Fig. 6: Acetate supplementation overcomes chronic stress-promoted breast cancer progression by activating CD8⁺ T cells.

a Schematic representation of the experimental design. Mice were treated with sodium chloride (NaCl) or sodium acetate (NaAc) and then divided into two groups: one group was exposed to chronic restraint stress for 14 consecutive days before 4T1 cells inoculation and continued until the end of the experiment, and the other group was inoculated with 4T1 cells without stress exposure. The NaAc groups received NaAc throughout the experiment. Created with BioRender.com. b Tumor growth volume of mice treated with NaCl or NaAc and subjected to chronic restraint stress or not (Tumor group: n = 6, tumor + stress group: n = 6, tumor + NaAc group: n = 6, tumor + stress + NaAc group: n = 8). c Tumor weight and tumor burdens in the lungs of the mice (tumor group: n = 6, tumor + stress group: n = 6, tumor + NaAc group: n = 6, tumor + stress + NaAc group: n = 8). d Tumor-infiltrating CD8⁺ T cells with or without NaAc treatment in mice (n = 5 per group). e IFN-γ expression in the tumor-infiltrating CD8⁺ T cells by qPCR (n = 6 per group). f, g Tumor growth volume and tumor burdens in supplemental NaAc-stressed tumor mice with or without depletion of CD8⁺ T cells (n = 6 per group). h Tumor-infiltrating CD8⁺ T cells in mice after NaAc treatment with or without depletion of CD8⁺ T cells (n = 6 per group). Data were presented as mean ± SEM. Statistical significance was determined by two-way ANOVA followed by Sidak’s multiple comparisons test for (b, f), one-way ANOVA followed by Dunnett’s multiple comparisons test for (c–e, h), and unpaired two-tailed Student’s t-test for (g). Significance levels are denoted as *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001. “ns” means no significant difference. Source data and exact p values are provided in the Source data file.