TAG Synthesis and Oxidation Activated by YAP/TEAD Confers ROS Resistance in Cancer Stem Cells

Abstract Background Cancer stem cells (CSCs) are characterized by lower levels of reactive oxygen species (ROS), which contribute to radioresistance through mechanisms that remain unidentified. Methods Our study employed lipidomic analyses to investigate the lipid composition of lung CSCs, while concurrently utilizing RNA-seq analysis to assess the expression profile of CSCs. Gain and loss of functional studies were conducted to decipher the underlying molecular pathways. In addition, we performed immunohistochemical staining on clinical samples from human lung cancer patients and utilized transcriptome data to identify potential biomarkers for prognosis prediction. Results Lipidomic analyses unveiled that the predominant lipid in lung CSCs was triacylglycerol (TAG), which localized to peri-mitochondria lipid droplets. TAG acted as mitochondria-derived ROS scavengers, displaying higher oxidation levels compared to other lipids when exposed to H 2 O 2 . RNA-seq analysis revealed an upregulation of TAG synthesis enzymes (ACSL1/4, LPIN2, DGAT1/2, and PNPLA3) and the anti-ferroptosis arsenal GPX4 in CSCs. These molecular alterations were found to be relevant to CSC radioresistance, sphere formation, and tumor initiation. Furthermore, a six-gene TAG synthesis signature was identified, effectively predicting the prognosis and survival of lung cancer patients. Mechanistically, lung CSCs activated the YAP/TEAD pathway, enhancing the transcription of TAG synthesis genes, thereby playing a crucial role in both TAG synthesis and oxidation, ultimately conferring ROS resistance. Conclusions This comprehensive study enhances our understanding of the intricate mechanisms underlying CSC radioresistance. The identified pathways and signatures provide a promising foundation for the development of targeted therapies aimed at overcoming radioresistance in CSCs, with the potential to significantly improve patient outcomes in lung cancer treatment. Graphic Abstract