Fig. 4 |. MUSIC activates STING mediated anti-tumour immunity.

a-g, WT and STING^−/− mice were inoculated with EO771 breast tumours, and treated with MUSIC, cGAMP, or cMBs (+US) following the strategy in Supplementary Fig. 17a. a, Representative photographs of mice at 24 days post tumour inoculation. b,c,e, Tumour volumes were monitored and analysed over the indicated periods. d,f, Survival curves for the mice in the different treatment groups. g, The six living tumour-free (TF) mice from the above MUSIC-treated group (b,d) were rechallenged with EO771 cells. Tumour volumes were measured over the following 28 days. n=10 for all WT mice, n=7 (PBS) or 8 (MUSIC) for STING^−/− mice (a,b,d-f), n=6 for ncMBs and n=7 for both MUSIC and IgG-ncMBs (+US) (c). a-g, n means biologically independent animals. h,i, Splenic T cells from mice treated 18 days post tumour inoculation were assessed by ELISPOT to further verify immune memory enhancement upon MUSIC treatment. n=3 biologically independent samples. j, IFN-γ and PD-L1 protein expression levels were detected by immunostaining in tumour paraffin section slides. Representative images from random fields of view from one of three biologically independent animals. Scale bar=50 μm. k, Quantification and comparison of fluorescence intensity using ImageJ software from three randomly selected images of 3 biologically independent mice. The data represent mean ± s.e.m. (b,c,e,g) or mean ± s.d. (i,k), analysed by two-sided log-rank (Mantel-Cox) test (d,f), or one-way ANOVA with Tukey’s multiple comparisons test (b,c,e,g,i,k). *P and ^#P in (b,d) denote the statistical significance relative to the MUSIC group, respectively.