Fig. 6

CEBPD/VAMP3 affects the cytotoxicity of CD8⁺ T cells to the PTX-resistant TNBC cells. EVs derived from differentially treated (sh-NC, sh-CEBPD, sh-CEBPD + oe-NC, and sh-CEBPD + oe-VAMP3) PTX-resistant cells were collected, which were co-cultured with activated CD8⁺ T cells for 48 h. A, concentrations of IFN-γ, Granzyme B, and Perforin in the supernatant of co-culture system examined using ELISA kits (n = 3); B, proportion of exhausted CD8⁺ T cells (Tim3⁺CD8⁺) analyzed by flow cytometry (n = 3). Differentially treated MDA-MB-231/PTX cells were injected into C57BL/6 J mice. When the tumor volume reached 100 mm³, PTX treatment was applied at 20 mg/kg via intraperitoneal injection twice a week. C, growth rate of xenograft tumors in mice (n = 5); D, weight of xenograft tumors on day 28 (n = 5); E, proportion of exhausted CD8⁺ T cells (Tim3⁺CD8.⁺) in the tumor-infiltrating lymphocytes analyzed by flow cytometry (n = 5). Differences were analyzed by the one-way (D-E) or two-way (A-C) ANOVA with Tukey's post-hoc test (B, D). *p < 0.05