Figure 6

SR9243 immunotherapeutic activity is CD8+ T-cell dependent. (A) Immunohistochemical staining showing CD8+ infiltration into E0771 tumors from SR9243 or vehicle control treated mice. (B) Average number of CD8+ T-cells quantified in vehicle versus SR9243 treated tumors (n = 6). The number of CD8+ cells were quantified using ImageJ. *p < 0.05 determined by student’s t-test. (C) FACs dot-plot showing the percentage of tumor resident CD8+ effector T-cells expressing PD-1 in vehicle and SR9243 treated mice (D) Average percentage of tumor-resident CD8+ effector T-cells expressing PD-1+ in vehicle versus SR9243 treated groups (n = 6). (E) FACs dot-plot showing the percentage of lymph-node resident CD8+ effector T-cells that are positive for PD-1 expression in vehicle and SR9243 treated mice (F) Average percentage of lymph-node resident CD8+ effector T-cells expressing PD-1+ in vehicle versus SR9243 treated groups (n = 6). (G) FACs dot-plot showing the percentage of lymph node resident CD8+ effector memory T-cells expressing GZMB in control or SR9243 treated mice. (H) Average percentage of GZMB expressing effector T-cells in the draining lymph-nodes of vehicle and SR9243 treated mice. (I) FACs dot-plot showing the percentage of lymph node resident CD8+ T-cells expressing GZMB in vehicle and SR9243 mice. (J) Mean percentage of lymph-node resident CD8+ T-cells expressing GZMB in vehicle and SR9243 treated mice (K) Individual E0771 tumor allograft volumes for individual mice receiving Rat IgG2A and dosed with vehicle or 60 mg/kg SR9243. (L) Mean tumor allograft volume for vehicle and SR9243 treated groups in J. (M) Individual E0771-allograft volumes for SR9243 and vehicle treated mice (N) Mean E0771-tumor allograft volumes for mice depleted of CD8 T-cells and treated with vehicle or SR9243 in K. For CD8+ T-cell depletion tumor bearing mice were dosed with αCD8 antibody (Bio-X-Cell) (or Rat IgG control) every three days for 9 days. Mice were then treated with 60 mg/kg SR9243 or vehicle once daily for 14 days (n = 10). *p < 0.05 ***p < 0.001 as determined by student’s t-test of 2-Way ANOVA.