Induction of bcl-xL 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 that dexamethasone, but not prolactin, induced native bcl-x gene expression in a dose-dependent manner in HC11 cells and enhanced serum-starved HC11 cell survival. This effect was mediated through the glucocorticoid receptor and independent of STAT-5 activity. We propose that the mechanism through which glucocorticoids enhance mammary epithelial cell survival is by increasing steady-state levels of bcl-xL, RNA.