title: Differential regulation of c-myc by progestins and antiestrogens in T-47D human breast cancer cells.
abstract: In order to investigate further the mechanisms associated with growth inhibition of human breast cancer cells by progestins and nonsteroidal antiestrogens, their effect on c-myc gene expression in T-47D-5 and T-47D cells has been investigated. The c-myc mRNA levels were differentially regulated by the synthetic progestin, medroxyprogesterone acetate and the nonsteroidal antiestrogen, monohydroxytamoxifen, in both cell lines. Antiestrogen treatment caused a persistent decrease in c-myc mRNA levels while the progestin caused a more complex response. Initially c-myc mRNA levels increased approx. 2-fold, this was followed by a decrease and then partial recovery. The end result, however, of each of these treatments is decreased cell number.
authors.affiliation: Department of Biochemistry, University of Manitoba, Winnipeg, Canada.
authors.forename: M S
authors.initials: MS
authors.lastname: Wong
authors.forename: L C
authors.initials: LC
authors.lastname: Murphy
mesh_terms: D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000187:drug effects; D004965:Estrogen Antagonists / Q000494:pharmacology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D016259:Genes, myc; D006801:Humans; D008525:Medroxyprogesterone / Q000031:analogs & derivatives / Q000494:pharmacology; D017258:Medroxyprogesterone Acetate; D011372:Progestins / Q000494:pharmacology*; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D013629:Tamoxifen / Q000031:analogs & derivatives / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D004965:Estrogen Antagonists; D011372:Progestins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D013629:Tamoxifen; C016601:afimoxifene; D017258:Medroxyprogesterone Acetate; D008525:Medroxyprogesterone