Rnf20 links the DNA damage response and metabolic rewiring in lung cancer through HIF1α [ChIP-Seq_P2t_Rnf20_Het_shHIF1A]. Rnf20 links the DNA damage response and metabolic rewiring in lung cancer through HIF1α [ChIP-Seq_P2t_Rnf20_Het_shHIF1A]

Defective DNA repair and metabolic rewiring are highly intertwined in promoting the development and progression of cancer. However, the molecular players at the interface of these processes remain largely unexplored. Here we show that the Rnf20-HIF1α axis links the DNA damage response and metabolic reprogramming in lung cancer. Haploinsufficiency of Rnf20, catalyzing histone H2B monoubiquitylation (H2Bub1), dramatically increases the occurrence of spontaneous lung adenocarcinoma and small cell lung carcinoma (SCLC) in mice. Mechanistically, ablation of a single Rnf20 allele resulted in insufficient Rnf20-H2Bub1-p53-mediated control and induced pronounced defects in DNA repair, increased cell growth, epithelial-to-mesenchymal transition (EMT), and metabolic rewiring via HIF1α-mediated RNA polymerase II promoter-proximal pause release, which was independent of H2Bub1. Importantly, RNF20 levels are decreased in lung adenocarcinoma and SCLC patients, and this decrease negatively correlates with the expression of HIF1α target genes, suggesting HIF1α inhibition as a promising therapeutic approach for lung cancer patients with decreased RNF20 activity. Overall design: MLE12 ctrl, Rnf20+/- , ctrl+shHif1a and Rnf20+/-+shHif1a cells were harvested for Pol II chipseq.

DNA修复缺陷与代谢重编程在促进癌症发生与进展的过程中存在高度交织的关联。然而，介导这两类过程交互界面的分子调控因子在很大程度上仍未被探明。本研究揭示，Rnf20-缺氧诱导因子1α（HIF1α）通路可连接肺癌中的DNA损伤应答与代谢重编程过程。催化组蛋白H2B单泛素化（H2Bub1）的Rnf20发生单倍体不足时，可显著提升小鼠自发性肺腺癌与小细胞肺癌（SCLC）的发生率。从机制层面来看，单个Rnf20等位基因的缺失会导致Rnf20-H2Bub1-p53介导的调控功能不足，进而诱发显著的DNA修复缺陷、细胞增殖加速、上皮间质转化（EMT），并通过HIF1α介导的RNA聚合酶II启动子近端暂停释放过程引发代谢重编程，且该过程不依赖于H2Bub1。值得注意的是，肺腺癌与SCLC患者体内的RNF20表达水平均出现下调，且该下调与HIF1α靶基因的表达呈负相关，这提示抑制HIF1α可作为RNF20活性降低的肺癌患者的潜在治疗策略。实验设计概述：收集MLE12对照组、Rnf20单倍体不足组、对照组+shHif1a干扰组以及Rnf20单倍体不足组+shHif1a干扰组的细胞，用于进行RNA聚合酶II（Pol II）染色质免疫共沉淀测序（ChIP-seq）。