Prostaglandin E2 upregulates survivin expression via the EP1 receptor in hepatocellular carcinoma cells

AimsCyclooxygenase-2 (COX-2)-controlled production of prostaglandin E2 (PGE2) has been implicated in cell growth and metastasis in many cancers. Recent studies have found that COX-2 is co-expressed with survivin in many cancers. Survivin is a member of the inhibitor-of-apoptosis protein family. Some COX-2 inhibitors (e.g., celecoxib) can reduce the expression of survivin. However, little is known about the mechanism of PGE2-mediated expression of survivin. This study was designed to uncover the effect of PGE2 on survivin expression in hepatocellular carcinoma cells.Main methodsThe effects of PGE2 and EP1 agonist on survivin expression were examined in HUH-7 and HepG2 cells. Plasmid transfection and EP1 siRNA were used to regulate the expression of COX-2 and the EP1 receptor protein.Key findingsPGE2 treatment increased survivin expression 2.3-fold. COX-2 overexpression resulted in a similar level of survivin upregulation. However, this effect was suppressed by treatment with celecoxib. EP1 receptor transfection or treatment with a selective EP1 agonist mimicked the effect of PGE2 treatment. Conversely, the PGE2-induced upregulation of survivin was blocked by treatment with a selective EP1 antagonist or siRNA against the EP1 receptor. The phosphorylation of EGFR and Akt were elevated in EP1 agonist-treated cells, and both EGFR and PI3K inhibitors suppressed the upregulation of survivin induced by PGE2 or EP1 agonist.SignificancePGE2 regulates survivin expression in hepatocellular carcinoma cells through the EP1 receptor by activating the EGFR/PI3K pathway. Targeting the PGE2/EP1/survivin signaling pathway may aid the development of new therapeutic strategies for both the prevention and treatment of this cancer.