Mitochondrial DNA Sensing Reshapes the Tumor Immune Microenvironment via Cooperative cGAS-STING Activation and Ferroptosis

Abstract

Abnormal release of mitochondrial DNA (mtDNA) and innate immune sensing play key roles in tumor immune regulation, but how they work together with ferroptosis is still unclear. This study aims to clarify the molecular mechanism of how mtDNA reshapes the tumor immune microenvironment in coordination with ferroptosis through activating the cGAS-STING signaling pathway, as well as its anti-tumor potential. By creating tumor cell mitochondrial stress models and using CRISPR-Cas9 gene knockout, lipid peroxidation detection, single-cell transcriptome analysis, and mouse syngeneic tumor models, we systematically assessed how mtDNA release affects the cGAS-STING pathway and ferroptosis. The results showed that mitochondrial stress-induced cytoplasmic mtDNA release significantly activates the cGAS-STING pathway, upregulates type I interferons and chemokines like CXCL10, and promotes lipid peroxidation and ferroptosis by suppressing the xCT/GPX4 antioxidant axis. Ferroptotic tumor cells further release damage-associated molecules like HMGB1 and ATP, enhancing dendritic cell maturation and CD8⁺ T cell tumor infiltration, forming a positive feedback loop of immune activation. In mouse melanoma models, combining mtDNA release with ferroptosis significantly inhibited tumor growth and extended survival, showing better results than either intervention alone. This study reveals a new mechanism where mtDNA sensing collaborates with ferroptosis via the cGAS-STING pathway to reshape the tumor immune microenvironment, providing a theoretical basis and potential targets for developing anti-tumor immunotherapies that jointly regulate innate immunity and ferroptosis.