Fig. 8. The anti-tumor immunity induced by the combination therapy depends on the PD-L1 pathway and CD8 + T cells.

a, b Western blotting and flow cytometry results validating Cd274 KO in KPC cell line. c Schematic of the protocol for USP8 inhibitor and αPD-L1 combination therapy for orthotopic KPC parental and Cd274 KO cell (5 ×10⁵)-bearing mice. d Photographs of tumors removed from mice of each group (n = 5). e The statistical plot of tumor weights of the four groups (n = 5). f The body weight of mice on the last day (n = 5). g Experimental design for CD8 + T cells depletion in orthotopic KPC (5 × 105)-bearing mice receiving the combination therapy. h Photographs of tumors removed from the mice in each group (n = 5). i The statistical plot of the tumor weights of the four groups (n = 5). j Changes in mouse body weight (n = 5). k, l Flow cytometry of CD8 + T cells of spleens and the statistical analysis of the results (n = 5). m The model shows the regulation of PD-L1 stability by USP8 in pancreatic cancer. USP8 inhibitor treatment downregulates PD-L1 protein levels via degradation, leading to activation of the cytotoxic T-cells. The results are displayed as the means ± SD from representative experiments in (e, f, i, j and l). The data represent three independent experiments. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 assessed via a two-tailed t test; ns not significant.