Fig. 2: EVs containing activated STING execute antitumor activity.

a Knockout efficiency of STING in 4T1 cells shown by western blot analysis. b–d BALB/c mice were implanted subcutaneously with mouse 4T1 tumor cells for a week followed by tail vein injection of PBS or 5 μg EVPs derived from 4T1 cells three times a week. The xenografts were excised (b); tumor volume was monitored three times a week, P values were calculated by two-way ANOVA (c). Tumor weight on day 19 after transplantation was shown, and P value was calculated by Student’s t-test (d). n = 6. The data were presented as means ± SEM. e, f FACS analysis showing the infiltration of both CD3⁺ and CD8⁺ T cells in BALB/c mice bearing subcutaneous 4T1 tumors. P values were calculated by Student’s t-test. g, h THP-1 cells were collected after 24-h exposure to EVPs harvested from conditioned media of wild-type and STING^−/− NCI-H1975 cells stimulated with 25 μM Ruc (g) or 8 Gy IR (h). The mRNA level of IFNβ was then quantified. P values were calculated by Student’s t-test. i Serum STING concentrations in NPC patients with different responses to chemoradiotherapy. P value was calculated by Student’s t-test. n = 26 for OR, and n = 14 for SD. OR, objective response; SD, stable disease.