CROT overactivation within peroxisomes confers chemoresistance to non-small cell lung cancer by targeting fatty acid oxidation-Nrf2-ferroptosis resistance axis

A key factor that limits the therapeutic benefits for non-small cell lung cancer (NSCLC) patients is chemoresistance. Even so, a detailed understanding of the process involved in chemoresistance acquisition and development at molecular level in NSCLC is still lacking. Here, we established chemo-resistant NSCLC cells with obvious resistance to vincristine and paclitaxel and found the abnormal up-regulation of Carnitine O-Octanoyltransferase (CROT) in these cells by means of transcriptomics. In vitro and in vivo experiments demonstrate that the survival of NSCLC cells, especially chemosensitivity, including sensitivity to chemotherapeutics beyond vincristine and paclitaxel, was markedly influenced by CROT expression, and CROT silencing even reversed chemoresistance in NSCLC. Mechanistically, CROT is overactivated within peroxisomes in chemo-resistant NSCLC cells and drives chemoresistance relying on its involvement in lipid metabolism and oxidative stress processes. By mediating the production of Hydrogen Peroxide (H₂O₂) and reactive oxygen species (ROS), CROT stabilizes eryth-like-2 associated factor 2 (Nrf2) via preventing its ubiquitination and degradation, leading to more nuclear translocation of Nrf2, thereby inhibiting chemotherapy stress-induced ferroptosis. Accordingly, fatty acid oxidation inhibitors or ferroptosis activators rendered NSCLC cells increased sensitivity to chemotherapy in vitro and in vivo. Clinically and encouragingly, the aberrant up-regulation of CROT and Nrf2 was observed in chemo-resistant NSCLC tumor tissues and patients with higher CROT and/or Nrf2 level possessed a poor outcome. In sum, our study identifies CROT as a key promoter to drive chemoresistance of NSCLC cells by targeting fatty acid oxidation-Nrf2-ferroptosis resistance axis. The targeted inhibition of this axis and associated components individually or in cascades combined with chemotherapy may be exploited in avoiding or overcoming chemoresistance in NSCLC.