Fig. 7: Activation of one-carbon metabolism is a unifying feature of cancer cachexia in mice.
a, Experimental set-up. Mice were divided into four groups: mice injected with PBS, healthy controls, no tumour (Ctrl, grey, no weight loss, n = 6 animals per group); mice orthotopically injected with Panc02 pancreatic cancer cells, mild cachexia (Panc02-Mild, blue, mean BW loss of 3%, n = 6 animals per group); mice orthotopically injected with 8025 pancreatic cancer cells divided into two groups, mild cachexia (8025-Mild, light green, mean body weight loss of 4%, n = 7 animals per group) and cachexia (8025-Cax, dark green, mean body weight loss of 10%, sarcopenia, n = 5 animals per group). On the day of euthanasia, mice were fasted for 6 h and injected with an isotopic tracer ([13C6]-glucose). Tissues (plasma, liver, eWAT and GC muscle) were collected exactly 1 h later. Tissues were then processed for tracer metabolomics. See also Extended Data Fig. 9. b,c, Relative mRNA expression levels of key enzymes of one-carbon metabolism and related pathways in liver (b) and GC muscle (c). d–g, Metabolite levels of one-carbon metabolism and related pathways in plasma (d), liver (e), GC muscle (f) and eWAT (g). Metabolite IDs as in the list in Fig. 3b. Statistical analysis based on raw data (2−ΔCt values and MS signal intensities, arbitrary units (AU)). h–o, Incorporation of labelled carbons from [13C6]-glucose into metabolites of the TCA cycle in GC muscles. Unlabelled metabolites are referred as M + 0 and isotopically labelled metabolites as M + X, where X represents the number of labelled carbon atoms. Data are presented as the percentage of total metabolite levels. Stacked bar graphs (h, j, l and n) show the overall isotopologue levels; bar graphs (i, k, m and o) show the levels of each individual isotopologue (citrate (h and i), succinate (j and k), fumarate (l and m) and malate (n and o)). Data are the mean ± s.e.m. Statistical analysis: one-way ANOVA with Dunnett’s post-hoc tests versus Ctrl or Kruskal–Wallis with Dunn’s post-hoc tests versus Ctrl. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 compared with Ctrl.
