https://blog.superhyydl.org/tags/dntp%E4%BB%A3%E8%B0%A2/Recent content in DNTP代谢 on Superhyydl's BlogHugozh-cnSun, 06 Sep 2026 00:00:00 +0000https://blog.superhyydl.org/reading/adaptive-regulation-of-dntp-homeostasis-confers-osimertinib/Sun, 06 Sep 2026 00:00:00 +0000https://blog.superhyydl.org/reading/adaptive-regulation-of-dntp-homeostasis-confers-osimertinib/<h2 id="一句话亮点">一句话亮点</h2> <p>EGFR突变肺癌对奥希替尼的耐药，靠的是“踩下RRM2刹车、同时启动RRM2B备用引擎”这套双轨调控，维持dNTP供给；打断这条代谢代偿通路，耐药进程就能被明显拖慢。</p> <h2 id="背景痛点">背景/痛点</h2> <p>奥希替尼是EGFR突变非小细胞肺癌的三代TKI，初始响应很好，但耐药几乎都会出现。已知的耐药机制主要是二次突变、旁路激活这些“老面孔”。但这篇研究问了个不一样的问题：药物压制EGFR信号后，细胞代谢层面发生了什么？这些代谢调整会不会反过来帮细胞活下来？</p> <p>dNTP是DNA复制和修复的原料，主要由核糖核苷酸还原酶（RNR）合成。RNR的催化大亚基是RRM1，小亚基有两个：RRM2在S期提供大部分dNTP，RRM2B在应激状态下被诱导出来“救场”。癌细胞增殖快，对dNTP供给高度依赖。如果EGFR抑制影响了dNTP生成，细胞能不能启动备用方案？备用方案又是怎么启动的？这就是本文的出发点。</p> <h2 id="推理链分步拆解">推理链分步拆解</h2> <h3 id="第一步奥希替尼到底对转录组干了什么">第一步：奥希替尼到底对转录组干了什么？</h3> <p>他们先用RNA-seq扫了一遍PC-9细胞（EGFR突变）在奥希替尼处理后的转录组变化。结果很明显：DNA复制、细胞周期、核苷酸代谢相关通路被显著抑制。其中RRM2和MYBL2是下降最明显的基因之一。</p> <p>WB验证发现RRM2蛋白确实大幅下降，而且是EGFR突变细胞特异的——EGFR野生型的A549细胞没有这种变化。这说明RRM2下调不是药物脱靶效应，而是突变EGFR信号被切断后的直接后果。</p> <p>那RRM2下降对dNTP池有什么影响？他们直接测了四种dNTP的含量，发现dCTP和dTTP这两类嘧啶核苷酸明显下降，而嘌呤类dATP/dGTP变化不大。这种选择性缺失，和RRM2主要负责嘧啶合成的功能是一致的。</p> <p>@方法论点评：RNA-seq做全局筛选找到候选靶点，再用WB和dNTP定量做因果验证——先“发现”再“锁定”，逻辑严密。嘧啶特异性下降也与RRM2的功能吻合，这是“表型-机制”匹配的关键证据。</p> <p>那RRM2下降是不是真的影响药物敏感性？他们过表达RRM2后做克隆形成实验，发现细胞对奥希替尼的耐受能力明显增强——RRM2水平本身就能决定细胞对药物的响应强度。</p> <p><img alt="Fig. 1：Osi suppresses RRM2 expression and reduces dNTP levels in PC-9 and HCC827 cells. A, Volcano plot showing gene expression changes in PC-9 cells after treatment with Osi. The x-axis denotes fold expression change, and the y-axis shows the P value of the change. Genes with a log2 fold ex- pression change ≥1 and an adjusted P &lt; 0.05 are highlighted. B, KEGG pathway enrichment analysis of genes downregulated by Osi in PC-9 cells. Pathways are ranked based on \x01log10 (P value). C, PC-9 and HCC827 cells were treated with the indicated con- centrations of Osi for 24 hours. Protein expression of RRM1 and RRM2 was assessed by WB, with GAPDH as a loading control. Results shown are representative of three independent experiments. D, Intracellular dNTP levels in PC-9 and HCC827 cells were quantified with or without 24-hour Osi treatment. Data are presented as mean ± SD from three independent biological replicates. E, PC-9 and HCC827 cells were transfected with FLAG-RRM2 for 48 hours. Protein ex- pression of FLAG and RRM2 was assessed by WB, with actin as a loading control. Results shown are representative of three independent experiments. F, Representative colony formation images of PC-9 and HCC827 cells were transfected with vector control or FLAG-RRM2 and treated with increasing concentrations of Osi. G, Quantification of colony density from F, illustrating the impact of RRM2 overexpression on cellular resistance to Osi. O/E, overexpression; NC, negative control." loading="lazy" src="https://blog.superhyydl.org/images/reading/adaptive-regulation-of-dntp-homeostasis-confers-osimertinib/figure-01.png"></p>