Effects of Three Kinds of Tea Extracts on Proliferation and Apoptosis of MCF-7 Cells and Their Relationship to Protein Kinase B

Objective To investigate the effects of extracts from Black Tea,Green Tea and Pu-erh Tea on the proliferation and apoptosis of human breast cancer MCF-7 cells as well as their relationship to protein kinase B(PKB).Methods MCF-7 cells were treated with the three kinds of tea extracts at various concentrations for various hours,then determined for proliferation level by MTT method,for apoptosis level by flow cytometry with Annexin V-FITC / PI staining,and for transcription level of PKB mRNA by realtime fluorescent quantitative PCR.Results All the three kinds of tea extracts showed significantly inhibitory effect on the proliferation of MCF-7 cells,in time-and dosage-dependent modes.The apoptosis rates at early stage of cells treated with the tea extracts were higher than those untreated.The expression level of PKB mRNA in the cells treated with tea extracts decreased significantly as compared with those in the cells untreated.Conclusion All the three kinds of tea extracts contained the natural components inhibiting the transcription activity of PKB and induced the apoptosis of MCF-7 cells,among which Green Tea extracts induced effectively as compared with the other two extracts.