Los polifenoles del vino ejercen su efecto antineoplásico sobre la línea celular PC-3 andrógeno resistente a través de la inhibición de la actividad transcripcional del promotor de COX-2 mediada por NF-kβ

Abstract

ObjectiveMediterranean diet may play a role in the prevention of prostate cancer (PCa) development and progression. Cyclooxygenase-2 (COX-2) expression is associated with increased cellular proliferation, prevents apoptosis and favors tumor invasion. We intend to clarify whether resveratrol and other polyphenols effectively inhibit COX-2 activity and induce apoptosis in hormone-resistant PC-3 cell line. Material and methodPC-3 cells were cultured and treated with different concentrations of gallic acid, tannic acid, quercetin, and resveratrol in presence of phorbol myristate acetate (PMA; 50μg/ml) that induces COX-2 expression. Total RNA was extracted and COX-2 expression was analyzed by relative quantification real-time PCR (ΔΔCt method). COX-2 activity was determined by PGE-2 detection using ELISA. Caspase 3/7 luminescence assay was used to disclose apoptosis. Transitory transfection with short human COX-2 (phPES2 -327/+59) and p5xNF-kβ-Luc plasmids determined COX-2 promoter activity and specifically that dependant of NF-kβ. ResultsCOX-2 expression was not modified in media devoid of PMA. However, under PMA induction tannic acid (2.08±.21), gallic acid (2.46±.16), quercetin (1.78±.14) and resveratrol (1.15±.16) significantly inhibited COX-2 mRNA with respect to control (3.14±.07), what means a 34%, 23%, 46% and 61% reduction, respectively. The inhibition in the levels of PGE-2 followed a similar pattern. All compounds studied induced apoptosis at 48h, although at a different rate. PMA caused a rise in activity 7.4±.23 times phPES2 -327/+59 and 2.0±.1 times p5xNF-kβ-Luc at 6h compared to basal. Resveratrol suppressed these effects 17.1±.21 and 32.4±.18 times, respectively. Similarly, but to a lesser extent, the rest of evaluated polyphenols diminished PMA inductor effect on the activity of both promoters. ConclusionsPolyphenols inhibit transcriptional activity of COX-2 promoter mediated by NF-kβ. This effect could explain, at least in part, the induction of apoptosis in vitro by these substances in castration resistant PCa.