Effect of antioxidants on androgen-induced AP-1 and NF-kappaB DNA-binding activity in prostate carcinoma cells.

BACKGROUND: Previous studies have suggested that male hormones (androgens) and certain forms of oxygen (reactive oxygen species) are linked to the development of prostate cancer. We hypothesized that androgens contribute to prostate carcinogenesis by increasing oxidative stress. We further hypothesized that antioxidants reduce prostate cancer risk by modulating androgen effects on cellular processes. METHODS: To test these hypotheses, we looked for 1) a change in the level of reactive oxygen species in the presence of androgens, 2) androgen-induced binding activity of transcriptional activators AP-1 and NF-kappaB, whose activities are known to be altered during cell proliferation, and 3) the effect of antioxidants on androgen-induced transcription factor binding. RESULTS: Physiologic concentrations (1 nM) of 5alpha-dihydrotestosterone or 1-10 nM R1881, a synthetic androgen, produced sustained elevation of AP-1 and NF-kappaB DNA-binding activity in LNCaP cells, an androgen-responsive human prostate carcinoma cell line. Androgen-independent DU145 cells (another human prostate carcinoma cell line) were unaffected by R1881 treatment. AP-1-binding activity increased 5 hours after 1 nM R1881 treatment; NF-kappaB DNA-binding activity increased after 36 hours. Both activities remained elevated for at least 120 hours. Nuclear AP-1 and NF-kappaB protein levels were not elevated. Antioxidant vitamins C plus E blocked both androgen-induced DNA-binding activity and production of reactive oxygen species. CONCLUSION: Physiologic concentrations of androgens induce production of reactive oxygen species and cause prolonged AP-1 and NF-kappaB DNA-binding activities, which are diminished by vitamins C and E.

Prooxidant-antioxidant shift induced by androgen treatment of human prostate carcinoma cells.

BACKGROUND: Prostate cancer is a disease associated with aging. Also commonly associated with increasing age is a shift in the prooxidant-antioxidant balance of many tissues toward a more oxidative state, i.e., increased oxidative stress. We hypothesize that androgen exposure, which has long been associated with the development of prostate cancer, may be a means by which the prooxidant-antioxidant balance of prostate cells is altered. PURPOSE: Using established prostate carcinoma cell lines, we studied the effect of androgens on various parameters of oxidative state (e.g., generation of hydrogen peroxide and hydroxyl radicals, lipid peroxidation, and oxygen consumption) and antioxidant defense mechanisms (e.g., the glutathione system and catalase). METHODS: The androgen-responsive LNCaP and the androgen-independent DU145 prostate carcinoma cell lines were exposed to 5 alpha-dihydrotestosterone (DHT) and to the synthetic androgen R1881. The cellular proliferation responses were measured by use of a fluorometric assay to quantitate the amount of DNA. The generation of reactive oxygen species was measured by use of 2',7'-dichlorofluorescin diacetate, a dye that fluoresces in the presence of hydrogen peroxide or hydroxyl radicals. Lipid peroxidation was quantitated by use of a chromogen specific for malonaldehyde and 4-hydroxy-2(E)-nonenal. General mitochondrial activity was determined by assaying 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction. A Clark-type electrode was used to assess oxygen consumption per cell. Intracellular glutathione concentrations and the activities of catalase and gamma-glutamyl transpeptidase were measured spectrophotometrically. All P values resulted from two-sided tests. RESULTS: DHT at less than 1 to 100 nM (a concentration range encompassing the physiologic levels of DHT considering all ages) and R1881 at 0.1-1 nM concentrations were effective in inducing in LNCaP cells comparable proliferative responses and changes in oxidative stress. In contrast, neither DHT nor R1881 had any effect on the oxidative stress in DU145 cells. The mitochondrial activity in LNCaP cells, as measured by MTT reduction, was significantly elevated above the levels of the untreated controls by DHT (0.1-1000 nM) and R1881 (0.05-1 nM) (P < .001 in both). Oxygen consumption and catalase activity were increased in LNCaP cells in the presence of 1 nM R1881 by 60% and 40%, respectively, over the values in the untreated control cells (P < .03 and P < .01, respectively). The same concentration of R1881 resulted in a decrease in intracellular glutathione concentrations and an increase in gamma-glutamyl transpeptidase activity in LNCaP cells. Treatment with the oxidizing agents H2O2 and menadione produced an increase in gamma-glutamyl transpeptidase activity in LNCaP cells, whereas treatment with the antioxidant compound ascorbic acid (100 mM) reduced the oxidative stress produced in LNCaP cells by 1 nM R1881 and completely blocked the gamma-glutamyl transpeptidase activity. CONCLUSIONS: Physiologic levels of androgens are capable of increasing oxidative stress in androgen-responsive LNCaP prostate carcinoma cells. The evidence suggests that this result is due in part to increased mitochondrial activity. Androgens also alter intracellular glutathione levels and the activity of certain detoxification enzymes, such as gamma-glutamyl transpeptidase, that are important for maintenance of the cellular prooxidant-antioxidant balance.

Chronic care needs to be a higher priority.

Although acute care remains the focus of the U.S. health care delivery system, a shift is taking place toward chronic-illness mortality. Developing effective chronic-disease management processes is tough in the context of today's acute care orientation, according to William F. Henry, president of ForeSight Strategy Associates, St. Paul, MN.

Home care for children dying of cancer.

The feasibility of home care as an alternative to hospitalization for children dying of cancer was studied. The home care system was defined as nurse-directed with a consultant physician and did not entail extensive participation by other health professionals. Of 58 children cared for at home during the 2-year project, 79% died at home and 21% died in the hospital or en route to it. The findings, as shown by interview data, suggest that home care at the end stage of life is a viable alternative for children dying of cancer and for their families.

Psychosocial factors seen as problems by family practice residents and their spouses.

Residents and spouses in the University of Minnesota Family Practice Program were surveyed using an inventory relating to psychosocial stresses in their lives. Faculty realized that the residency period of education was a process of critical role transition. Adequate adaptation made to stresses is related to the learning environment. The survey revealed that central concerns are leisure/time scarcity problems, domestic/spouse complaints, conflicting demands on study needs, lack of self confidence, reservations about medicine as a career choice, decrease in sexual expression, parenting worries, and communication deficiencies. Empirical data on stresses give rise to some program modifications and to further research.