Fig 2: Autophagy, B7H3 expression, and CD8+T cells infiltration profile in breast cancer. Representative images of CD8+ T cell infiltrated areas (A), B7H3 expression (B) and LC3-II dots (C) by IHC in breast cancer tissue. Scale bar, 50 µm . D, the relationship between B7H3 expression and CD8+T cell infiltration percentage. E, the relationship between autophagy and B7H3 expression. Tumor samples were obtained from 65 patients with invasive breast carcinoma at the Sixth Affiliated Hospital, and data were presented as means ± SD; *p < 0.05 by Mann–Whitney U test. B7H3, B7 homolog 3; IHC, immunohistochemistry.

Fig 3: An overview schematic demonstrating that V9302 enhanced CD8+T cell activation by promoting B7H3 degradation via autophagy–lysosome pathway and potentiated the antitumor effect of anti-PD-1 immune therapy.

Fig 4: The degradation of B7H3 mainly depends on the autophagy–lysosomal pathway.A, Western blot showing LC3-II, a marker of autophagy, and B7H3 expression in different breast cancer cell lines. B, immunofluorescence detection of LC3-II/LAMP1 and B7H3 in different breast cancer cell lines which showing B7H3 was enriched within autophagosomes and lysosomes. Scale bar, 25 µm. C, Western blot showing LC3-II and B7H3 expression in MCF-7 and BT-474 treated with or without 150 nM Baf A1 for 6 h, an inhibitor of lysosome. D, flow cytometry analysis showing B7H3 expression in MCF-7 and BT-474 treated with or without Baf A1. E and F, flow cytometry analysis showing the proportion of Granzyme B (GZB)+CD8+T cells (E) and CD69+CD8+T cells (F). The left showed the representative flow cytometry images, and right showed the statistical columns. All experiments were performed three times independently. For D–F, data were presented as means ± SD, *p < 0.05, **p < 0.01 by Student’s t test. B7H3, B7 homolog 3.

Fig 5: PD-L1, ICOSLG, and B7-H3 are the direct target genes of miR-326.A Software (miRBase, PicTar, and TargetScan) prediction of the miR-326-targeted genes. B–D 293T cells were transfected with luciferase reporter plasmid containing PD-L1/B7-H3/ICOSLG wild-type or mutant-type 3' UTR and miR-NC (n = 3). E Schematic diagram of the binding sites between miR-326 and the target genes (PD-L1, B7-H3, and ICOSLG) and their mutant sequence. All data were presented as mean ± SEM. Comparisons between groups for statistical significance were performed with two-way ANOVA with Tukey’s post hoc test (B–D). ***P < 0.001 versus 3' UTR + miR-NC. ###P < 0.001 versus 3' UTR + miR-326.