Figure 4.

Chronic metformin exposure delays tumor growth. Mice were treated with PBS, metformin delivered intraperitoneally (40 mg/kg; 5 days/week) or metformin solubilized in drinking water (0.5 mg/100 mL) for 4 weeks prior to subcutaneous inoculation with 1×10⁶ female mEER cells (left flank). Treatment continued until the end of the study. (A) Tumor volume was measured throughout the treatment period in all three treatment arms; differences in tumor volume were evaluated at time of first control mouse euthanasia (Tukey’s multiple comparison test; n=5–10 mice per group, n=2 experiments, *p<0.05; **p<0.01; ***p<0.001; ****p<0.0001). (B) Flow cytometry was used to characterize T-cell and myeloid cell subsets in blood at the end of the experimental period. DCs, dendritic cell; i.p, intraperitoneally; PBS, phosphate buffered-saline; Tregs, regulatory T cell.