Figure 3.

Acute metformin exposure does not impact tumor growth. Mice were inoculated subcutaneously with 1×10⁶ mEER cells. Tumor-bearing 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). (A) Tumor volume was measured throughout the treatment period in all three treatment arms; no difference was noted between the arms (Tukey’s multiple comparison test; n=9–10 mice/group, n=2 experiments, *p<0.05; **p<0.01; ***p<0.001). (B) Flow cytometry was used to characterize T-cell and myeloid cell subsets in blood at the end of the experimental period. G-MDSCs, granulocytic myeloid derived suppressor cells; i.p, intraperitoneally; PBS, phosphate buffered-saline; Tregs, regulatory T cell.