OBJECTIVETo investigate the potential signaling pathway that regulates the proliferation of human CD34cells stimulated by prostaglandin E2 receptor 4 agonist (EP4A) in vitro.

METHODSTwenty samples of peripheral blood containing stem cells were collected from the G-CSF mobilized healthy donors in our department of hematology. Human CD34cells were isolated by magnetic activated cell sorting (MACS) microbeads kit. The Cell Counting Kit-8 (CCK8) assay was used to determine the optimal concentration and time of EP4A to promote human CD34cell proliferation in vitro. Under the optimal condition, quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect mRNA level of β-catenin, and Western blot was used to assay protein expression of β-catenin and P-GSK-3β in human CD34cells treated with EP4A.

RESULTSCulturing with 10 µmol/L EP4A for 72 h, it was found that EP4A promoted human CD34cell proliferation significantly, and the proliferation rate of human CD34cells was 1.36 times higher than that of the control(P=0.002). Under the optimal condition, it was also found that EP4A enhanced the β-catenin expression at both mRNA and protein levels, and up-regulated phosphorylation of GSK-3β in human CD34cells, but these effects could be inhibited by the EP4A antagonist EP4AA.

CONCLUSIONEP4A can enhance human CD34cell proliferation in vitro by activating Wnt/β-catenin signaling pathway.