Fig. 6

Serine and glycine de novo synthesis from gluconeogenesis. ¹³C₅-glutamine was administered to normal BEC or cancer cells in high or low glucose and high or low serine/glycine conditions. A Label enrichment (left) and total abundance normalized to protein and internal standard (right) are shown as mean ± SEM from four (A549 and H1299) or three (BEC) experiments. Statistical analysis was done for the most informative isotopologue (##). Group comparisons were performed by Two-way ANOVA with Tukey post-hoc analysis; B Relative label enrichment in serine (M + 3) normalized to M + 3 labeling of the precursor PEP, reflecting serine de novo synthesis from gluconeogenesis. Group comparisons were performed using Students’s t-test. *P < 0.05; **P < 0.01; ***P < 0.001; # versus high glucose. Ser/Gly, serine/glycine