Apoptosis of K562/ADM cells induced by mimics of MnSOD

Objective:To investigate the proliferation-inhibiting and apoptosis-inducing activity of mimics of manganese superoxide dismutase(MnSODm) on human multidrug-resistant leukemia cell line K562/ADM in vitro.Methods:Human multidrug-resistant leukemia cell line K562/ADM over-expressing mdr1 gene was used as the target cells.The cell proliferating activity was assessed with a MTT colorimetric assay.The morphology of K562/ADM cells was observed with optical,fluorescent and electronic microscopy,and apoptosis was explored by double staining of FITC-Annexin V and propidium iodide(PI).Results:MnSODm(1-50 mg/L) obviously inhibited the proliferation of K562/ADM cells in a manner depending on both dose and time(P0.01).The cells treated with MnSODm showed the typical apoptotic morphological changes.The apoptotic rate of MnSODm-treated K562/ADM cells assed with Annexin Ⅴ/PI staining was greatly increased from 3.32% to 13.91% and 55.0% after exposure to 10 mg/L and 50 mg/L for 48 hours.Conclusion:MnSODm greatly inhibits the proliferation of drug-resistant K562/ADM cells,and induces apoptosis of K562/ADM cells in vitro.