Endocrine Abstracts

Introduction: Glucocorticoids (GCs) are closely related to cortisol and the dysregulation of its secretion can lead to the onset of disorders. Cushing’s syndrome (CS) is the clinical manifestation of hypercortisolism and can also develop in subjects who voluntarily or accidentally take high GCs doses. The aim of this study is to conduct preliminary investigations to characterize the HEK293 cell line, to evaluate its response to GCs and to compounds with GC-like activity.

Methods: Cells were incubated for 48H and 72H with different Dexamethasone concentrations ([Dex]) (phase 1: 1-100 mM; and phase 2: 0,25-5 mM) and cell proliferation rate was assessed by cell counting, compared to untreated cells (C). To confirm specificity, incubations with Mifepristone ([Mif]), a GCs antagonist binding GR catalytic site, were also performed. Data analysis was performed using a two-sample independent t-test. A P-value ≤ 0,05 was considered significant. Results: The results show that HEK293 cells in phase 1 had significant cell mortality rate (48H: 1 mM (42%), 5 mM (70%), 10 mM (76%), 50 mM (74%), 100 mM (78%); 72H: 5 mM (83%), 10 mM (82%), 50 mM (91%), 100 mM (89%)); in phase 2 cell mortality rate were slightly lower (48H: 1 mM (37%), 2,5 mM (36%), 5 mM (47%); 72H: 0,25 mM (37%), 0,5 mM (56%), 1 mM (49%), 2,5 mM (59%), 5 mM (71%)). The EC50-Dex were: 3,3 mM (48H) and 0,70 mM (72H). Cells were also incubated with increasing ([Mif]) w/o EC50-Dex to test specificity. The minimum [Mif] that blocked the antiproliferative effects of Dex were 50 mM (48H: 52%) and 0,70 mM (72H: 160%).

Conclusion: This cellular model seems to be a valid in vitro model for the evaluation of GCs or GCs-like activity. The latter may be present in substances or products that are used daily and therefore difficult to detect.