Abstract:【Objective】 To explore the effect of prostaglandin E receptor 4(EP4) on the growth of human papillary thyroid carcinoma cell line TPC -1. 【Methods】 Human papillary thyroid carcinoma cell line TPC -1 and human thyroid follicular epithelial cell line Nthy -ori 3 -1 were cultured. ELISA assay was used to measure the level of PGE2 in cell supernatants. The mRNA expression of four EP receptor subtypes(EP1

EP2

EP3 and EP4) was examined by quantitative real -time PCR(qRT -PCR). The levels of EP1 -4

PKA and PI3K(p110α and p110γ) protein were determined by Western blotting. The effects of selective EP4 antagonist L -161982 on cell viability were determined using MTT assay. 【Results】 PGE2 production can be detected in both TPC -1 and Nthy -ori 3 -1 cells. EP2 and EP4 expression appeared to increase in TPC -1 cells compared with Nthy -ori 3 -1 cells(P < 0.05). Meanwhile

TPC -1 cells expressed elevated protein levels for PI3K isoforms p110α and p110γ in comparison withNthy -ori 3 -1 cells(P < 0.05).L -161982 decreased TPC -1 cell viability in a dose -dependent manner(P < 0.05). 【Conclusion】 EP4 antagonist L -161982 can inhibit the growth of TPC -1 cells.