392 Targeting One-Carbon Metabolism in Brain Cancer

Abstract

OBJECTIVES/GOALS: Glioblastoma (GBM) is the most malignant brain tumor in adults and remains incurable with an average survival of 15 months after diagnosis. There is great need for treatment options without side effects that are devastating to the quality of life for patients. GBM tumors can circumvent cellular damage by upregulating antioxidant production. METHODS/STUDY POPULATION: Highly aggressive tumors tend to exhibit increased oxidative metabolism, and thus rely on a mechanism to eliminate reactive oxygen species (ROS) in order for cells to evade autophagy and cell death. We propose that recurrent GBM cells achieve this is by promoting methionine metabolism, upregulating glutathione production and preventing ROS accumulation. We investigated the expression of AHCY and MAT2A, two key enzymes in the methionine pathway, at the gene and protein level in both GBM and non-GBM tissues. We probed for markers of cell death following pharmacological inhibition and siRNA knockdown, and performed metabolite-mediated rescue experiments. Finally, we evaluated changes in cellular respiration using the Seahorse XFe96 real-time mitochondrial stress test following inhibitor treatment. RESULTS/ANTICIPATED RESULTS: The selective AHCY inhibitor markedly reduced cell viability in different cancer cell types, but significantly reduced cell viability in recurrent GBM cells compared to newly diagnosed GBM (p=.009; MD: -0.828, 95% CI -1.350 to -0.306) and normal astrocytes (p=.073; MD: -0.609, 95% CI -1.305 to 0.085). AHCY and MAT2a protein expression appeared to be higher in GBM cells compared to normal astrocytes, medulloblastoma cells and other cancer cell lines. Genetic knockdown of AHCY and MAT2A demonstrated reduced cell viability, increased Caspase, SOD2, LC3-II and Transferrin receptor expression. Acute treatment with the AHCY inhibitor induced cell death, markedly reduced oxygen consumption rate and ablated spare respiratory capacity in recurrent GBM cells compared to newly diagnosed GBM cells. DISCUSSION/SIGNIFICANCE: Oxidative damage was induced following interference with key methionine pathway enzymes by pharmacological inhibition, while a similar concentration of drug largely preserved normal astrocyte viability. These results point to a novel targetable mechanism of disease progression and expand the realm of treatment options for recurrent GBM.