Figure 6. Restoration of viral sensing increases interferon signaling and sensitizes Fbxw7-deficient tumors to anti-PD-1.
(a) Growth of control or Mavs-deficient D4C9 cells in C57BL/6 mice. Anti-PD-1 or control immunoglobulin were administered at days 9, 12, 15 (black arrowheads) after implantation (n ≥ 8 tumors per group). One-way ANOVA with Sidak’s multiple comparison test was used to determine statistical significance. ****, P<0.0001. (b) Western blot of control and Fbxw7-deficient D4C9 cells transduced with Egfp- or Mavs-expressing virus. (c, d) Relative (c) Cxcl10 or (d) Ifnb1 mRNA expression in control and Fbxw7-deficient D4C9 cells overexpressing Mavs or an empty vector. Each dot represents a biological replicate. RM one-way ANOVA with Sidak’s multiple comparison test was used to determine statistical significance *, P <0.05. (e-g) Expression of (e, f) MHC-I (H-2Db) and (e, g) Pd-L1 in control and Fbxw7-deficient D4C9 cells overexpressing Mavs or an empty vector. (e) One representative experiment is shown. (f, g) MFI (median fluorescent intensity) was measured relative to sgCtrl + EV (Empty Vector). Each dot represents a biological replicate. RM one-way ANOVA with Sidak’s multiple comparison test was used to determine statistical significance. ****, P <0.0001; **, P <0.01; *, P <0.05. (h) Growth of control and Fbxw7-deficient D4C9 cells transduced with Mavs cDNA or an empty vector, in C57BL/6 animals. Anti-PD-1 or control immunoglobulin were administered at days 9, 12, 15 (black arrowheads) after implantation (n ≥ 8 biologically independent samples per group). One-way ANOVA with Sidak’s multiple comparison test was used to determine statistical significance. ***, P<0.001, *, P <0.05. (i) Survival of C57BL/6 mice implanted with D4C9 derivatives (n = 5 per group). Significant differences between groups were calculated by Log-rank (Mantel-Cox) tests with Bonferroni correction. **, P < 0.01.