METHODS: Network pharmacology was adopted for analyzing the targets and signaling pathways related to the M2 polarization of EBC-macrophages, small molecular-protein docking was employed to analyze the possibility of EBC bonding to related protein, and molecular dynamics was introduced to analyze the binding energy between EBC and HDAC2. The M2 polarization of RAW264.7 macrophages was triggered in vitro by IL-4. After EBC intervention, the expressions of M1/M2 polarization-related cytokines were detected, and the mechanism of EBC action was explored in HDAC2-knockout RAW264.7 macrophages. A tumor-bearing mouse model was established in vitro to find the impact of EBC on tumor-associated M2 macrophages.
RESULTS: As revealed by the network pharmacology, molecular docking and molecular dynamics analyses, EBC was associated with 51 proteins, including HDAC2, NF-κB and HDAC4. Molecular docking and dynamics analyses suggested that HDAC2 was the main target of EBC. In vitro experiments discovered that EBC could hinder the M2 polarization of RAW264.7 macrophages, which exerted insignificant effect on the M1-associated cytokines, but could lower the levels of M2-associated cytokines. After knocking out HDAC2, EBC could not further inhibit the M2 polarization of macrophages. At the mouse level, EBC could hinder the tumor growth and the tissue levels of M2 macrophages, whose effect was associated with HDAC2.
CONCLUSIONS: Our study combining multiple methods finds that EBC inhibits the HDAC2-mediated M2 polarization of macrophages, thereby playing an anti-tumor role.
方法:采用网络药理学分析EBC-巨噬细胞M2极化相关的靶点和信号通路,利用小分子-蛋白对接分析EBC与相关蛋白结合的可能性,引入分子动力学分析EBC与HDAC2的结合能。RAW264.7巨噬细胞的M2极化在体外由IL-4触发。EBC干预后,检测M1/M2极化相关细胞因子的表达,在HDAC2敲除的RAW264.7巨噬细胞中探索了EBC的作用机制。体外建立荷瘤小鼠模型以发现EBC对肿瘤相关M2巨噬细胞的影响。
结果:正如网络药理学所揭示的那样,分子对接和分子动力学分析,EBC与51种蛋白质相关,包括HDAC2、NF-κB和HDAC4。分子对接和动力学分析表明HDAC2是EBC的主要靶标。体外实验发现EBC能阻碍RAW264.7巨噬细胞的M2极化,对M1相关细胞因子的影响不明显,但可以降低M2相关细胞因子的水平。敲除HDAC2后,EBC不能进一步抑制巨噬细胞的M2极化。在鼠标级别,EBC可以阻碍肿瘤生长和M2巨噬细胞的组织水平,其作用与HDAC2有关。
结论:我们结合多种方法的研究发现,EBC抑制HDAC2介导的巨噬细胞M2极化,从而发挥抗肿瘤作用。