Investigating Effects of Oxygen Level on Krebs Cycle Dynamics in Glioblastoma Cell Lines U87 and LN18 with [2-13C] D-Glucose Utilizing 13C NMR Spectroscopy.*

The Krebs cycle, a central metabolic pathway in mitochondria, oxidizes acetyl-CoA derived from carbohydrates, fats, and proteins to produce NADH and FADH2. These molecules carry high-energy electrons to the electron transport chain, where they drive the synthesis of ATP through oxidative phosphorylation. This study explores the dynamics of the Krebs cycle in glioblastoma cells by using [2-13C] D-Glucose as a metabolic tracer in two glioblastoma cell lines, U87 and LN18. The cells were cultured in glucose-enriched media until reaching sufficient density and then seeded in regular media for 24 hours. Subsequently, one set of flasks was incubated for 48 hours in media containing [2-13C] D-Glucose, while the other set was maintained in regular media for 47 hours and exposed to [2-13C] D-Glucose for the final hour. This process was then repeated with a new set of flasks kept in hypoxic conditions for 48 hours in incubation prior to extraction. Both cells and media were collected and analyzed using 13C NMR spectroscopy to probe the metabolic fluxes of the Krebs cycle, providing detailed information into altered metabolic pathways in glioblastoma. Details of this will be presented.