title: Effect of estrogen on telomerase activity in human breast cancer cells.
abstract: To investigate the effects of estrogen (E2) on telomerase activity and its mechanism in human breast cancer cells, estrogen receptor positive MCF-7 cells were treated with different concentrations of E2. Telomerase activity was measured by using TRAP-ELISA method, the cell cycle phases analyzed by using flow cytometry, and the expression of Cyclin D1 detected by using immunohistochemistry method. The results showed that telomerase activity levels were increased in MCF-7 cells treated with 10(-8) mol/L E2 during the observed period (P < 0.05), and E2 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 E2 were changed significantly: G0/G1 phase decreased from 60.52% to 50.93%. S phase increased from 29.03% to 30.83%; However, the expression of Cyclin D1 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.
authors.affiliation: Department of General Surgery, Xiehe Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022.
authors.forename: Jinbo
authors.initials: J
authors.lastname: Gao
authors.forename: Daoda
authors.initials: D
authors.lastname: Chen
authors.forename: Yuan
authors.initials: Y
authors.lastname: Tian
authors.forename: Jinhui
authors.initials: J
authors.lastname: Zhang
authors.forename: Kailin
authors.initials: K
authors.lastname: Cai
mesh_terms: D001943:Breast Neoplasms / Q000737:chemistry / Q000201:enzymology* / Q000473:pathology; D002453:Cell Cycle; D019938:Cyclin D1 / Q000032:analysis; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006801:Humans; D011960:Receptors, Estrogen / Q000032:analysis; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D004967:Estrogens; D011960:Receptors, Estrogen; D019938:Cyclin D1; D019098:Telomerase