This study aimed to explore the interaction between the tumor-associated macrophage (TAM) and enhancer of zeste homolog 2 (EZH2) in tumor microenvironment of lung cancer are obscure. M2 type of TAM was induced by interleukin-4 (IL-4) and interleukin-13 (IL-13) in RAW264.7 cells. Subsequently, the co-culture system of the M2 RAW264.7 treating LLC-1 cells were constructed to evaluate the cell proliferation, migration and invasion abilities. On top of that, the M2 RAW264.7 was injected into the LLC-1 cells-bearing mice. Tumor growth and the number of metastatic nodes were observed. Moreover, DNA methylation, EZH2 expression, target genes of EZH2 and the M2 type TAM-related markers were detected in vivo and in vitro. Further experiments of EZH2 function in lung cancer were carried out by the addition of EZH2 inhibitor (GSK126) and si-EZH2. M2 type of TAM was induced with IL-4 and IL-13 with increased expression of CD206, CD68, CD163 and Arg1. Following co-culture with M2 type TAM, the proliferative, invasive, migrative abilities, tumor growth and metastasis, and the DNA methylation, EZH2 level were strengthened whereas the target genes of EZH2, including p21, CDKN2A, CDKN2B were reduced in LLC-1 cells and LLC-1 cell-bearing mice. Of note, GSK126 and si-EZH2 offset the M2 type TAM's effects, and inhibited the LLC-1 cell metastasis, DNA methylation and tumor growth. M2 type TAM promoted DNA methylation in LLC-1 cells and LLC-1 cell-bearing mice, which is related to the intensified EZH2.

中文翻译：

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M2肿瘤相关巨噬细胞通过强化EZH2促进肺癌转移中的DNA甲基化。

本研究旨在探讨肺癌肿瘤微环境中肿瘤相关巨噬细胞（TAM）与zeste同源物增强子2（EZH2）之间的相互作用。M2型TAM是由白细胞介素4（IL-4）和白细胞介素13（IL-13）在RAW264.7细胞中诱导的。随后，构建了M2 RAW264.7处理LLC-1细胞的共培养体系，以评估细胞增殖、迁移和侵袭能力。最重要的是，将 M2 RAW264.7 注射到携带 LLC-1 细胞的小鼠体内。观察肿瘤生长和转移淋巴结的数量。此外，在体内和体外检测DNA甲基化、EZH2表达、EZH2靶基因和M2型TAM相关标记。通过添加EZH2抑制剂（GSK126）和si-EZH2，进一步进行了EZH2在肺癌中的功能实验。IL-4 和 IL-13 诱导 M2 型 TAM，CD206、CD68、CD163 和 Arg1 表达增加。与M2型TAM共培养后，LLC-1的增殖、侵袭、迁移能力、肿瘤生长和转移能力以及DNA甲基化、EZH2水平增强，而EZH2的靶基因，包括p21、CDKN2A、CDKN2B降低细胞和携带 LLC-1 细胞的小鼠。值得注意的是，GSK126和si-EZH2抵消了M2型TAM的作用，并抑制了LLC-1细胞的转移、DNA甲基化和肿瘤生长。M2型TAM促进LLC-1细胞和携带LLC-1细胞的小鼠的DNA甲基化，这与EZH2的强化有关。