KDM6A promotes imatinib resistance through YY1-mediated transcriptional upregulation of TRKA independently of its demethylase activity in chronic myelogenous leukemia.
KDM6A promotes imatinib resistance through YY1-mediated transcriptional upregulation of TRKA independently of its demethylase activity in chronic myelogenous leukemia.
复制标题
KDM6A 通过 YY1 介导的 TRKA 转录上调促进伊马替尼耐药，独立于慢性粒细胞白血病的去甲基化酶活性
作者：
Zhang C;Shen L;Zhu Y;Xu R;Deng Z;Liu X;Ding Y;Wang C;Shi Y;Bei L;Wei D;Thorne RF;Zhang XD;Yu L;Chen S
原理：尽管使用酪氨酸激酶抑制剂（TKI）治疗慢性粒细胞白血病（CML）具有里程碑意义，但耐药性仍然存在问题。癌症发病机制涉及表观遗传失调，特别是组蛋白赖氨酸脱甲基酶（KDM）与TKI耐药性有关。我们试图识别CML中表达改变的KDM，并确定它们对伊马替尼耐药的贡献。研究方法：生物信息学筛选比较了CML与正常骨髓中KDM的表达，使用shRNA敲除和流式细胞术测量对伊马替尼诱导的K562细胞凋亡的影响。针对KDM 6A CRISPR敲除/shRNA敲低K562细胞进行转录组学分析，沿着使用野生型和突变型脱甲基酶死亡KDM 6A构建体进行基因拯救实验。采用免疫共沉淀、荧光素酶报告基因和ChIP等方法研究KDM 6A依赖性耐药的机制。结果：在CML中上调的5种KDM中，只有KDM 6A缺失使CML细胞对伊马替尼诱导的凋亡敏感。重新引入去甲基酶死亡的KDM 6A以及野生型KDM 6A恢复了伊马替尼耐药性。RNA-seq鉴定了KDM 6A耗竭后NTRK 1基因下调。此外，NTRK 1表达与KDM 6A在一个子集的临床CML样本和KDM 6A敲低在新鲜CML分离减少NTRK 1编码蛋白（TRKA）的表达。从机制上讲，KDM 6A被转录因子YY 1募集到NTRK 1启动子，随后TRKA上调激活下游存活途径，引起伊马替尼耐药。结论：与其作为肿瘤抑制剂的报道作用相反，并且独立于其脱甲基酶功能，KDM 6A促进CML细胞中的伊马替尼耐药性。KDM 6A/YY 1/TRKA轴作为一种新的伊马替尼耐药机制的鉴定代表了一种尚未探索的克服CML TKI耐药的途径。
Rationale: Despite landmark therapy of chronic myelogenous leukemia (CML) with tyrosine kinase inhibitors (TKIs), drug resistance remains problematic. Cancer pathogenesis involves epigenetic dysregulation and in particular, histone lysine demethylases (KDMs) have been implicated in TKI resistance. We sought to identify KDMs with altered expression in CML and define their contribution to imatinib resistance. Methods: Bioinformatics screening compared KDM expression in CML versus normal bone marrow with shRNA knockdown and flow cytometry used to measure effects on imatinib-induced apoptosis in K562 cells. Transcriptomic analyses were performed against KDM6A CRISPR knockout/shRNA knockdown K562 cells along with gene rescue experiments using wildtype and mutant demethylase-dead KDM6A constructs. Co-immunoprecipitation, luciferase reporter and ChIP were employed to elucidate mechanisms of KDM6A-dependent resistance. Results: Amongst five KDMs upregulated in CML, only KDM6A depletion sensitized CML cells to imatinib-induced apoptosis. Re-introduction of demethylase-dead KDM6A as well as wild-type KDM6A restored imatinib resistance. RNA-seq identified NTRK1 gene downregulation after depletion of KDM6A. Moreover, NTRK1 expression positively correlated with KDM6A in a subset of clinical CML samples and KDM6A knockdown in fresh CML isolates decreased NTRK1 encoded protein (TRKA) expression. Mechanistically, KDM6A was recruited to the NTRK1 promoter by the transcription factor YY1 with subsequent TRKA upregulation activating down-stream survival pathways to invoke imatinib resistance. Conclusion: Contrary to its reported role as a tumor suppressor and independent of its demethylase function, KDM6A promotes imatinib-resistance in CML cells. The identification of the KDM6A/YY1/TRKA axis as a novel imatinib-resistance mechanism represents an unexplored avenue to overcome TKI resistance in CML.