Spermdine collapsed MMP in HeLa cells. Cells were treated with spermidine (0, 0.5, 1.0 mM) for 8 h or 50 μM CCCP for 3 h. MMP was measured by flow cytometry. Results are expressed as the percentage of control and represent the mean ± S.E.M. of three independent experiments. *p < 0.05, compared with control.