Fig. 2.

Compensatory elevation of serine and glycine levels enables GBM cells to survive glutamine starvation. See also Additional File 2: Supplemental Fig. 2. a U87 and T98 GBM cells were grown in the presence or absence of glucose (Glc) and/or glutamine (Gln). Cell numbers were counted over time. Data represent the mean ± SEM of three independent experiments. b Heatmap representation of a two-dimensional hierarchical clustering of amino acids identified as differentially expressed among U87 and T98 GBM cells which were grown with or without glutamine for 48 h. Each column represents a treatment group per cell line and each row represents an amino acid. c Intracellular levels of glutamine, glutamate, glycine, methionine, and serine in U87 and T98 GBM cells which were grown with and without glutamine for 48 h. Data represent the mean ± SEM of three independent experiments (statistically significant with **p < 0.01)