Non-small cell lung cancer-associated Keap1 mutations lead to epigenetic reprogramming and tumorigenesis through CHD6 stabilization

The E3 ubiquitin ligase substrate recognition subunit Keap1 mediates the ubiquitination and degradation of the oxidative stress transcription factor NRF2. Approximately 30% of non-small cell lung cancers (NSCLCs) harbor inactivating mutations in Keap1 or activating mutations in NRF2, both of which lead to the stabilization of NRF2 and activation of the downstream antioxidant pathway. Recent studies have found that the oncogenic effects of Keap1 and NRF2 mutations are not entirely equivalent, suggesting that Keap1 may have other regulatory substrates. In previous work, we used affinity immunopurification and mass spectrometry to identify the epigenetic regulator CHD6 as a Keap1-interacting protein, with Keap1 mediating the ubiquitination and degradation of CHD6. NSCLC-derived Keap1 mutants lost the ability to bind and ubiquitinate CHD6. Additionally, CHD6 interacts with NRF2 and promotes the enrichment of NRF2 at the promoters of its target genes, enhancing their transcription.This project aims to elucidate the mechanism by which the abnormal accumulation of CHD6 protein, due to disruption of its Keap1-mediated degradation, drives epigenetic reprogramming in the context of Keap1-mutant NSCLC development and progression. The findings will provide a theoretical basis for the development of NRF2 pathway inhibitors targeting CHD6 as a drug target. RNA seq of Human non-small cell lung cancer cells in control and knock out CHD6 group

E3泛素连接酶底物识别亚基Keap1可介导氧化应激转录因子核因子E2相关因子2（NRF2）的泛素化与降解。约30%的非小细胞肺癌（NSCLCs）患者携带有Keap1失活突变或NRF2激活突变，两类突变均可导致NRF2稳定积累并激活下游抗氧化通路。近期研究发现，Keap1与NRF2突变的致癌效应并不完全等同，这提示Keap1可能存在其他调控底物。本团队前期研究通过亲和免疫纯化结合质谱技术，将表观遗传调控因子CHD6鉴定为Keap1的互作蛋白，并证实Keap1可介导CHD6的泛素化与降解。源自非小细胞肺癌的Keap1突变体丧失了结合并泛素化CHD6的能力。此外，CHD6可与NRF2相互作用，并促进NRF2在其靶基因启动子区域的富集，从而增强靶基因的转录活性。本项目旨在阐明：因Keap1介导的降解通路受损而出现异常积累的CHD6蛋白，如何驱动Keap1突变型非小细胞肺癌发生发展过程中的表观遗传重编程。本研究结果将为以CHD6为药物靶点的NRF2通路抑制剂开发提供理论依据。本数据集包含人非小细胞肺癌细胞对照组与CHD6敲除组的RNA测序（RNA-seq）数据。