Figure 4. Metformin inhibits the binding probability but not binding force of TGF-β1 and TβRII.
TGF-β1–TβRII binding force measurements were obtained with TGF-β1-modified atomic force microscopy (AFM) tips on HeLa cells, which express TβRII. Blocking experiments were performed by the addition of free TGF-β1 monoclonal antibodies into the solution. (a) Histograms of binding forces of TGF-β1/TβRII in the untreated cells and (b) the cells treated with 50 μM metformin. (c) Binding forces of TGF-β1/TβRII in cells treated with/without 50 μM metformin. (d) Binding probability of TGF-β1and TβRII when the cells were treated with metformin and/or the blocking reagent (anti-TGF-β1 antibody). Data were expressed as the mean ± SEM from 3 independent experiments. Mann-Whitney U test (one tailed) with exact method was used. *P < 0.05.