High production of glutamine by CAFs in the TME. (A) Tukey boxplots displaying z-score values of GS mRNA expression in normal stroma and cancerous stroma from ovarian cancer and colon cancer (colon: normal, n = 4; cancer, n = 13. Ovary: normal, n = 8; cancer, n = 31). (B) Schematic of glutamine synthesis pathway. (C) Distributions of glutamine synthesis pathway scores and heatmaps displaying normalized gene expression in glutamine synthesis pathway in different cell types from mouse sarcoma scRNA-seq dataset. (D) Distributions of glutamine synthesis pathway scores and heatmaps displaying normalized gene expression in glutamine synthesis pathway in different cell types from human melanoma scRNA-seq dataset. (E) GS protein expression levels were determined by western blot in NFs (n = 2) and CAFs (n = 4). (F) Relative mRNA expression of genes (GS, Got1, Got2, and Bcat2) involved in glutamine synthesis pathway in NFs and CAFs. Data are shown as mean ± SEM and were analyzed by two-tailed, unpaired Student’s t test (E and F). ****P < 0.0001; ***P < 0.001; **P < 0.01; P > 0.05 not significant (ns). Source data are available for this figure: SourceData FS2.