Curcumin prevents As(3+)-induced carcinogenesis through regulation of GSK3β/Nrf2.
Curcumin prevents As(3+)-induced carcinogenesis through regulation of GSK3β/Nrf2.
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DOI：
10.1186/s13020-021-00527-x
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发表时间：
2021-11-10
期刊：
影响因子：
4.9
通讯作者：
Dai XY
中科院分区：
文献类型：
--
作者：
Dang YY;Luo H;Li YM;Zhou Y;Luo X;Lin SM;Liu SP;Lee SM;Li CW;Dai XY
砷(As3+)是一种与环境和职业密切相关的致癌物质。其作用机制和预防方法尚待研究。以往的研究表明，ROS参与了As3+诱导的细胞转化，被认为是As3+致癌的第一阶段。核因子-E2P45相关因子-2(Nrf2)信号通路调节细胞的抗氧化反应，Nrf2的激活最近被证明可以限制As3+暴露后的氧化损伤。在本研究中，分子对接被用于虚拟筛选天然抗氧化剂化学数据库并识别与Keap1(PDB代码4L7B)配体结合位点相互作用的分子。细胞检测和分子对接结果表明，姜黄素对Keap1-4L7B具有最好的抑制活性。免疫共沉淀(Co-IP)结果表明，姜黄素是一种有效的Keap1Kelch结构域依赖的Nrf2激活剂，通过阻碍Nrf2的泛素化来稳定Nrf2。姜黄素增加Nrf2及其靶基因的激活，可显著降低As3+产生的ROS。此外，姜黄素通过形成p62/LC-3复合体诱导自噬，并通过促进转录因子EB(TFEB)和溶酶体相关膜蛋白1(LAMP1)的表达来增加自噬通量，从而诱导As3+处理的BEAS-2B细胞自噬。Nrf2基因的敲除可消除姜黄素诱导的自噬并下调ROS。进一步的研究表明，抑制自噬小体和溶酶小体与巴菲霉素A1(BafA1)的融合可以阻断姜黄素，并阻止As3+诱导的细胞转化。这些结果表明，姜黄素通过激活BEAS-2B细胞中的Nrf2信号通路诱导自噬，从而阻止As3+诱导的细胞转化。然而，KEAP-1的过表达表明As3+转化的BEAS-2B细胞(AST)中Nrf2的结构性高水平是KEAP-1不依赖的调节。Nrf2在AST中的过表达表明，姜黄素通过下调Nrf2的表达，增加ROS水平，诱导细胞凋亡。进一步研究表明，姜黄素通过激活GSK-3β，抑制PI3K/AKT的激活，从而降低天冬氨酸转氨酶中NRF2的水平。Co-IP分析结果表明，姜黄素促进NRF2与GSK-3、β/β-TrCP轴和泛素的相互作用。此外，抑制GSK-3β逆转了姜黄素处理的AST中NRF2的表达，表明NRF2的减少是由于激活了GSK-3β/β-TrCP泛素化途径。此外，体外和体内实验结果表明，姜黄素通过激活β/β-TrCP泛素化途径，降低NRF2的表达，从而诱导细胞凋亡，并具有抗血管生成和抗肿瘤的作用。综上所述，在第一阶段，姜黄素激活Nrf2，降低ROS，并诱导正常细胞自噬，以防止As3+诱导的细胞转化。在第二阶段，姜黄素通过抑制Nrf2在AST中的结构性表达，促进ROS和细胞凋亡，抑制血管生成，从而阻止肿瘤的发生。我们的结果表明，抗氧化剂天然化合物，如姜黄素，可以被评估为治疗As3+诱导的致癌的补充疗法的潜在候选者。
Arsenic (As3+) is a carcinogen with considerable environmental and occupational relevancy. Its mechanism of action and methods of prevention remain to be investigated. Previous studies have demonstrated that ROS is responsible for As3+-induced cell transformation, which is considered as the first stage of As3+ carcinogenesis. The NF-E2 p45-related factor-2 (Nrf2) signaling pathway regulates the cellular antioxidant response, and activation of Nrf2 has recently been shown to limit oxidative damage following exposure to As3+ In this study, molecular docking was used to virtually screen natural antioxidant chemical databases and identify molecules that interact with the ligand-binding site of Keap1 (PDB code 4L7B). The cell-based assays and molecular docking findings revealed that curcumin has the best inhibitory activity against Keap1-4L7B. Co-immunoprecipitation (Co-IP) results indicated that curcumin is a potent Keap1 Kelch domain-dependent Nrf2 activator that stabilizes Nrf2 by hindering its ubiquitination. The increased activation of Nrf2 and its target antioxidant genes by curcumin could significantly decrease As3+-generated ROS. Moreover, curcumin induced autophagy in As3+-treated BEAS-2B via inducing autophagy by the formation of a p62/LC-3 complex and increasing autophagic flux by promoting transcription factor EB (TFEB) and lysosome-associated membrane protein 1 (LAMP1) expression. Knockdown of Nrf2 abolished curcumin-induced autophagy and downregulated ROS. Further studies showed that inhibition of autophagosome and lysosome fusion with bafilomycin a1 (BafA1) could block curcumin and prevented As3+-induced cell transformation. These results demonstrated that curcumin prevents As3+-induced cell transformation by inducing autophagy via the activation of the Nrf2 signaling pathway in BEAS-2B cells. However, overexpression of Keap-1 showed a constitutively high level of Nrf2 in As3+-transformed BEAS-2B cells (AsT) is Keap1-independent regulation. Overexpression of Nrf2 in AsT demonstrated that curcumin increased ROS levels and induced cell apoptosis via the downregulation of Nrf2. Further studies showed that curcumin decreased the Nrf2 level in AsT by activating GSK-3β to inhibit the activation of PI3K/AKT. Co-IP assay results showed that curcumin promoted the interaction of Nrf2 with the GSK-3β/β-TrCP axis and ubiquitin. Moreover, the inhibition of GSK-3β reversed Nrf2 expression in curcumin-treated AsT, indicating that the decrease in Nrf2 is due to activation of the GSK-3β/β-TrCP ubiquitination pathway. Furthermore, in vitro and in vivo results showed that curcumin induced cell apoptosis, and had anti-angiogenesis and anti-tumorigenesis effects as a result of activating the GSK-3β/β-TrCP ubiquitination pathway and subsequent decrease in Nrf2. Taken together, in the first stage, curcumin activated Nrf2, decreased ROS, and induced autophagy in normal cells to prevent As3+-induced cell transformation. In the second stage, curcumin promoted ROS and apoptosis and inhibited angiogenesis via inhibition of constitutive expression of Nrf2 in AsT to prevent tumorigenesis. Our results suggest that antioxidant natural compounds such as curcumin can be evaluated as potential candidates for complementary therapies in the treatment of As3+-induced carcinogenesis.
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影响因子：
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作者：
González-Reyes S;Guzmán-Beltrán S;Medina-Campos ON;Pedraza-Chaverri J
通讯作者：
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影响因子：
7.4
作者：
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通讯作者：
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