title: Melatonin down-regulates hTERT expression induced by either natural estrogens (17beta-estradiol) or metalloestrogens (cadmium) in MCF-7 human breast cancer cells.
abstract: The goal was to evaluate whether melatonin (Mel) down-regulates hTERT expression induced by 17beta-estradiol (E(2)) or cadmium (Cd) in breast cancer cells. We found that: (a) Mel inhibits E(2) or Cd-induced hTERT transcription in hTERT-Luc transfected MCF-7 cells, (b) Mel significantly reduces E(2)- and Cd-mediated hTERT transactivation triggered by ERalpha in transfected HeLa cells, (c) Mel inhibits hTERT expression induced by E(2) or Cd in MCF-7 cells. Melatonin inhibition of telomerase activity supports a possible role in treatment of estrogen-dependent tumors or carcinogenesis by environmental or occupational exposure to xenoestrogens.
authors.affiliation: Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Cardenal Herrera Oria s/n, Santander, Spain.
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Martínez-Campa
authors.forename: Carolina
authors.initials: C
authors.lastname: Alonso-González
authors.forename: Maria D
authors.initials: MD
authors.lastname: Mediavilla
authors.forename: Samuel
authors.initials: S
authors.lastname: Cos
authors.forename: Alicia
authors.initials: A
authors.lastname: González
authors.forename: Emilio J
authors.initials: EJ
authors.lastname: Sanchez-Barcelo
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D002104:Cadmium / Q000494:pharmacology*; D045744:Cell Line, Tumor; D015536:Down-Regulation; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000502:physiology; D047629:Estrogen Receptor beta / Q000502:physiology; D006801:Humans; D008550:Melatonin / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D019098:Telomerase / Q000037:antagonists & inhibitors* / Q000235:genetics
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D012333:RNA, Messenger; D002104:Cadmium; D004958:Estradiol; C509186:TERT protein, human; D019098:Telomerase; D008550:Melatonin