Fig. 5: Serine and glycine are crucial for effective immunotherapy, with the serine synthesis pathway associated with T cell dysfunction in cancer patients.
a Heatmap depicting the log2 fold-change (FC) values of differentially expressed genes in T cells and E0771 cancer cells from tumors treated wither with IgG (2 µg/µl) or αPD-1 (2 µg/µl). b TIDE analyses were conducted on PHGDH expression within T cell dysfunction signatures associated with improved survival in patients with triple negative breast cancer. TGCA, The Cancer Genome Atlas. p-values are calculated by two-sided Wilcoxon rank-sum test. OS, overall survival. c Cytotoxicity assay by CD8 + T cells expressing sgRNAs targeting PHGDH or SHMT1 and co-cultured with GP33–41-pulsed E0771 cells for 24 hrs. Data represent mean ± SD from biologically independent experiments (n = 3); p-values were calculated using a two-tailed unpaired t-test. **p < 0.01. Source data including exact p-values are provided as Source Data file. d GzmB and IFNγ secretion by CD8 + T cells transduced with sgRNAs against PHGDH or SHMT1 and co-cultured with GP33–41-pulsed E0771 cells for 24 hrs. Data represent mean ± SD from biologically independent experiments (n = 4); p-values were calculated using a two-tailed unpaired t-test. **p < 0.01; ***p < 0.001. Source data including exact p-values are provided as Source Data file. e tRNA aminoacylation assay in T cells expressing sgRNAs targeting PHGDH or SHMT1 and co-cultured with GP33–41-pulsed E0771 cells. Cells were separated by size (as described in Supplementary Fig. 6c) after 24 hours of co-culture. Ser-tRNAs, Gly-tRNAs and control Leu-tRNAs were analyzed. f Female C57BL/6 J mice (7–8 weeks old; n = 7 per group) were orthotopically injected with E0771 cells. Seven days later, mice were switched to either a control diet or a serine/glycine‑free ( − SG) diet. Once tumors became palpable, animals in each dietary group received intraperitoneal injections of control IgG or anti‑PD‑1 antibody (2 µg per dose). Tumor volumes are presented as the mean ± SD from biologically independent experiments (n = 7); p-values were calculated using a two-tailed unpaired t-test. NS non-significant; *p < 0.05; **p < 0.01; ***p < 0.001. Source data including exact p-values are provided as Source Data file.
