Figure 2.
Combination of 3M‐052 with PD‐1 blockade decreases lung metastasis. (a) Experimental intervention timeline. BALB/c mice were injected with 1 × 105 4T1.2 cells into the 4th mammary fat pad, and palpable tumors were i.t. injected with vehicle or 3M‐052 on day 7 post‐inoculation. Mice were treated with four doses of isotype or anti‐PD1 mAb in a neoadjuvant setting before primary tumor resection on day 14. Primary tumors were assessed for (b) weight and (c) were assessed by IHC for Ki67, c‐caspase‐3 and PD1 expression (40× magnification, scale bars = 50 µm, representative images shown). (d) Day 21 bioluminescence imaging of the thoracic cavity and lungs. (e) Kaplan–Meier survival curve comparing metastasis‐free survival. Survival assay: n = 10 mice/group; and IHC: n = 3 mice/group. Experiments were independently repeated twice, and representative data are shown. Statistical analysis was performed by (b) one‐way ANOVA with post hoc Tukey's multiple comparison test and (e) the Mantel–Cox log‐rank test. Error bars are SEM. **P < 0.01; ***P < 0.001; and ****P < 0.0001.