Fig. 3
Antitumor effect of combination therapy with hCHST15 siRNA and anti-PD-1 antibody in Pan02-implantation model. (A) Experimental design. Mouse Pan02 cells (3 × 106 cells/mouse) were implanted subcutaneously into syngeneic C57/BL6 mice on day 0. Four groups were conducted: (1) Control (Pan02 inoculation only) (n = 5), (2) hCHST15 siRNA monotherapy (1.0 mg/mouse) (n = 5), (3) anti-PD-1 antibody monotherapy (5 mg/kg/mouse) (n = 5), (4) Combination therapy of hCHST15 siRNA and anti-PD-1 antibody (n = 5). Local [Intratumoral] injections for saline or hCHST15 siRNA were performed BIW from day 28 to 38, × 3 times in total. Systemic injections for anti-PD-1 antibody of control antibody were performed BIW from day 28 to 38, × 4 times in total. (B) (left panels) The macroscopic images of the tumor in 4 groups at day 42. Scale bar = 10 mm. Dotted circles show the tumor area. Triangles indicate the margin of hemorrhagic tumor necrosis. (middle panel) Tumor volume (mm3) was calculated by macroscopically on day 42. (left panel) Macroscopic necrotic area (%) at day 42. CTL: Control (n = 5), siRNA: hCHST15 siRNA monotherapy (n = 5), aPD1: anti-PD-1 antibody monotherapy (n = 4), siRNA + aPD1: hCHST15 siRNA + aPD1 combination therapy (n = 5). One-way ANOVA Bonferroni’s multiple comparison test, *p < 0.05, ns: not significant, Welch’s t-test for CTL vs aPD1 + siRNA (middle), and aPD1 vs aPD1 + siRNA (right), #p < 0.05. TGI was calculated as follows; TGI (%) = (1-Ti/Vi) × 100. Ti as the mean tumor volume of the treatment group on day 42. Vi as the mean tumor volume of control group at day 42. (C) % CD3-positive (left panel) and CD19-positive (right panel) cells in tumor-infiltrating lymphocyte (TIL) at day 42. CTL: Control (n = 5), siRNA: hCHST15 siRNA monotherapy (n = 4), aPD1: anti-PD-1 antibody monotherapy (n = 4), siRNA + aPD1: hCHST15 siRNA + aPD1 combination therapy (n = 5). One-way ANOVA Bonferroni’s multiple comparison test, *p < 0.05, ns: not significant.
