Johnson M L, Levy J, Rosen J M
In Vitro Cell Dev Biol. 1985 Aug;21(8):439-44. doi: 10.1007/BF02620831.
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 Subsequent addition of prolactin to the withdrawn cells caused a rapid accumulation of these mRNAs to prewithdrawal levels.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.
在附着于胶原凝胶上生长的、酪蛋白产生量增加或减少的7,12-二甲基苯并(a)蒽诱导的大鼠乳腺癌细胞亚群中，研究了乳蛋白基因表达。在含有10%胎牛血清、胰岛素（5微克/毫升）、氢化可的松（10微克/毫升）和催乳素（5微克/毫升）的条件下培养这些细胞，可使α-、β-和γ-酪蛋白以及乳清酸性蛋白mRNA的水平维持在与从奋乃静处理的大鼠中分离出的细胞相同的水平。相对于14天哺乳期乳腺，肿瘤细胞中乳清酸性蛋白mRNA的水平高于酪蛋白mRNA。从产生酪蛋白的细胞中去除催乳素会导致所有四种乳蛋白mRNA的丢失。随后向去除催乳素的细胞中添加催乳素会使这些mRNA迅速积累至去除前的水平。当这些肿瘤细胞在附着的胶原凝胶上培养时，该肿瘤细胞亚群中的乳蛋白基因表达受到催乳素（在胰岛素和氢化可的松存在的情况下）的调节，其方式与在正常乳腺中观察到的相似。
