transfection reversed the inhibition by melatonin. Moreover, melatonin markedly inhibited phosphorylation of PI3K, Akt, PRAS40, and GSK-3 proteins, thereby inactivating the PI3K/Akt signaling pathway. Pretreatment with a PI3K- or an Akt-selective inhibitor or an Akt-specific siRNA blocked the melatonin-mediated inhibition of cell proliferation. Conversely, gene delivery of a constitutively active Akt effectively reversed the inhibition by melatonin. Furthermore, melatonin induced Apaf-1 expression, triggered cytochrome C release, and stimulated caspase-3 and caspase-9 activities and cleavage, leading to an activation of the Apaf-1-dependent apoptotic pathway. Pretreatment with an Apaf-1-specific siRNA effectively attenuated the melatonin-induced apoptosis. These results therefore indicate that melatonin inhibits cell proliferation and induces apoptosis in MDA-MB-361 breast cancer cells in vitro by simultaneously suppressing the COX-2/PGE2, p300/NF-?B, and PI3K/Akt/signaling and activating the Apaf-1/caspase-dependent apoptotic pathway.