Objective:To investigate the role of AREG in PGE2-induced proliferation of cholangiocarcinoma cells(CCLP1 cells). Methods:CCLP1 cells were treated with PGE2,EP1-4 receptor agonist,EP2 receptor antagonist H89,PKA inhibitor H89,cAMP inhibitor SQ22536. Western blot and WST were used to examine the expression of AREG protein and the cell proliferation ability in CCLP1 cells. Results:The level of AREG protein increased by 44.2%(P < 0.05) after treated with 10 μmol/L PGE2. It was previously proved that PGE2 could promote the proliferation of CCLP1 cells,however,this effect was obviously inhibited by 20% (P < 0.01) when CCLP1 cells were pretreated with the 20 μmol/L neutralizing-antibody(Mab262 and SAB1402118) of AREG. Then four selective EP receptor agonists(17-phenyltrinor Prostaglandin E2,Butaprost,Sulprostone and Prostaglandin E1 Alcohol) 10 μmol/L were used to stimulate CCLP1 cells,it were found that only EP2 agonist could induce the expression of AREG protein,increased by 20.1%(P < 0.05),whereas the other three agonists downregulated the protein expression of AREG. In agreement with this result,the expression of AREG protein improved by EP2 agonist was indeed suppressed by 20%,when CCLP1 cells were pretreated with 10 μmol/L AH6809,the EP2 antagonist. After treated with EP2 receptor agonist(10 μmol/L) for 24 h,the proliferation ability of CCLP1 cells increased by 26.5%. PKA inhibitor H89 and cAMP inhibitor SQ22536 can restrict the AREG protein increase induced by PGE2,and the AREG protein expression was downregulated by 54.4% and 46.6% respectively,compared with PGE2 treated group. It was reported that PGE2 could induce the phosphorylation of CREB in CCLP1 cells,which could bind and activate the CRE element of AREG promoter. However,H89 and SQ22536 could strikingly inhibit the phosphorylation of CREB induced by PGE2. At the same time,CMV500-DN-CREB plasmid was transfected into CCLP1 cells,resulting in a striking restriction of AREG protein expression induced by PGE2. Conclusion:Prostaglandin E2 might promote the cell proliferation of CCLP1 cells through EP2 receptor,which consequently upregulates the expression of AREG by activation of cAMP-PKA-CREB pathway.