Effect of Estrogen on Telomerase Activity in Human Breast Cancer Cells

摘要

To investigate the effects of estrogen ( E_2) on telomerase activity and its mechanism in human breast cancer cells, estrogen receptor positive MCF-7 cells were treated with different concentrations of E_2. Telomerase activity was measured by using TRAP-ELISA method, the cell cycle phases analyzed by using flow cytometry, and the expression of Cyclin D_1 detected by using immu-nohistochemistry method. The results showed that telomerase activity levels were increased in MCF-7 cells treated with 10~(-8) mol/L E_2 during the observed period (P<0. 05), and E_2 increased telomerase activity levels in a dose-dependent manner (10~(-10) - 10~(-8) mol/L); Simultaneously, the cell cycle phases of MCF-7 cells treated with 10~(-8) mol/L E_2 were changed significantly: G_0/G_1 phase decreased from 60. 52% to 50. 93% , S phase increased from 29. 03% to 30. 83%; However, the expression of Cyclin D_1 was decreased. It was concluded that estrogen can upregulate telomerase activity of MCF-7 cells, and the effect can be blocked by antiestrogen tamoxifen. Its mechanism may be closely associated with modulation of cell cycle phases.