Estrogen receptors regulate galectin­3 in androgen­independent DU­145 prostate cancer cells.

The aim of the present study was to investigate the role of estrogen receptor (ER)α and ERß, and galectin­3 (GAL­3) in migration and invasion of androgen­independent DU­145 prostate cancer cells, and to examine the regulation of the expression of GAL­3 by the activation of these receptors. Wound healing and cell invasion assays were performed using the control (basal level of cellular function) and treated DU­145 cells. At 24 h of treatment, 17ß­estradiol (E2), the ERα­selective agonist, 4,4',4"­(4­propyl­(1H)­pyrazole­1,3,5­triyl)trisphenol (PPT), or the ERß­selective agonist, 2,3­bis(4­hydroxyphenyl)­propionitrile (diarylprepionitrile; DPN), increased the migration and invasion of the DU­145 cells. Pre­treatment with the ERα­ and ERß­selective antagonists blocked these effects, indicating that ERα and ERß are upstream receptors regulating these processes. Western blot analysis and immunofluorescence staining for the detection of the GAL­3 were performed using the control and treated DU­145 cells. Treatment of the DU­145 cells with E2, PPT or DPN for 24 h increased the expression of the GAL­3 compared to the control. Furthermore, a specific inhibitor of GAL­3 (VA03) inhibited the migration and invasion of DU­145 cells, indicating the involvement of the complex ERα/GAL­3 and ERß/GAL­3 in the regulation of these processes. On the whole, the present study demonstrates that the activation of both ERs increases the expression and signaling of GAL­3, and promotes the migration and invasion of DU­145 cells. The findings of the present study provide novel insight into the signatures and molecular mechanisms of ERα and ERß in DU­145 cells.

Estrogen receptors localization and signaling pathways in DU-145 human prostate cancer cells.

The aim of the present study was to investigate the subcellular localization of estrogen receptors ERα and ERß in androgen-independent prostate cancer cell line DU-145, and the possible role of exportin CRM1 on ERs distribution. In addition, we evaluated the ERs contribution to activation of ERK1/2 and AKT. Immunostaining of ERα and ERß was predominantly found in the extranuclear regions of DU-145 cells. CRM1 inhibitor Leptomycin B reduced drastically the presence of ERα and ERß in the extranuclear regions and increased in the nuclei, indicating the possible involvement of CRM1 on ERs nuclear-cytoplasmic shuttling. 17ß-estradiol (E2), ERα-selective agonist PPT and ERß-selective agonist DPN induced a rapid increase on ERK1/2 phosphorylation. E2-induced ERK1/2 activation was partially inhibited when cells were pretreated with ERα- or ERß-selective antagonists, and blocked by simultaneous pretreatment with both antagonists, suggesting ERα/ß heterodimers formation. Furthermore, E2 treatment did not activate AKT pathway. Therefore, we highlighted a possible crosstalk between extranuclear and nuclear ERs and their upstream and downstream signaling molecules as an important mechanism to control ER function as a potential therapeutic target in prostate cancer cells.