The glucocorticoid receptor mediates a survival signal in human mammary epithelial cells

• Published in: Cancer research (Chicago, Ill.) Vol. 60; no. 4; pp. 867 - 872
• Main Authors: MORAN, T. J, GRAY, S, MIKOSZ, C. A, CONZEN, S. D
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 15-02-2000
• Subjects: Apoptosis; Arabidopsis Proteins; Biological and medical sciences; Breast - cytology; Cell physiology; Cell Survival; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Epithelial Cells - physiology; fas Receptor - physiology; Fatty Acid Desaturases - analysis; Female; Fundamental and applied biological sciences. Psychology; Humans; Mifepristone - pharmacology; Molecular and cellular biology; Phosphatidylinositol 3-Kinases - physiology; Phosphorylation; Protein-Serine-Threonine Kinases; Proto-Oncogene Proteins - physiology; Proto-Oncogene Proteins c-akt; Receptors, Glucocorticoid - physiology; Tumor Cells, Cultured; Human; Cell proliferation; Steroid hormone; Hydrocortisone; Glucocorticoid; In vitro; C-Onc gene; Adrenal hormone; Established cell line; Epithelial cell; Mammary gland; Mechanism of action; Apoptosis; Biological receptor
• ISSN: 0008-5472; 1538-7445

Complex autocrine and paracrine signaling pathways control the multiple cycles of epithelial cell proliferation and involution characteristic of the human mammary gland. Activation of these pathways can lead to cell division, cell cycle arrest, apoptosis, or survival; their aberrant regulation often contributes to malignant transformation. In this report, we show that glucocorticoid signals a potent survival pathway in the immortalized human mammary epithelial cell line MCF10A. Withdrawal of glucocorticoid from defined media triggers apoptosis, despite the presence of epidermal growth factor and insulin. Apoptosis is accelerated by ectopic expression of c-Myc and blocked by overexpression of Bcl2. Although MCF10A cells can undergo apoptosis after CD95/Fas receptor activation, cell death caused by glucocorticoid withdrawal is independent of CD95/ Fas receptor signaling. The mechanism through which glucocorticoid inhibits apoptosis is also independent of phosphatidylinositol 3-kinase activity and its downstream target Akt, thus establishing the existence of a novel epithelial cell survival pathway mediated by glucocorticoids.