Prostaglandin E 2 (PGE 2 ) has been shown to induce expression of vascular endothelial growth factor (VEGF) and other signaling molecules in several cancers. PGE 2 elicits its functions though four G-protein coupled membrane receptors (EP1-4). In this study, we investigated the role of EP receptors in PGE 2 -induced molecular events in prostate cancer cells. qRT-PCR analysis revealed that PC-3 cells express a substantially higher level of EP2 and moderately higher EP4 than DU145 and LNCaP cells. LNCaP cells had virtually no detectable EP2 mRNA. EP1 and EP3 mRNAs were not detected in these cells. Treatment of prostate cancer cells with PGE 2 (1 nM-10 mM) increased both VEGF secretion and cyclic adenosine monophosphate (cAMP) production. Levels of induction in PC-3 cells were greater than in DU145 and LNCaP cells. The selective EP2 agonist CAY10399 also significantly increased VEGF secretion and cAMP production in PC-3 cells, but not in DU145 and LNCaP cells. Moreover, PGE 2 and CAY10399 increased mitogen activated protein kinase/extracellular signal regulated kinase (MAPK/Erk) and Akt phosphorylation in PC-3 and DU145 cells, but not in LNCaP cells. However, neither the MAPK/Erk inhibitor U0126 nor the PI3K/Akt inhibitor LY294002 abolished PGE 2induced VEGF secretion in PC-3 cells. We further demonstrated that the adenylate cyclase activator forskolin and the cAMP anologue 8-bromo-cAMP mimicked the effects of PGE 2 on VEGF secretion in PC-3 cells. Meanwhile, the adenylate cyclase inhibitor 2 0 5 0 -dideoxyadenosine, at concentrations that inhibited PGE 2 -induced cAMP, significantly blocked PGE 2 -induced VEGF secretion in PC-3 cells. We conclude that PGE 2 -induced VEGF secretion in prostate cancer cells is mediated through EP2-, and possibly EP4-, dependent cAMP signaling pathways.