Induction of bcl-x(L) expression in mammary epithelial cells is glucocorticoid-dependent but not signal transducer and activator of transcription 5-dependent

In the present study, we examined the role of prolactin and glucocorticoids in regulating bcl-x transcription in mammary epithelial cells. We report t hat dexamethasone, but not prolactin, induced native bcl-x gene expression in a dose-dependent manner in HC11 cells and enhanced serum-starved HC11 ce ll survival, This effect was mediated through the glucocorticoid receptor a nd independent of STAT-5 activity. We propose that the mechanism through wh ich glucocorticoids enhance mammary epithelial cell survival is by increasi ng steady-state levels of bcl-x, RNA.