Smohaze‐Upregulated RFWD3 Competes with TRIM24 to Stabilize TREX1 and Reduce Cytosolic dsDNA in Non‐Small Cell Lung Cancer

The E3 ubiquitin ligase RFWD3 binds the exonuclease TREX1 and protects it from TRIM24‐mediated ubiquitination and degradation, leading to the eradication of intracellular dsDNA, inhibition of the cGAS‐STING pathway, and immunosuppressive microenvironment of lung cancer. Exposure to cigarette smoke and haze (PM2.5) upregulate RFWD3 via transcription factor AhR, while inhibition of RFWD3 enhances the therapeutic efficacy of PD‐L1 blockade, providing a potential approach to tackle smohaze‐induced lung cancer. Abstract The three‐prime repair exonuclease 1 (TREX1), an intracellular double‐stranded DNA (dsDNA) degrader that inhibits the stimulator of interferon (IFN) genes (STING) pathway, is turned over by E3 ligase TRIM24‐mediated proteasomal degradation. To uncover TREX1‐stabilizers in non‐small cell lung cancer (NSCLC), mass spectrometry is conducted, and 374 candidates are identified, with the RING Finger and WD Repeat Domain 3 (RFWD3) as a TREX1 protector that sequesters it from TRIM24. Overexpression of RFWD3 promotes tumor growth with increased myeloid‐derived suppressor cells (MDSCs), while inhibition of RFWD3 increases intracellular dsDNA levels, activates the STING‐IFN signaling, decreases MDSCs, and enhances the efficacy of PD‐L1 blockade in murine NSCLC models. Furthermore, smoker patients have higher RFWD3 levels than non‐smoker patients, and cigarette smoke extract, PM2.5, and benzo(a)pyrene upregulatesRFWD3 via transcription factor aryl hydrocarbon receptor. These results indicate a role of RFWD3 in tobacco smoke and haze (smohaze)‐promoted immune evasion, inhibition of which activates STING‐IFN signaling and synergizes with immune checkpoint inhibitors in NSCLC. The E3 ubiquitin ligase RFWD3 binds the exonuclease TREX1 and protects it from TRIM24-mediated ubiquitination and degradation, leading to the eradication of intracellular dsDNA, inhibition of the cGAS-STING pathway, and immunosuppressive microenvironment of lung cancer. Exposure to cigarette smoke and haze (PM 2.5 ) upregulate RFWD3 via transcription factor AhR, while inhibition of RFWD3 enhances the therapeutic efficacy of PD-L1 blockade, providing a potential approach to tackle smohaze-induced lung cancer. Abstract The three-prime repair exonuclease 1 (TREX1), an intracellular double-stranded DNA (dsDNA) degrader that inhibits the stimulator of interferon (IFN) genes (STING) pathway, is turned over by E3 ligase TRIM24-mediated proteasomal degradation. To uncover TREX1-stabilizers in non-small cell lung cancer (NSCLC), mass spectrometry is conducted, and 374 candidates are identified, with the RING Finger and WD Repeat Domain 3 (RFWD3) as a TREX1 protector that sequesters it from TRIM24. Overexpression of RFWD3 promotes tumor growth with increased myeloid-derived suppressor cells (MDSCs), while inhibition of RFWD3 increases intracellular dsDNA levels, activates the STING-IFN signaling, decreases MDSCs, and enhances the efficacy of PD-L1 blockade in murine NSCLC models. Furthermore, smoker patients have higher RFWD3 levels than non-smoker patients, and cigarette smoke extract, PM 2.5, and benzo(a)pyrene upregulatesRFWD3 via transcription factor aryl hydrocarbon receptor. These results indicate a role of RFWD3 in tobacco smoke and haze (smohaze)-promoted immune evasion, inhibition of which activates STING-IFN signaling and synergizes with immune checkpoint inhibitors in NSCLC. Advanced Science, Volume 12, Issue 48, December 29, 2025.