瘤缺氧通过降低TET活性导致DNA高甲基化
Bernard Thienpont1,2, Jessica Steinbacher3, Hui Zhao1,2
1Vesalius Research Center, VIB, Leuven, Belgium.
Nature
|August 18, 2016
概括
瘤缺氧或低氧降低了十-十一转位酶 (TET) 的活性,导致DNA高甲基化. 这种缺氧驱动的表观遗传变化促进了癌细胞的生长,可能占所有高甲基化事件的一半.
科学领域:
- 表观遗传学
- 癌症生物学
- 分子瘤学
背景情况:
- 瘤抑制基因的高甲基化使它们沉默,促进癌细胞的增殖.
- 在癌症中推动广泛的促进物过甲基化的机制尚不完全理解.
- 瘤缺氧是固体瘤的常见特征,与预后不佳有关.
研究的目的:
- 研究瘤缺氧对DNA甲基化模式的影响.
- 确定依赖氧气的十一转位 (TET) 酶在低氧诱导的高甲基化中的作用.
- 阐明缺氧对瘤抑制基因沉默的作用.
主要方法:
- 在不同氧气条件下的人类和小鼠癌细胞中评估TET酶活性 (低氧与正常氧).
- 在实验室和来自患者和小鼠模型的瘤组织中测量基因甲基化水平.
- 研究了缺氧,TET活性,DNA甲基化和瘤特征之间的关系.
主要成果:
- 瘤缺氧直接降低了依赖氧的TET酶的活性,而不依赖TET表达或代谢变化.
- 在缺氧下降的TET活性导致基因促进者的DNA高甲基化增加.
- 在患者的低氧瘤组织中,瘤抑制基因促进剂的甲基含量显著增加.
- 低氧诱导的超甲基化给癌细胞带来了选择性的生长优势,这可能解释了多达50%的观察到的超甲基化事件.
结论:
- 瘤缺氧是通过抑制TET酶活性对DNA甲基化的关键调节剂.
- 诱导瘤抑制基因的高甲基化有助于癌症的进展,可能是治疗点.
- 恢复瘤氧化可以逆转缺氧导致的表观遗传变化并抑制瘤生长.
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