PROSTAGLANDIN E2 stimulates cancer-related phenotypes in prostate cancer PC3 cells through cyclooxygenase-2.

Cyclooxygenase (COX)-derived prostaglandin E2 (PGE2 ) affects many mechanisms that have been shown to play roles in carcinogenesis. Recently, we found that, in androgen-independent prostate cancer PC3 cells, PGE2 acts through an intracrine mechanism by which its uptake by the prostaglandin transporter (PGT) results in increased intracellular PGE2 (iPGE2 ), leading to enhanced cell proliferation, migration, invasion, angiogenesis, and loss of cell adhesion to collagen I. These iPGE2 -mediated effects were dependent on hypoxia-inducible factor 1-α (HIF-1α), whose expression increased upon epidermal growth factor receptor (EGFR) transactivation by a subset of intracellular PGE2 receptors. Here, we aimed to study the role of COX in PGE2 protumoral effects in PC3 cells and found that the effects were prevented by inhibition of COX-2, which highlights its crucial role amplifying the levels of iPGE2 . Treatment with exogenous PGE2 determined a transcriptional increase in COX-2 expression, which was abolished by genetic or pharmacologic inhibition of PGT. PGE2 -induced increase in COX-2 expression and, thereby, in transcriptional increase in HIF-1α expression was due to EGFR activation, leading to the activation of Phosphoinositide 3-kinase/Akt, Extracellular signal -regulated kinases 1/2, p38 and Mitogen- and stress-activated protein kinase-1 (PI3K/Akt, Erk1/2, p38 and MSK-1). Collectively, the data suggest that EGFR-dependent COX-2 upregulation by a novel positive feedback loop triggered by iPGE2 underlies the intracrine pro-tumoral effects of PGE2 in PC3 cells. Therefore, this feedback loop may be relevant in prostate cancer for the maintenance of PGE2 -dependent cancer cell growth through amplifying the activity of the COX-2 pathway.

Intracrine prostaglandin E2 pro-tumoral actions in prostate epithelial cells originate from non-canonical pathways.

Prostaglandin E2 (PGE2 ) increases cell proliferation and stimulates migratory and angiogenic abilities in prostate cancer cells. However, the effects of PGE2 on non-transformed prostate epithelial cells are unknown, despite the fact that PGE2 overproduction has been found in benign hyperplastic prostates. In the present work we studied the effects of PGE2 in immortalized, non-malignant prostate epithelial RWPE-1 cells and found that PGE2 increased cell proliferation, cell migration, and production of vascular endothelial growth factor-A, and activated in vitro angiogenesis. These actions involved a non-canonic intracrine mechanism in which the actual effector was intracellular PGE2 (iPGE2 ) instead of extracellular PGE2 : inhibition of the prostaglandin uptake transporter (PGT) or antagonism of EP receptors prevented the effects of PGE2 , which indicated that PGE2 activity depended on its carrier-mediated translocation from the outside to the inside of cells and that EP receptors located intracellularly (iEP) mediated the effects of PGE2 . iPGE2 acted through transactivation of epidermal growth factor-receptor (EGFR) by iEP, leading to increased expression and activity of hypoxia-inducible factor-1α (HIF-1α). Interestingly, iPGE2 also mediates the effects of PGE2 on prostate cancer PC3 cells through the axis iPGE2 -iEP receptors-EGFR-HIF-1α. Thus, this axis might be responsible for the growth-stimulating effects of PGE2 on prostate epithelial cells, thereby contributing to prostate proliferative diseases associated with chronic inflammation. Since this PGT-dependent non-canonic intracrine mechanism of PGE2 action operates in both benign and malignant prostate epithelial cells, PGT inhibitors should be tested as a novel therapeutic modality to treat prostate proliferative disease.

The effect of the European traditional use directive on the register of herbal medicinal products in Spain / Efecto en España de la directiva Europea de uso tradicional sobre el registro de medicamentos a base de plantas

Background: Directive 2004/24/EC, which came into force in 2011, created new regulatory requirements for traditional herbal medicines (THM). This study compared the Spanish THM registry before and after the Directive came fully into force in 2011. Methods: We consulted the herbal medicinal plant and drug catalogues (General Council of the Official Colleges of Pharmacists), the website of the European Medicines Agency (EMA), and retail web sites. Results: Of 315 THM (from 39 companies) licensed in Spain in 2010, only 48 (10 companies) remained licensed in 2013, mainly due to their withdrawal: the EMA had received just 123 applications from Spain and at least 34% formerly licensed THM had shifted to the less strictly regulated food sector, while up to 54% might have disappeared from the market. However, there is still a significant presence of retail websites making illegal health claims. Conclusion: In Spain, the public health benefits of the Directive 2004/24/EC might be less than expected (AU)

Antecedentes: En 2011 entró totalmente en vigor la Directiva 2004/24/CE, que impone nuevos requerimientos a los medicamentos tradicionales a base de plantas. Este trabajo analiza el efecto sobre su registro en España. Métodos: Se consultaron los catálogos de plantas medicinales y de medicamentos (CGCOF), la página web de la Agencia Europea del Medicamento (EMA) y sitios de venta en Internet. Resultados: De los 315 medicamentos a base de plantas autorizados en 2010, procedentes de 39 compañías; solo quedaban 48 (10 compañías) en 2013 por renuncia de la mayoría: sólo 123 solicitudes fueron recibidas a la EMA y al menos un 34% se pasó al sector de alimentación (menos estrictamente regulado). Hasta un 54% podría no comercializarse actualmente. Sin embargo, existe una presencia significativa de sitios web anunciando ilegalmente propiedades saludables para sus productos. Conclusión: Los beneficios de la Directiva 2004/24/CE para la salud pública española podrían ser menos de los esperados (AU)

The effect of the European traditional use directive on the register of herbal medicinal products in Spain.

BACKGROUND: Directive 2004/24/EC, which came into force in 2011, created new regulatory requirements for traditional herbal medicines (THM). This study compared the Spanish THM registry before and after the Directive came fully into force in 2011. METHODS: We consulted the herbal medicinal plant and drug catalogues (General Council of the Official Colleges of Pharmacists), the website of the European Medicines Agency (EMA), and retail web sites. RESULTS: Of 315 THM (from 39 companies) licensed in Spain in 2010, only 48 (10 companies) remained licensed in 2013, mainly due to their withdrawal: the EMA had received just 123 applications from Spain and at least 34% formerly licensed THM had shifted to the less strictly regulated food sector, while up to 54% might have disappeared from the market. However, there is still a significant presence of retail websites making illegal health claims. CONCLUSION: In Spain, the public health benefits of the Directive 2004/24/EC might be less than expected.

Role of intracellular prostaglandin E2 in cancer-related phenotypes in PC3 cells.

Prostaglandin E2 (PGE2) and hypoxia-inducible factor-1α (HIF-1α) affect many mechanisms that have been shown to play a role in prostate cancer. In PGE2-treated LNCaP cells, up-regulation of HIF-1α requires the internalization of PGE2, which is in sharp contrast with the generally accepted view that PGE2 acts through EP receptors located at the cell membrane. Here we aimed to study in androgen-independent PC3 cells the role of intracellular PGE2 in several events linked to prostate cancer progression. To this end, we used bromocresol green, an inhibitor of prostaglandin uptake that blocked the immediate rise in intracellular immunoreactive PGE2 following treatment with 16,16-dimethyl-PGE2. Bromocresol green prevented the stimulatory effect of 16,16-dimethyl-PGE on cell proliferation, adhesion, migration and invasion and on HIF-1α expression and activity, the latter assessed as the HIF-dependent activation of (i) a hypoxia response element-luciferase plasmid construct, (ii) production of angiogenic factor vascular endothelial growth factor-A and (iii) in vitro angiogenesis. The basal phenotype of PC3 cells was also affected by bromocresol green, that substantially lowered expression of HIF-1α, production of vascular endothelial growth factor-A and cell proliferation. These results, and the fact that we found functional intracellular EP receptors in PC3 cells, suggest that PGE2-dependent intracrine mechanisms play a role in prostate cancer Therefore, inhibition of the prostaglandin uptake transporter might be a novel therapeutic approach for the treatment of prostate cancer.