Fig 2: The combination of USP8 inhibitor with PD-1/PD-L1 blockade significantly suppresses tumor growth in vivo.a, b Tumor growth or Kaplan–Meier survival curves for C57BL/6 bearing MC38 tumors with indicated treatments. n = 7 mice/group. log-rank test (b). mAb: monoclonal antibody. c, d Tumor growth or Kaplan–Meier survival curves for BALB/c mice bearing CT26 tumors with indicated treatments. n = 9 (control), 7 (DUBs-IN-2), 6 (PD-L1 mAb), 7 (PD-1 mAb), 8 (PD-1 mAb plus DUBs-IN-2) or 7 (PD-L1 mAb plus DUBs-IN-2) mice. log-rank test (d). e–g Representative images of HE staining (e), tumor sizes (f), or tumor areas (g) in tumor-burdened lungs of KP mice were analyzed. Scale bars represent 5 mm. n = 5, 6, 5, or 4 mice/group. h Quantification of CD8+ T cells represented as percentage of tumor-infiltrating lymphocytes (TIL) in CT26 tumors after indicated treatments. n = 6, 5, 5, or 5 mice/group. i, j Quantification of Granzyme B (GzmB) (i) or TIM3 (j) represented as percentage on CD8+ TILs in CT26 tumors after indicated treatments. n = 5, 5, 5, or 4 mice/group. k Tumor growth of sgControl or sgUsp8 CT26 cells in BALB/c mice with indicated treatments. n = 5 mice/group. l Quantification of CD8+ T cells represented as percentage of TIL in sgControl or sgUsp8 CT26 tumors after indicated treatments. n = 5 mice/group. m Quantification of GzmB represented as percentage on tumor-infiltrating CD8+ T cells in sgControl or sgUsp8 CT26 tumors after indicated treatments. n = 5 mice/group. n A working model for targeting USP8 sensitizes tumors to PD-1/PD-L1 blockade. USP8 downregulates PD-L1 and MHC-I-mediated antigen-presenting, leading to non-inflamed TME and resistance to PD-1/PD-L1 blockade (left panel). However, inhibition of USP8 by DUBs-IN-2 upregulates PD-L1 and antigen-presenting, setting up an inflamed TME and sensitive to anti-PD-1/PD-L1 immunotherapy (right panel). Ub: ubiquitin. TME: tumor microenvironment. For a, c, k data were presented as mean ± S.D.; two-way ANOVA test. For f, g, h–j, l, m data were presented as mean ± S.D.; two-sided t-test. Source data are provided as a Source Data file.

Fig 3: Tracking tumor-immune interactions in tumors from transplanted antigen-expressing organoids. (A) Bright-field (top) and fluorescent (bottom) images of representative KPSIIN tumors across tumor progression. (B) Hematoxylin and eosin (H&E) (top) and immunohistochemical staining for mScarlet (bottom) in KPSIIN organoid-derived tumors. (C) Quantification of KPSIIN tumor penetrance at each time point. (D) Quantification of the percent of antigen-specific CD8 T cells in the lung CD8 T cell infiltrate. N = 4 per time point. (E) Flow cytometry quantification of TIM3- and PD1-expressing CD8 T cells in the lung, antigen-specific CD8 T cell infiltrate. N = 4 per time point.