title: Enhanced production of tissue-type plasminogen activator by estradiol in a novel type variant of human breast cancer MCF-7 cell line.
abstract: ES-1 cells, which showed a higher sensitivity to the cytocidal action of estradiol were isolated from a human breast cancer MCF-7 cell line. Growth of ES-1 cells was inhibited by a dose of 17-beta estradiol that stimulated the growth of the parental MCF-7 cells. Proteins secreted from MCF-7 and ES-1 cells when cultured with 17-beta estradiol were compared by sodium dodecyl sulfate-containing polyacrylamide gel electrophoresis (SDS-PAGE). Addition of estradiol to culture medium enhanced secretion of a protein of molecular mass of 52 kDa in media for both MCF-7 and ES-1 cell lines, but the secretion of a second 67 kDa protein was enhanced about 10-fold only in ES-1 cells. The analysis by SDS-PAGE of culture medium immunoprecipitated with anti-tissue-type plasminogen activator (t-PA) antibody demonstrated that the band of 67 kDa protein specifically secreted from estradiol-treated ES-1 cells contained t-PA. Zymography assays, quantitative immunoreactive assays, and Northern analysis showed about 5-fold specific increase by estradiol of t-PA with molecular mass of 65-70 kDa in ES-1 but not in its parental MCF-7 cells. Cellular level of the plasminogen activity was also specifically enhanced in ES-1 cells by estradiol, but only a slightly in MCF-7 cells. By contrast, another urokinase-type PA (u-PA) with molecular weight of 55 kDa showed very low level activity in both MCF-7 and ES-1 cell lines in the presence of estradiol. Formation of t-PA mRNA was specifically enhanced in ES-1 cells when ES-1 cells were treated for more than 12 h with 10(-8) M 17-beta estradiol. Estradiol did not elongate the lifetime of t-PA mRNA in ES-1 cells. A unique phenotype of ES-1 cells in response to estradiol is discussed in relation to activating expression of the t-PA gene.
authors.affiliation: Department of Biochemistry, Oita Medical School, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Mizoguchi
authors.forename: T
authors.initials: T
authors.lastname: Uchiumi
authors.forename: M
authors.initials: M
authors.lastname: Ono
authors.forename: K
authors.initials: K
authors.lastname: Kohno
authors.forename: M
authors.initials: M
authors.lastname: Kuwano
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D014644:Genetic Variation; D006801:Humans; D007700:Kinetics; D012333:RNA, Messenger / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000096:biosynthesis* / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D012333:RNA, Messenger; D004958:Estradiol; D010959:Tissue Plasminogen Activator