Single-Cell and Spatial Transcriptomics Reveal CHCHD3 as a Therapeutic Target to Activate cGAS-STING and Overcome Immunosuppression in Lung Adenocarcinoma

A substantial proportion of treatment-naive lung adenocarcinoma (LUAD) patients exhibit intrinsic resistance to neoadjuvant chemoimmunotherapy, highlighting the need for mechanism-driven therapeutic strategies. Here, we performed integrated single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics on clinical specimens from the CheckMate 816 trial to define the tumor immune microenvironment (TIME) dynamics associated with therapy resistance. The scRNA-seq data revealed distinct TIME features in non-responders to neoadjuvant chemoimmunotherapy, characterized by the upregulation of CHCHD3. Mechanistically, CHCHD3 acted as a negative regulator of innate immunity by sequestering cGAS in mitochondria. This interaction between the CHCHD3 domain and the cGAS catalytic core reduced the cytosolic cGAS pool, thereby blunting STING-dependent signaling. Consequently, CHCHD3 knockout restored CXCL5/CXCL1 production, reduced M2-like tumor-associated macrophages, and promoted CD8+ T cell infiltration. Integrated virtual and functional drug screening identified TN4510 as a small molecule that disrupts the CHCHD3-cGAS interface. TN4510 treatment effectively restored STING signaling and synergized with chemoimmunotherapy to suppress tumor growth in preclinical models. Together, these findings reveal that CHCHD3 drives chemoimmunotherapy resistance by sequestering cGAS to limit STING activation. Targeting CHCHD3 with TN4510 restores antitumor immunity, offering a translatable strategy to overcome treatment resistance in LUAD.