Division of Anti-Tumor Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, PR China.
Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, PR China.
Cell Death Dis. 2022 Aug 29;13(8):748. doi: 10.1038/s41419-022-05169-x.
Tumor associated macrophages (TAMs) play an important role in tumorigenesis, development and anti-cancer drug therapy. However, very few epigenetic compounds have been elucidated to affect tumor growth by educating TAMs in the tumor microenvironment (TME). Herein, we identified that EZH2 performs a crucial role in the regulation of TAMs infiltration and protumoral polarization by interacting with human breast cancer (BC) cells. We showed that EZH2 inhibitors-treated BC cells induced M2 macrophage polarization in vitro and in vivo, while EZH2 knockdown exhibited the opposite effect. Mechanistically, inhibition of EZH2 histone methyltransferase alone by EZH2 inhibitors in breast cancer cells could reduce the enrichment of H3K27me3 on CCL2 gene promoter, elevate CCL2 transcription and secretion, contributing to the induction of M2 macrophage polarization and recruitment in TME, which reveal a potential explanation behind the frustrating results of EZH2 inhibitors against breast cancer. On the contrary, EZH2 depletion led to DNA demethylation and subsequent upregulation of miR-124-3p level, which inhibited its target CCL2 expression in the tumor cells, causing arrest of TAMs M2 polarization. Taken together, these data suggested that EZH2 can exert opposite regulatory effects on TAMs polarization through its enzymatic or non-enzymatic activities. Our results also imply that the effect of antitumor drugs on TAMs may affect its therapeutic efficacy, and the combined application with TAMs modifiers should be warranted to achieve great clinical success.
肿瘤相关巨噬细胞(TAMs)在肿瘤发生、发展和抗癌药物治疗中发挥着重要作用。然而,很少有表观遗传化合物被阐明可以通过在肿瘤微环境(TME)中教育 TAMs 来影响肿瘤生长。在这里,我们发现 EZH2 通过与人类乳腺癌(BC)细胞相互作用,在调节 TAMs 浸润和促肿瘤极化方面起着至关重要的作用。我们表明,EZH2 抑制剂处理的 BC 细胞在体外和体内诱导 M2 巨噬细胞极化,而 EZH2 敲低则表现出相反的效果。在机制上,EZH2 抑制剂单独抑制 EZH2 组蛋白甲基转移酶可减少 H3K27me3 在 CCL2 基因启动子上的富集,增加 CCL2 的转录和分泌,有助于诱导 M2 巨噬细胞在 TME 中的极化和募集,这揭示了 EZH2 抑制剂对乳腺癌治疗效果令人沮丧的潜在原因。相反,EZH2 缺失导致 DNA 去甲基化,随后 miR-124-3p 水平上调,抑制了肿瘤细胞中其靶基因 CCL2 的表达,导致 TAMs M2 极化停滞。总之,这些数据表明,EZH2 可以通过其酶或非酶活性对 TAMs 极化产生相反的调节作用。我们的研究结果还表明,抗肿瘤药物对 TAMs 的作用可能会影响其治疗效果,应与 TAMs 调节剂联合应用,以实现巨大的临床成功。