Abstract

Background Mitophagy is a mitochondrial quality control process that maintains cellular homeostasis in cancer, yet whether its dysregulation can be exploited to induce tumor immunogenicity remains unclear. Methods We integrated pancancer single-cell transcriptomic analyses with genetic perturbation strategies in hepatocellular carcinoma models, including CRISPR/Cas9-mediated gene depletion, in vivo syngeneic tumor systems, and RNA-based lipid nanoparticle delivery. Mechanistic investigations combined mitochondrial functional assays, imaging-based mitophagy analysis, flow cytometry, and transcriptional profiling, together with evaluation of immune checkpoint blockade responses in preclinical and clinical cohorts. Results We identify translocase of the outer mitochondrial membrane 40 (TOMM40) as a mitochondrial import gatekeeper that restrains PINK1-Parkin-dependent mitophagy. Loss of TOMM40 induces catastrophic mitochondrial dysfunction and triggers a lethal form of hyperactivated mitophagy. This process is immunogenic and converts immune-cold tumors into immune-inflamed states characterized by enhanced CD8 + T-cell infiltration and activation. Mechanistically, TOMM40 deficiency leads to intracellular reactive oxygen species accumulation, which activates NF-κB signaling and drives upregulation of major histocompatibility complex class I antigen presentation machinery, thereby increasing tumor visibility to cytotoxic T cells. In parallel, TOMM40 loss induces programmed death-ligand 1 upregulation, establishing an adaptive immune resistance program. Functionally, TOMM40-deficient tumors exhibit markedly increased responsiveness to immune checkpoint blockade and generate systemic antitumor immune protection. Clinically, a TOMM40-loss transcriptional signature is associated with improved immunotherapy outcomes across multiple independent patient cohorts. Conclusions TOMM40 functions as a mitochondrial immune checkpoint that controls the threshold of immunogenic mit