Effects of zinc on apoptosis of prostate cancer cells

Objective To investigate the effects of zinc on apoptosis of prostate cancer cells(PC-3M). Methods The cell proliferation was determined by MTT assay treated with different concentrations of ZnSO_4·7H_2O (end concentrations were 6.25,15,25,50,100,150,200,250,and 300 μmol·L~ -1 ,respectively), the cell morphological changes after exposed to zinc for 24 h was observed under phase-contrast microscope, the apoptosis was detected by AO/EB assay, the cell cycle and apoptotic peak were detected by flow cytometry, DNA fragmentation was observed by agarose gel electrophoresis(AGE).Results PC-3M cells proliferation rate was obviously changed after exposed to different levels of zinc for 24 h. Zinc(250 μmol·L~ -1 ) inhibited proliferation of PC-3M cells (P0.01). Compared with control cells, the changes of morphological characteristics of PC-3M cells were found,including shrank and floated,decreased refraction in the cells exposed to zinc (250 μmol·L~ -1 ) for 24 h. The confocal microscopy showed the changes of cells through AO/EB staining.The cellular membrane was integrity but vacuolization of the cytoplasm,chromatin was flavo-green, nuclear condensed, nuclear side collection, caryolysis, nuclear fragmented. The flow cytometry showed the hypodip-loid peak in G_0/G_1 phase after exposed to zinc (250 μmol·L~ -1 )for 24 h. It had visible DNA fragmentation by AGE. Conclusion Zinc with high concentrationcan inhibit human prostate cancer cell growth and induce apoptosis of human prostate cancer cells.