Blocking of JB6 Cell Transformation by Tanshinone IIA: Epigenetic Reactivation of Nrf2 Antioxidative Stress Pathway
Blocking of JB6 Cell Transformation by Tanshinone IIA: Epigenetic Reactivation of Nrf2 Antioxidative Stress Pathway
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DOI：
10.1208/s12248-014-9666-8
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发表时间：
2014-11-01
期刊：
影响因子：
4.5
通讯作者：
Kong, Ah-Ng Tony
中科院分区：
文献类型：
--
作者：
Wang, Ling;Zhang, Chengyue;Kong, Ah-Ng Tony
越来越多的天然产物被发现具有抗癌作用。核因子红细胞-2相关因子-2 （Nrf2）是抗氧化应激反应的主要调控因子，我们之前的研究发现Nrf2基因的表观遗传修饰可能是一个关键的机制。丹参是一种在亚洲国家广泛使用的中草药，已被证明具有抗癌和抗氧化作用。丹参酮IIA （Tanshinone IIA， TIIA）是丹参中的一种活性成分，据报道可激活Nrf2通路。本研究的目的是研究TIIA对小鼠皮肤表皮JB6细胞Nrf2的表观遗传调控及其对细胞转化的功能影响。TIIA可诱导抗氧化反应元件-荧光素酶，上调Nrf2和Nrf2下游靶基因HO-1和NQO-1的mRNA和蛋白水平。TIIA使JB6细胞的集落形成减少约80%。TIIA降低DNMT1、DNMT3a、DNMT3b和HDAC3蛋白水平，抑制HDACs酶活性。亚硫酸氢盐基因组测序表明，TIIA使Nrf2基因启动子区域的前5个CpGs去甲基化。染色质免疫沉淀实验显示，TIIA处理增加了Nrf2转录起始位点RNA聚合酶II的募集，但对Nrf2启动子Ac-H3的富集影响有限。综上所述，我们的研究结果表明，TIIA激活Nrf2信号通路并诱导Nrf2 CpGs的表观遗传去甲基化。TIIA对Nrf2信号通路的表观遗传再激活可能有助于抑制JB6细胞转化和抗癌作用。
Increasing numbers of natural products have been found to possess anticancer effects. Nuclear factor erythroid-2-related factor-2 (Nrf2) is a master regulator of the antioxidative stress response, and our previous studies found that epigenetic modification of the Nrf2 gene appears to be a critical mechanism. Salvia miltiorrhiza, a Chinese herbal medicine widely used in Asian countries, has been shown to possess anticancer and antioxidant effects. Tanshinone IIA (TIIA), an active component in S. miltiorrhiza, has been reported to activate Nrf2 pathway. The objective of this study was to investigate the epigenetic regulation of Nrf2 by TIIA in mouse skin epidermal JB6 cells and the functional consequences for cell transformation. TIIA was found to induce antioxidant response element-luciferase and upregulate the mRNA and protein levels of Nrf2 and Nrf2 downstream target genes HO-1 and NQO-1. TIIA decreased the colony formation of JB6 cells by approximately 80%. TIIA decreased the protein levels of DNMT1, DNMT3a, DNMT3b, and HDAC3 and inhibited the enzymatic activity of HDACs. Bisulfite genomic sequencing indicated that TIIA demethylated the first five CpGs in the promoter region of the Nrf2 gene. Chromatin immunoprecipitation assays showed that TIIA treatment increased the recruitment of RNA polymerase II at Nrf2 transcription start site but had limited effects on enrichment of Ac-H3 in Nrf2 promoter. Taken together, our results show that TIIA activates the Nrf2 signaling pathway and induces epigenetic demethylation of the CpGs of Nrf2. The epigenetic reactivation of the Nrf2 signaling pathway by TIIA could potentially contribute to the attenuation of JB6 cellular transformation and anticancer effects.