title: Maintenance of milk protein gene expression in a subpopulation of 7,12-dimethylbenz(a)anthracene-induced rat mammary carcinoma cells grown on attached collagen gels.
abstract: Milk protein gene expression was studied in cell subpopulations of 7,12-dimethylbenz(a)anthracene-induced rat mammary carcinoma cells enriched or depleted for casein production grown on attached collagen gels. Culture of these cells in the presence of 10% fetal bovine serum, insulin (5 micrograms/ml), hydrocortisone (10 micrograms/ml), and prolactin (5 micrograms/ml) maintained alpha-, beta-, and gamma-casein and whey acidic protein mRNAs at levels identical to cells isolated from perphenazine-treated rats. Whey acidic protein mRNA levels in the tumor cells relative to the 14-d lactating gland were greater than those of the casein mRNAs. Withdrawal of prolactin from the casein-producing cells resulted in the loss of all four milk protein mRNAs. Subsequent addition of prolactin to the withdrawn cells caused a rapid accumulation of these mRNAs to prewithdrawal levels. Milk protein gene expression in this tumor cell subpopulation is modulated by prolactin (in the presence of insulin and hydrocortisone) in a similar manner to that observed in the normal mammary gland when these tumor cells are cultured on attached collagen gels.
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D002364:Caseins / Q000096:biosynthesis / Q000235:genetics*; D002478:Cells, Cultured; D005260:Female; D005786:Gene Expression Regulation; D006207:Half-Life; D006854:Hydrocortisone / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007774:Lactation; D008321:Mammary Glands, Animal / Q000378:metabolism; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism; D008894:Milk Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D009924:Organ Culture Techniques; D011247:Pregnancy; D011388:Prolactin / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014158:Transcription, Genetic
chemical_list: D002364:Caseins; D007328:Insulin; D008894:Milk Proteins; D012333:RNA, Messenger; C024471:whey acidic proteins; D015127:9,10-Dimethyl-1,2-benzanthracene; D011388:Prolactin; D006854:Hydrocortisone