2426 - MGLL-Driven Ferroptosis via ATG9A-Mediated Lipid Mobilization Enhances Radiosensitivity in NSCLC
Presenter(s)
Y. Ma1, J. Yuan2, X. Wang1, B. Tian2, J. Yu3, and D. Chen4; 1Shandong university, Department of Radiation Oncology and Shandong Provincial Key Laboratory of Precision Oncology, Jinan, Shandong, China, 2Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China, 3Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences Department of Radiation Oncology, Jinan, Shandong, China, 4Department of Radiation Oncology and Shandong Provincial Key Laboratory of Precision Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
Purpose/Objective(s): Lipid metabolism reprogramming has drawn significant attention due to its pivotal role in tumor initiation, progression, and therapeutic resistance. Monoacylglycerol lipase (MGLL), a key enzyme in lipid metabolism, hydrolyzes monoacylglycerols to release free fatty acids (FAs). Additionally, mitochondrial FA ß-oxidation is a major source of cellular reactive oxygen species (ROS), which can induce lipid peroxidation and ultimately trigger ferroptosis. In this study, we aim to elucidate the essential role of MGLL in mediating the radiosensitivity of non-small cell lung cancer (NSCLC).
Materials/Methods: Metabolomics via UPLC-MS/MS revealed lipid metabolism changes of NSCLC cells after radiotherapy (RT). TMT quantitative proteomics identified MGLL as a key protein in NSCLC radioresistant cell lines. IHC analysis of NSCLC tissues showed differential MGLL expression and lipid content. MGLL knockout and overexpression cell lines were used to assess radiosensitivity via Flow Cytometry, Immunofluorescence (IF), comet and colony formation assays. Co-IP-MS identified MGLL-interacting proteins. RNA-Seq and GSEA highlighted ferroptosis-related pathways. Mitochondrial OCR was measured using the Oroboros O2K system.
Results: The study demonstrated MGLL expression was downregulated in radioresistant cell lines compared to their parental counterparts. Clinical samples revealed that patients with higher MGLL expression exhibited better responses to RT. Functional experiments confirmed MGLL overexpression in NSCLC cells amplified the radiosensitivity. Moreover, by reintroducing either wild-type MGLL or enzyme-active-site mutant plasmids into MGLL knockout cells, we proved that the radiosensitizing effect of MGLL is dependent on its enzymatic activity. Additionally, treatment with 2-Arachidonoylglycerol (2-AG), a substrate of MGLL, sensitized the anti-tumor effects of RT. To identify the interacting networks of MGLL, we performed IP-MS and identified ATG9A as an interacting partner. Subsequent IF studies showed that MGLL altered ATG9A localization, promoting its accumulation on lipid droplets rather than small vesicles. Furthermore, ATG9A mobilizes FAs, hydrolyzing by MGLL, to the mitochondria, where it drives fatty acid ß-oxidation and oxidative phosphorylation. Ultimately, overexpression of MGLL in cells post- RT led to a significant increase in ROS and ferroptosis levels, which enhanced the radiosensitivity of NSCLC cells.
Conclusion: Our study elucidates the MGLL/ATG9A/ROS axis following RT. MGLL modulates the subcellular localization of ATG9A, facilitating the translocation of fatty acids to the mitochondria, thereby promoting ferroptosis in cells. Augmenting MGLL expression may represent a promising strategy to enhance radiosensitivity in clinical RT.