Background: Celecoxib, a selective cyclooxygenase (COX)-2 inhibitor, also has anti-proliferative properties and pro-apoptotic effects on different in vivo and in vitro models, two actions that may be efficacious in therapy for endometriosis. We evaluated the effects of celecoxib on apoptosis and proliferation, and vascular endothelial growth factor (VEGF) production and COX-2 expression and activity in endometrial epithelial cells (EECs).
Methods and results: Thirty-two endometriosis and 13 control women were included in the study. EECs from eutopic endometrium and control biopsies were cultured with different doses of celecoxib. Celecoxib at 50, 75 and 100 microM (versus vehicle control) inhibited EEC proliferation in cultures from controls (P < 0.05, P < 0.01 and P < 0.01, respectively) and patients with endometriosis (P < 0.05, P < 0.01 and P < 0.01), as assessed by (3)H-thymidine uptake. Celecoxib at 50, 75 and 100 microM induced apoptosis in EEC from controls (P < 0.05, P < 0.001 and P < 0.001) and patients with endometriosis (P < 0.001, P < 0.001 and P < 0.01), as revealed by the Acridine Orange-Ethidium Bromide technique. Western blot analysis showed that celecoxib was effective at increasing COX-2 protein at 100 microM in EEC from endometriosis patients (P < 0.05). In EEC from endometriosis patients, celecoxib at 25, 50 and 100 microM was also effective in reducing COX-2 activity, reflected in the reduction of prostaglandin E(2) (PGE(2)) synthesis (P < 0.001), and VEGF secretion (P < 0.001; P < 0.05 and P < 0.001), assessed by enzyme-linked immunosorbent assay. Exogenous PGE(2) did not reverse celecoxib-induced growth inhibition.
Conclusions: This study suggests a direct effect of celecoxib on reduction of endometrial growth and supports further research on selective COX-2 inhibition as a novel therapeutic modality in endometriosis.