Activation of LXR reprograms central carbon metabolism of tumor cells.Figure 5U87 cells were treated with DMSO or LXR623 20 µM for 24h. Thereafter, cells were processed for polar metabolite analysis by LC/MS. In panel A, -log10 p-values and log2 fold change (fc) are shown. Highlighted in red are TCA - cycle related metabolites. In panel B, metabolite pathway analysis was performed. Highlighted (red dots) are the tricarboxylic acid cycle and pyruvate metabolism as significant and impactful pathways altered by LXR623 treatment. U87 cells were treated as in A. Shown are the levels of TCA-cycle metabolites. U87 cells were incubated in DMEM (devoid of phenol red, glucose, pyruvate and glutamine) supplemented with 25 mM U-13C-glucose, 4 mM glutamine and 1.5% dialyzed FBS in the presence or absence of 20 µM LXR623 for 24 hours. Cells were then harvested for LC/MS analysis. The fractions of each different isotopologue of each metabolite were calculated (percentage of the entire pool). Shown are the isotopologues of the TCA cycle intermediates labeled by glucose carbons and non-labeled isotopologues (m+0). U87 cells were incubated in DMEM (devoid of phenol red, glucose, pyruvate and glutamine) supplemented with 25 mM U-13C-glucose, 4 mM glutamine and 1.5% dialyzed FBS in the presence or absence of 20 µM LXR623 for 24 hours. Cells were then harvested for LC/MS analysis. The fractions of each different isotopologue of each metabolite were calculated (percentage of the entire pool). Shown are the isotopologues of the TCA cycle intermediates labeled by glucose carbons and non-labeled isotopologues (m+0). U87 cells were incubated in DMEM (devoid of phenol red, glucose, pyruvate and glutamine) supplemented with 25 mM U-13C-glucose, 4 mM glutamine and 1.5% dialyzed FBS in the presence or absence of 20 µM LXR623 for 24 hours. Cells were then harvested for LC/MS analysis. The fractions of each different isotopologue of each metabolite were calculated (percentage of the entire pool). Shown are the isotopologues of non-essential aminoacids (glutamatic acid and aspartic acid). U87 cells were incubated in DMEM (devoid of phenol red, glucose, pyruvate and glutamine) supplemented with 25 mM U-13C-glucose, 4 mM glutamine and 1.5% dialyzed FBS in the presence or absence of 20 µM LXR623 for 24 hours. Cells were then harvested for LC/MS analysis. The fractions of each different isotopologue of each metabolite were calculated (percentage of the entire pool). Shown are the isotopologues of non-essential aminoacids (glutamatic acid U87 cells were incubated in DMEM (devoid of phenol red, glucose, pyruvate and glutamine) supplemented with 25 mM U-13C-glucose, 4 mM glutamine and 1.5% dialyzed FBS in the presence or absence of 20 µM LXR623 for 24 hours. Cells were then harvested for LC/MS analysis. The fractions of each different isotopologue of each metabolite were calculated (percentage of the entire pool). Shown are the isotopologues of glutathione and nucleotides. U87 cells were incubated in DMEM (devoid of phenol red, glucose, pyruvate and glutamine) supplemented with 25 mM U-13C-glucose, 4 mM glutamine and 1.5% dialyzed FBS in the presence or absence of 20 µM LXR623 for 24 hours. Cells were then harvested for LC/MS analysis. The fractions of each different isotopologue of each metabolite were calculated (percentage of the entire pool). Graphical depiction of glucose carbon tracing. Shown are the 13C-Glucose carbons (red) and how they are transferred amongst molecules of the TCA cycle, amino acid biosynthesis and purine/pyrimidine synthesis. Glucose is metabolized to pyruvic acid (m+3) (three carbons labeled). When glucose is oxidized in the TCA cycle (m+2) citric acid is produced (two carbons labeled). When glucose is used for anaplerosis, citric acid (m+3) is produced (three carbons labeled). Glucose carbons are harnessed for the biosynthesis of glutathione either through the serine/glycine pathway or the TCA cycle via oxoglutaric acid and glutamate. The graphical presentation is representative for only one turn of the TCA cycle. U87 cells were treated with DMSO or LXR623 20 µM for 24h. Thereafter, cells were processed for polar metabolite analysis by LC/MS. Shown are the levels of NAD and NADH2.