Endocrine Abstracts

Previously we have demonstrated up-regulated expression of COX-2 and enhanced synthesis of PGE₂ in cervical carcinomas. (Sales et al. 2001. J. Clin. Endocrinol Metab. 86(5):2243-2249). Enhanced PGE₂ synthesis as a consequence of COX-2 overexpression has been associated with various carcinomas and is regarded as a promoter of neoplastic cell proliferation and angiogenesis. In sexually active women growth and invasiveness of neoplastic cervical cells may be also under the direct influence of PGE present in seminal plasma. The aim of this study was to investigate the effect of seminal plasma on the expression of COX-2 and the PGE₂ receptor subtypes EP2 and EP4 in HeLa (cervical epithelial) cells. The expression of COX-2, EP2 and EP4, was measured by real-time RT-PCR. Treatment of HeLa cells with seminal plasma for 24hrs resulted in up-regulation of expression of COX-2, EP2 and EP4 receptors (fold induction above basal was 20.25 plus/minus 9.26, 12.5 plus/minus 6.2 and 7.8 plus/minus 2.8 respectively; p less than 0.05). Co-treatment of cells with the dual COX-enzyme inhibitor indomethacin abolished the up-regulation in EP2/EP4 receptor expression. Treatment of cells with the selective COX-2 inhibitor NS-398, and the PKA inhibitor H-89 partially abolished the up-regulated receptor expression. Subsequently, we investigated the effect of seminal plasma on cAMP signalling in HeLa cells, as COX-2 expression is regulated via the cAMP-pathway, presumably via the cAMP-response element on the COX-2 promotor (Smith et al. 2000. Annu. Rev. Biochem. 69:145-182). Stimulation of HeLa cells for 5min with seminal plasma yielded a 12.8 plus/minus 5.68 fold increase in cAMP production compared with unstimulated cells (P less than 0.05). These data raise the possibility that, in sexually active women, seminal plasma may act in an autocrine/paracrine manner to modulate the COX-2/PGE₂ biosynthetic pathway and could thus play a role in regulating neoplastic cell function.