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RAF 抑制剂通过直接激活 GCN2 来激活综合应激反应
Rebecca Gilley1, Andrew M Kidger2,3, Graham Neill4
1Signalling Programme, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK. becky.gilley@babraham.ac.uk.
Nature communications
|November 17, 2025
概括
矛盾的是,RAF抑制剂激活GCN2,一种压力激酶,独立于ERK1/2.2,启动综合应激反应 (ISR). 这种非目标效应可能会影响癌细胞对RAF抑制剂的反应.
科学领域:
- 分子生物学分子生物学
- 细胞信号传输 细胞信号传输
- 癌症治疗方法 癌症治疗方法
背景情况:
- 由RAF抑制剂 (RAFi) 激活野生型RAF是一种已知的目标效应.
- 综合应激反应 (ISR) 途径,涉及eIF2α酸化,调节细胞应激.
- 展开的蛋白质反应 (UPR) 是ISR的一个关键组成部分.
研究的目的:
- 研究RAF抑制剂激活ISR的机制.
- 确定RAFi诱导的ISR激活是否依赖于已知的ISR激活器,如PERK.
- 探索GCN2激酶在RAFi介导的ISR激活中的作用及其潜在的临床相关性.
主要方法:
- 用各种RAF抑制剂 (RAFi) 治疗细胞.
- 对ATF4和CHOP表达的分析,主要的ISR标志物.
- 抑制PERK,GCN2 (使用抑制剂,RNAi或淘汰),以及ISRIB.
- 在体外和细胞激活测定GCN2.
- GCN2的局部定向突变发生 (激酶死亡和守门员突变).
- 对RAFi-GCN2相互作用的机制结构建模.
主要成果:
- RAFi诱导ERK1/2-独立的UPR激活,包括ATF4和CHOP表达,依赖于eIF2α.
- 通过PERK抑制,RAFi诱导的ATF4/CHOP表达不会逆转,但需要GCN2激活.
- 在实验室和细胞中,RAFi直接激活GCN2激酶,呈现一个钟形的度-反应曲线.
- 抑制或对抗GCN2可以逆转RAFi诱导的ATF4/CHOP表达,证实了GCN2的重要作用.
- RAFi直接与GCN2激酶域结合,这是门卫突变研究和结构建模所证明的.
结论:
- RAF 抑制剂通过直接,悖论性的 GCN2 激酶激活激活ISR.
- 这种GCN2介导的ISR激活是RAFi的非目标效应,独立于ERK1/2信号.
- 这些发现表明,RAFi激活GCN2可能会影响瘤细胞存活率和临床结果.
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