Carcinogen-induced phenotypic alterations in mammary epithelial cells accompanying the development of neoplastic transformation.
Epithelial cells isolated from the mammary glands of virgin Sprague-Dawley rats and treated with 7,12-dimethylbenz[a] anthracene (DMBA) acquire an indefinite life span and anchorage-independent (AI) growth and form carcinomas in athymic nu/nu mice. Epithelial cells separated from fibroblasts and lipocytes by density-gradient centrifugation after collagenase digestion of the fat pads are grown in a hormone-supplemented medium. Control mammary epithelial cells survived approximately 30 days. After 2 days in culture, the mammary epithelial cells were treated with DMBA (1 microM) for 24 hr allowing for maximum oxidative metabolism of the hydrocarbon. DMBA-treated cells acquired an extended life span and grew in AI medium; however, in most cases, they were nontumorigenic and eventually ceased dividing. A pool of mammary epithelial cells, ME 10CL1, treated with DMBA has grown indefinitely, exhibited AI growth, and after 195 days in culture formed adenocarcinomas when 5 X 10(6) cells were injected into athymic nu/nu mice. When the tumor promoter, 12-O-tetra-decanoylphorbol-13-acetate (100 ng/ml), was added to another pool (ME 11CL2) of DMBA-treated mammary epithelial cells which had been in culture for 110 days, an irreversible increase in cell growth rate and a significant morphological alteration resulted. The 12-O-tetradecanoylphorbol-13-acetate-treated cells also formed colonies in AI medium after 140 days and poorly differentiated carcinomas in athymic nu/nu mice. Inhibition of tumor cell proliferation by tamoxifen is consistent with the mammary origin of the epithelial cells and suggests the presence of a viable estrogen receptor. The results demonstrate in vitro neoplastic transformation of rat mammary epithelial cells by DMBA or promotion of DMBA-initiated cells by 12-O-tetradecanoylphorbol-13-acetate resulting in two different epithelial tumor cell lines.
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000494:pharmacology; D000818:Animals; D002273:Carcinogens / Q000494:pharmacology*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D004848:Epithelium / Q000473:pathology; D005260:Female; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000473:pathology*; D010641:Phenotype; D051381:Rats; D011919:Rats, Inbred Strains; D013629:Tamoxifen / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D002273:Carcinogens; D013629:Tamoxifen; D015127:9,10-Dimethyl-1,2-benzanthracene; D013755:Tetradecanoylphorbol Acetate