Purpose: Glucocorticoids such as dexamethasone are widely used for medication of urological diseases, e.g., as cotreatment of advanced prostate cancer, to improve appetite, weight loss, fatigue, relieve bone pain, diminish ureteric obstruction, to reduce the production of adrenal androgens, as an antiemetic in patients undergoing chemo- and/or radiotherapy together with serving as "standard" therapy arm in randomized studies. While the potent pro-apoptotic properties and the supportive effects of glucocorticoids to tumor therapy in lymphoid cells are well studied, the impact to growth of prostate and other urological carcinomas is unknown.
Methods: We isolated cells from surgical resections of 21 prostate tumors and measured apoptosis and viability in these primary cells and 17 established cell lines from human prostate, bladder, renal cell and testicular carcinomas.
Results: We found that dexamethasone induces resistance regarding exposure to several cytotoxic agents such as taxol, gemcitabine, cisplatin, 5-FU and gamma-irradiation in 86% of the freshly isolated prostate tumors and in 100% of the established urological cell lines. No difference in dexamethasone-mediated protection was found in normal, benign and malignant prostate tumors.
Conclusions: These data show for the first time that dexamethasone induced therapy resistance in urological carcinomas is not the exception but a more common phenomenon and implicate that glucocorticoids may have two faces in cancer therapy, a beneficial and a dangerous one.