The low-dose CHK1 inhibitor prexasertib triggers VDAC1 dephosphorylation to activate mtDNA-STING signaling and synergize immunotherapy

作者：Yu Fu, Xiaoyan Kang, Wenting Li, Zanhong Wang, W. Luo, Bin Yang, Yaoyuan Cui, Funian Lu, Tianyu Qin, Xingyuan Hu, Jingjing Yin, Zhiheng Li, Junpeng Fan, Beibei Wang, Gang Chen, Rourou Xiao, Zhiqiang Han, Ensong Guo, Qin Xu · 发表于：Cell Reports · 年份：2025 · DOI：10.1016/j.celrep.2025.115605 · 被引用次数：7 · 研究领域：interferon and immune responses、RNA modifications and cancer、Ubiquitin and proteasome pathways

CHK1 inhibitors exhibit dose-limiting toxicity despite potent tumor cytotoxicity in clinical trials. Here, we reveal that low-dose prexasertib induces mtDNA damage by impairing repair machinery, triggering cytosolic mtDNA release via VDAC1 to activate STING-mediated innate immunity. Mechanistically, prexasertib blocks CHK1 phosphorylation and competitively recruits Nek1 kinase, thereby activating the ATR/CHK1 signaling cascade. Consequently, it disrupts the phosphorylation of VDAC1 by Nek1 kinase at T107 and promotes the formation of VDAC1 oligomers, where mtDNA exits. In vivo, low-dose prexasertib exhibits immune-modulatory effects and synergizes safely with immune checkpoint blockade at subtherapeutic doses. Our findings establish reduced-dose CHK1 inhibition as a strategy to amplify immunotherapy efficacy while circumventing systemic toxicity, providing a translatable framework for optimizing therapeutic windows in clinical oncology.