NUT癌（NC）是一种由BRD4-NUT融合致癌蛋白驱动的侵袭性癌症，该蛋白激活染色质来促进生长相关基因的表达。BET组蛋白结构域抑制剂（BETi）阻碍了BRD4-NUT激活基因的能力，因此是一种有前景的治疗方法，但其单独用药效果有限。基因抑制在NC中的作用尚不清楚。在本研究中，我们证明了通过建立抑制性染色质来沉默基因的EZH2在NC中是必需的。使用临床化合物tazemetostat（taz）抑制EZH2能够有效阻断NC细胞的生长。表观遗传和转录组学分析表明，taz能够扭转EZH2特异性的H3K27me3沉默标记，并恢复多个抑癌基因的表达，而对关键的致癌BRD4-NUT调控的基因没有影响。在CRISPR-Cas9筛选中，CDKN2A被确定为所有taz解抑基因中唯一的能够对taz表现出耐药性的基因。EZH2抑制和BET抑制的联用通过下调细胞增殖相关基因，使细胞增殖明显停止并促进分化，效果比单独使用任何一种抑制剂都更加显著。在临床前模型中，联合使用taz和BETi能够剂量协同地阻断NC移植小鼠的生长，并延长其生存期，在一个队列中所有的小鼠都被治愈。EZH2作为NC的一个依赖因子的识别证实了NC肿瘤细胞对功能相反但高度互补的染色质调控途径的表观遗传失调的依赖性，以维持NC的生长。特别是，EZH2通过抑制CDKN2A的表达为将EZH2i与BETi联合应用于NC的临床治疗提供了机制合理性。

NUT carcinoma (NC) is an aggressive carcinoma driven by the BRD4-NUT fusion oncoprotein, which activates chromatin to promote expression of pro-growth genes. BET bromodomain inhibitors (BETi) impede BRD4-NUT's ability to activate genes and are thus a promising treatment but limited as monotherapy. The role of gene repression in NC is unknown. Here, we demonstrate that EZH2, which silences genes through establishment of repressive chromatin, is a dependency in NC. Inhibition of EZH2 with the clinical compound tazemetostat (taz) potently blocked growth of NC cells. Epigenetic and transcriptomic analysis revealed that taz reversed the EZH2-specific H3K27me3 silencing mark, and restored expression of multiple tumor suppressor genes while having no effect on key oncogenic BRD4- NUT-regulated genes. CDKN2A was identified as the only gene amongst all taz-derepressed genes to confer resistance to taz in a CRISPR-Cas9 screen. Combined EZH2 inhibition and BET inhibition synergized to downregulate cell proliferation genes resulting in more pronounced growth arrest and differentiation than either inhibitor alone. In pre-clinical models, combined taz and BETi synergistically blocked growth and prolonged survival of NC-xenografted mice, with all mice cured in one cohort.Identification of EZH2 as a dependency in NC substantiates the reliance of NC tumor cells on epigenetic dysregulation of functionally opposite, yet highly complementary chromatin regulatory pathways to maintain NC growth. In particular, repression of CDKN2A expression by EZH2 provides a mechanistic rationale for combining EZH2i with BETi for the clinical treatment of NC.