TEFM switches mPTP opening via interaction with VDAC1 to drive mtDNA stress and ESCC progression

The mitochondrial transcription elongation factor (TEFM) is a pivotal regulator of mitochondrial DNA (mtDNA) replication and transcription. While cytoplasmic mtDNA release during cellular stress is implicated in chronic inflammation, the involvement of TEFM in cancer pathogenesis, particularly in esophageal squamous cell carcinoma (ESCC), and its mechanistic regulation of mtDNA-mediated oncogenesis remain largely unknown. Here, we found that TEFM is significantly upregulated in ESCC tumors versus adjacent normal tissues. TEFM overexpression promoted ESCC proliferation in vitro and in vivo. Mechanistically, we uncovered that TEFM drives mitochondrial dysfunction and mtDNA release by inducing mitochondrial permeability transition pore (mPTP) opening via VDAC1 complex formation, functioning as mitochondrial DAMPs to activate the TLR9 pathway and drive ESCC progression. Surprisingly, inhibiting the mPTP opening with cyclosporine A (CsA) and eliminating cytosolic mtDNA with DNase I significantly suppressed ESCC progression. Next, we established a 4NQO-induced spontaneous ESCC model using TLR9 −/− mice. Consistent with the above findings, our results confirmed that TLR9 knockout markedly inhibits the malignant progression of ESCC. Collectively, our findings reveal that TEFM-mediated mtDNA release via VDAC1-mPTP axis and TLR9 activation constitutes a novel oncogenic mechanism in ESCC, providing potential therapeutic targets for ESCC treatment.