Abstract 3079: AMPK-HIF-1α signaling enhances glucose-derived de novoserine biosynthesis to promote glioblastoma growth

Abstract

Abstract Cancer cells undergo cellular adaptation through metabolic reprogrammin to sustain survival and rapid growth under various stress conditions. However, it remains unknown how brain tumors modulate their metabolic flexibility in the naturally serine/glycine (S/G)-deficient brain microenvironment. We used a range of primary/stem-like and established glioblastoma (GBM) cell models in vitro and in vivo. To identify regulatory mechanisms of S/G deprivation induced metabolic flexibility, we employed high throughput RNA-sequencing, transcriptomic analysis, metabolic flux analysis, metabolites analysis, chromatin immunoprecipitation (ChIP), luciferase reporter, nuclear fractionation, cycloheximide-chase, and glucose consumption. The clinical significances were analyzed in the genomic database (GSE4290) and in human GBM specimens. The high throughput RNA-sequencing and transcriptomic analysis demonstrate that the de novo serine synthesis pathway (SSP) and glycolysis are highly activated in GBM cells under S/G deprivation conditions. Mechanistically, S/G deprivation rapidly induces reactive oxygen species (ROS)-mediated AMP-activated protein kinase (AMPK) activation and AMPK dependent hypoxia-inducible factor (HIF)-1α stabilization and transactivation. Activated HIF-1α in turn promotes expression of SSP enzymes phosphoglycerate dehydrogenase (PHGDH), phosphoserine aminotransferase 1 (PSAT1), and phosphoserine phosphatase (PSPH). In addition, HIF-1α-induced expression of glycolytic genes (GLUT1, GLUT3, HK2, and PFKFB2) promotes glucose uptake, glycolysis, and glycolytic flux to fuel SSP, leading to elevated de novo serine and glycine biosynthesis, NADPH/NADP+ ratio, and proliferation and survival of GBM cells. Analyses of human GBM specimens reveal that levels of overexpressed PHGDH, PSAT1, and PSPH are positively correlated with levels of AMPK T172 phosphorylation and HIF-1α expression and poor prognosis of GBM patients. Our findings reveal that metabolic stress-enhanced glucose-derived de novo serine biosynthesis is a critical metabolic feature of GBM cells and highlight the potential to target SSP for treating human GBM. Citation Format: Hye Jin Yun, Jong-Ho Lee. AMPK-HIF-1α signaling enhances glucose-derived de novoserine biosynthesis to promote glioblastoma growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3079.