Vol. 285, Issue 2, 876-883, May 1998

Dehydroepiandrosterone and Analogs Inhibit DNA Binding of AP-1 and Airway Smooth Muscle Proliferation¹

Rustom Dashtaki, A. Richard Whorton, Thomas M. Murphy, Pasquale Chitano, William Reed and Thomas P. Kennedy

Department of Internal Medicine (R.D., T.P.K.), Carolinas Medical Center, Charlotte, North Carolina; the Departments of Pediatrics (T.M.M., P.C.) and Pharmacology (A.R.W.), Duke University, Durham, North Carolina and the Center for Environmental Medicine and Lung Biology (W.R.), University of North Carolina, Chapel Hill, North Carolina

The adrenal steroid dehydroepiandrosterone (DHEA) and its analogs reduce growth of immortalized and malignant cell lines. We therefore explored their effects on the growth of airway smooth muscle, whose hyperplasia may lead to fixed airways obstruction and enhanced airways hyperresponsiveness in severe chronic asthma. DHEA and its potent analog 16-bromoepiandrosterone dramatically reduced proliferation in primary cultures of rat tracheal smooth muscle stimulated with fetal bovine serum or platelet-derived growth factor. Growth inhibition was dose-dependent and could not be attributed to interference with glucose-6-phosphate dehydrogenase activity or cholesterol metabolism, as reported for immortalized or malignant cell lines, respectively. Expression of the early response gene c-fos remained intact, but DHEA and 16-bromoepiandrosterone decreased DNA binding of the transcription factor activator protein-1, a later response important for expression of genes that mediate DNA synthesis and cell cycle progression. These results suggest that the nonglucocorticoid steroid DHEA and its analogs may impair activation of secondary growth response genes in a fashion analogous to that reported for glucocorticoids and that they may prove useful for treatment of asthmatic airway remodeling in the human.