Figure 4. ATXN3 inhibition improves antitumor immunity partially through downregulating tumoral PD-L1 expression.

(A–C) WT or ATXN3-KO LLC1 cells were injected subcutaneously into C57BL/6 mice (n = 10). Tumor growth curve (A), photograph (B), and weight (C) are shown. (D) MFI of surface PD-L1 on LLC1 tumors (n = 5). (E–G) Quantification of CD4⁺ (E) and CD8⁺ T cell (F) and Treg (G) percentages (n = 5–10). (H and I) Quantification of cell-surface PD-1 (H) and PD-L1 (I) MFI on CD8⁺ T cells (n = 5). (J and K) Quantification of cell-surface CTLA-4 MFI (J) and Tim3 percentage (K) in CD8⁺ T cells (n = 5). (L) MFI of cell-surface LAG3 and percentage in CD8⁺ T cells (n = 5). (M–O) Intracellular staining of Blimp1⁺ CD8⁺ T cell (M), EOMES⁺ CD8⁺ T cell (N), and T-bet⁺ CD8⁺ T cell (O) percentage in LLC1 tumors (n = 5-7). (P) Quantification of cell-surface CD44⁺ CD8⁺ T cell percentage from LLC1 tumors (n = 5–10). (Q) Apoptotic CD8⁺ T cells in the tumors were analyzed (n = 5–7). (R and S) Representative flow staining and quantification of intracellular cytokine staining of granzyme B⁺CD8⁺ and IFN-γ⁺CD8⁺ in CD45⁺ T cell populations from LLC1 tumors (n = 5). (T) Tumor growth curve and tumor photograph of C57BL/6 mice injected subcutaneously with WT and ATXN3-KO LLC1 cells with or without treatment of anti-CD8 depleting antibodies (n = 5). (U) Left: Tumor cell-surface PD-L1 expression. Right: Tumor growth of WT or ATXN3-KO LLC1 cells stably expressing PD-L1 (as shown in the left plot) in C57BL/6 mice (n = 5). A and C–S: 2-tailed unpaired t test; T and U: ordinary 1-way ANOVA. *P < 0.05, **P < 0.01,***P < 0.001.