Inhibition of Histone H3K27 Demethylases Inactivates Brachyury (TBXT) and Promotes Chordoma Cell Death
Inhibition of Histone H3K27 Demethylases Inactivates Brachyury (TBXT) and Promotes Chordoma Cell Death
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DOI：
10.1158/0008-5472.can-20-1387
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发表时间：
2020-10-15
期刊：
影响因子：
11.2
通讯作者：
Flanagan, Adrienne M.
中科院分区：
文献类型：
--
作者：
Cottone, Lucia;Cribbs, Adam P.;Flanagan, Adrienne M.
转录因子Brachyury（TBXT）的表达通常限于胚胎，其沉默受表观遗传学调控。TBXT促进常见癌的一个亚组中的间质转化，并且在脊索瘤（一种显示脊索分化的罕见癌症）中，TBXT充当假定的癌基因。我们假设TBXT的表达是通过表观遗传抑制促进脉络膜细胞死亡来控制的。对五种人类脊索瘤细胞系的筛选表明，组蛋白3赖氨酸27脱甲基酶KDM 6A（UTX）和KDM 6 B（JMJD 3）的药理学抑制会导致细胞死亡。这种效应通过使用CRISPR/Cas9的KDM 6A/B的双重遗传失活来表型模仿。用新化合物KDOBA 67抑制KDM 6 A/B导致抑制性H3 K27 me 3标记的全基因组增加，同时活性H3 K27 ac、H3 K9 ac和H3 K4 me 3标记减少。TBXT是KDM 6A/B靶基因，KDOBA 67处理后TBXT的染色质变化与所有测试模型（包括原代患者来源的培养物）中TBXT蛋白水平的降低相关。在所有测试的模型中，KDOBA 67治疗下调了对脉络膜存活至关重要的转录因子网络的表达，并上调了由ATF 4驱动的应激和促凋亡反应主导的途径。阻断AFT 4应激反应并不能阻止TBXT的抑制和细胞死亡的诱导，但TBXT的异位过表达增加了活力，因此暗示TBXT是H3 K27去甲基化酶抑制剂在脉络膜中的潜在治疗靶点。我们的工作突出了如何在胎儿发育的正常过程中的知识可以提供洞察肿瘤发生和确定新的therapeutic approaches.Significance：药理学抑制H3 K27-去甲基化酶在人类脉络膜细胞促进表观遗传沉默的致癌TBXT，改变基因网络的生存至关重要，并代表了一个潜在的新疗法。
Expression of the transcription factor brachyury (TBXT) is normally restricted to the embryo, and its silencing is epigenetically regulated. TBXT promotes mesenchymal transition in a subset of common carcinomas, and in chordoma, a rare cancer showing notochordal differentiation, TBXT acts as a putative oncogene. We hypothesized that TBXT expression is controlled through epigenetic inhibition to promote chordoma cell death. Screening of five human chordoma cell lines revealed that pharmacologic inhibition of the histone 3 lysine 27 demethylases KDM6A (UTX) and KDM6B (JMJD3) leads to cell death. This effect was phenocopied by dual genetic inactivation of KDM6A/B using CRISPR/Cas9. Inhibition of KDM6A/B with a novel compound KDOBA67 led to a genome-wide increase in repressive H3K27me3 marks with concomitant reduction in active H3K27ac, H3K9ac, and H3K4me3 marks. TBXT was a KDM6A/B target gene, and chromatin changes at TBXT following KDOBA67 treatment were associated with a reduction in TBXT protein levels in all models tested, including primary patient-derived cultures. In all models tested, KDOBA67 treatment downregulated expression of a network of transcription factors critical for chordoma survival and upregulated pathways dominated by ATF4-driven stress and proapoptotic responses. Blocking the AFT4 stress response did not prevent suppression of TBXT and induction of cell death, but ectopic overexpression of TBXT increased viability, therefore implicating TBXT as a potential therapeutic target of H3K27 demethylase inhibitors in chordoma. Our work highlights how knowledge of normal processes in fetal development can provide insight into tumorigenesis and identify novel therapeutic approaches.Significance: Pharmacologic inhibition of H3K27-demethylases in human chordoma cells promotes epigenetic silencing of oncogenic TBXT, alters gene networks critical to survival, and represents a potential novel therapy.