EZH2通过表观沉默免疫细胞活性相关靶基因参与肿瘤微环境(TME)调控是EZH2致癌新机制，浸润性iTregs富集是HCC患者TME的重要表型特征。预实验进行了HCC小鼠TME中Tregs的转录组分析，发现:Ezh2抑制剂上调Bambi；显著抑制Tgf-β通路；并诱导多种免疫调节因子表达变化。由此提出科学假设：Ezh2通过Bambi/Tgf-β通路调控Tregs分化影响HCC的TME。我们基于可诱导的Foxp3+Tregs细胞特异性Ezh2基因敲除小鼠及HCC模型，验证Tregs敲除Ezh2对Tregs的细胞及免疫学表型、TME改变及肿瘤发生发展的影响；并通过表达谱、H3K27me3修饰谱分析，筛选并验证关键信号通路(如Tgf-β)和靶基因，揭示Ezh2调控Tregs的分子机制。此项目将阐明Ezh2依赖的iTregs细胞分化和功能的调控途径，为以Ezh2为靶点的HCC免疫治疗提供理论依据。

The occurrence, development and prognosis of hepatocellular carcinoma (HCC) is closely correlated with the microenvironment of HCC. It has been revealed that the landscape of infiltrating of T cells in tumor microenvironment of HCC patients is abnormal, that is the infiltrated Tregs and exhausted CD8+ T cells are preferentially enriched and potentially clonally expanded; EZH2, the H3K27 methyltransferase, is overexpression in multiple cancers, and has been treated as the candidate drug target for clinical carcinoma therapy. Recently, EZH2 was verified to be involved in regulation of differentiation, plasticity and immune activation of CD4 T cell. Especially, in Tregs, which combined with FOXP3 and play a key role in maintaining the activated state of Tregs. Furthermore, in our study, treatment with Ezh2 inhibitor (DZNep) contribute to inhibition of Tgf-β1 signaling pathway, the primary pathway for promoting differentiation of Tregs, through upregulation of its inhibitor Bambi and wide downregulation of its effectors; Moreover, multiple interleukins and chemokines or their receptors involved in differentiation, activation and migration of T cells were also regulated by EZH2 inhibitor. These results indicate that EZH2 may be involved in HCC immunosuppression through regulating the function of Tregs. Therefore, in this subject, we construct the conditional Ezh2-deleted transgenic mice induced by tamoxifen in Tregs, and further induce the hepatocellular carcinoma in these mice using in situ graft with HCC cells. Then the effect of EZH2-deletion in Tregs on immune microenvironment of HCC will be verified by analyzing the infiltration, subpopulation and activation of T cells. In addition, the mechanism of EZH2-mediated regulation on immunosuppression function of Tregs will be revealed by screening and verifying the key target genes and pathways through analysis of the transcriptome and epigenome of EZH2-deleted and control Tregs. This subject will provide a potential way for HCC immunity therapy.