SREBP-1 upregulates lipophagy to maintain cholesterol homeostasis in brain tumor cells - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Access content directly
Journal Articles Cell Reports Year : 2023

SREBP-1 upregulates lipophagy to maintain cholesterol homeostasis in brain tumor cells

Abstract

Cholesterol is a structural component of cell membranes. How rapidly growing tumor cells maintain mem-brane cholesterol homeostasis is poorly understood. Here, we found that glioblastoma (GBM), the most lethal brain tumor, maintains normal levels of membrane cholesterol but with an abundant presence of cholesteryl esters (CEs) in its lipid droplets (LDs). Mechanistically, SREBP-1 (sterol regulatory element-binding protein 1), a master transcription factor that is activated upon cholesterol depletion, upregulates critical autophagic genes, including ATG9B, ATG4A, and LC3B, as well as lysosome cholesterol transporter NPC2. This upregu-lation promotes LD lipophagy, resulting in the hydrolysis of CEs and the liberation of cholesterol from the ly-sosomes, thus maintaining plasma membrane cholesterol homeostasis. When this pathway is blocked, GBM cells become quite sensitive to cholesterol deficiency with poor growth in vitro. Our study unravels an SREBP-1-autophagy-LD-CE hydrolysis pathway that plays an important role in maintaining membrane cholesterol homeostasis while providing a potential therapeutic avenue for GBM.
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hal-04279038 , version 1 (10-11-2023)

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Feng Geng, Yaogang Zhong, Huali Su, Etienne Lefai, Shino Magaki, et al.. SREBP-1 upregulates lipophagy to maintain cholesterol homeostasis in brain tumor cells. Cell Reports, 2023, 42 (7), pp.112790. ⟨10.1016/j.celrep.2023.112790⟩. ⟨hal-04279038⟩
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