title: Glucocorticoid and mineralocorticoid cross-talk with progesterone receptor to induce focal adhesion and growth inhibition in breast cancer cells.
abstract: Progesterone receptor (PR), glucocorticoid receptor, and mineralocorticoid receptor belong to a subfamily of nuclear receptor superfamily with similar sequence and structural characteristics. Many reports have documented glucocorticoid-like effects of progesterone in various tissues. This study addresses the issue of cross-talk between corticosteroids and PR using PR-transfected MDA-MB-231 cells ABC28 and vector-transfected control cells CTC15. At physiological concentrations, dexamethasone, cortisol, and aldosterone mimic the effects of progesterone by inducing significant growth inhibition, cell spreading, and focal adhesions in PR-positive ABC28 cells. These hormones also induce progesterone-like effects in increasing the expression of p21(CIP1/WAF1) protein and decreasing the level of phospho-p42/p44 mAPK. Two lines of evidence suggest that these effects are mediated by cross-talk with PR. First, these compounds do not exhibit the same progesterone-like effects in PR-negative CTC15 cells. Second, PR blocker ZK98299 abolishes their effect on cell spreading and focal adhesion in ABC28 cells. The cross-talk is corticosteroid specific because estradiol and thyroid hormone triiodothyronine have no effect on PR-transfected cells ABC28. It is also interesting to note that dexamethasone induces a small but detectable increase of focal adhesions and limited growth stimulation in vector-transfected cells CTC15. In contrast, progesterone exhibits no detectable effect on CTC15 cells. This study provides evidence that glucocorticoid and mineralocorticoid cross-talk with PR to produce progesterone-like effects in breast cancer cells. Glucocorticoid receptor and PR share some overlapping activity in mediating focal adhesion but not in regulating cell proliferation.
authors: Department of Clinical Research, Singapore General Hospital, 637616.
authors: Joyce C L
authors: JC
authors: Leo
authors: Chunhua
authors: C
authors: Guo
authors: Chow Thai
authors: CT
authors: Woon
authors: Swee Eng
authors: SE
authors: Aw
authors: Valerie C L
authors: VC
authors: Lin
mesh_terms: D000450:Aldosterone / Q000494:pharmacology; D001943:Breast Neoplasms; D002455:Cell Division / Q000502:physiology; D045744:Cell Line, Tumor / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D022001:Focal Adhesions / Q000502:physiology; D015870:Gene Expression / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology; D020239:Receptor Cross-Talk / Q000502:physiology; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*; D018161:Receptors, Mineralocorticoid / Q000235:genetics / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D014162:Transfection
chemical_list: D005938:Glucocorticoids; D011965:Receptors, Glucocorticoid; D018161:Receptors, Mineralocorticoid; D011980:Receptors, Progesterone; D000450:Aldosterone; D011374:Progesterone; D003907:Dexamethasone; D006854:Hydrocortisone