OBJECTIVETo investigate the mechanisms responsible for epidermal growth factor (EGF)-induced proliferation of human esophageal squamous cell carcinoma cells.

METHODS(3)H-thymidine incorporation assay was used to assess the proliferation of HKESC-1 cells exposed to EGF stimulation. Enzyme immunoassay was used to measure PGE(2) release from HKESC-1 cells, and the protein levels of cyclooxygenase 1 (COX-1), COX-2, EP1 and EP2 in EGF-stimulated cells were determined by Western blotting.

RESULTSEGF upregulated COX-2 protein expression but produced no obvious effect on COX-1 protein expression in HKESC-1 cells. As a consequence of increased COX-2, EGF further enhanced cellular PGE(2) release. EGF stimulation also resulted in increased protein expression of EP2, a subtype of PGE(2) receptors. Both the non-selective COX inhibitor indomethacin and the selective COX-2 inhibitor SC-236 completely abolished EGF-induced PGE(2) release, and suppressed the mitogenic effect of EGF.

CONCLUSIONEGF stimulates the proliferation of HKESC-1 cells by increasing COX-2 protein expression and PGE(2) release. Upregulated EP2 protein expression may further amplify the mitogenic action of PGE(2).

Carcinoma, Squamous Cell ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclooxygenase 2 ; metabolism ; Dinoprostone ; metabolism ; Epidermal Growth Factor ; pharmacology ; Esophageal Neoplasms ; pathology ; Humans ; Pyrazoles ; pharmacology ; Receptors, Prostaglandin E, EP2 Subtype ; metabolism ; Sulfonamides ; pharmacology ; Up-Regulation ; drug effects

OBJECTIVETo investigate the effect of prostaglandin E2 (PGE(2)) on the proliferation of cultured hepatocellular carcinoma cells and explore which subtypes of EP prostanoid receptor mediate the action.

METHODSRT-PCR was used to determine COX-2 and EP receptor mRNA expression levels in human hepatocellular carcinoma cell line Hep3B and human normal hepatocyte line QSG7701. Cell counting kit-8 (CCK-8) assay was employed to investigate the effect of PGE(2), selective EP2 receptor agonist butaprost and EP3/EP4 receptor agonist PGE1 alcohol on the proliferation of the cells.

RESULTSCOX-2 mRNA was highly expressed in Hep3B cells but scarcely in QSG7701 cells. Hep3B cells expressed the mRNAs for all the EP receptor subtypes, but EP2 and EP4 receptors were much more strongly expressed than EP1 and EP3 receptors. PGE(2) significantly promoted Hep3B cell proliferation in a time- and dose-dependent manner, and 10 µmol/L PGE(2) increased the cell proliferation by 22.57% (P<0.001) after a 48-h incubation; treatment with 0.1, 1.0, and 10 µmol/L PGE(2) for 72 h resulted in significantly increased cell proliferation by 12.13% (P<0.01), 17.58% (P<0.01) and 33.07% (P<0.001), respectively. EP2 receptor agonist butaprost (20 µmol/L) increased Hep3B cell proliferation by 21.96% (P<0.001), but the EP3/EP4 receptor agonist PGE(1) alcohol (2-20 µmol/L) exhibited no significant mitogenic effect in Hep3B cells, and 200 µmol/L PGE(1) alcohol decreased the cell viability.

CONCLUSIONSelective activation of EP2 receptor promotes Hep3B cell proliferation, indicating the predominant role of EP2 receptor in mediating the mitogenic effect of PGE2.

Carcinoma, Hepatocellular ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclooxygenase 2 ; genetics ; metabolism ; Dinoprostone ; pharmacology ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Male ; RNA, Messenger ; genetics ; Receptors, Prostaglandin E, EP2 Subtype ; genetics ; metabolism

OBJECTIVETo investigate the effect of prostaglandins E2 (PGE2) in enhancing vascular endothelial growth factor (VEGF) expression in a rat macrophage cell line and the effect of the media from PGE2-inuced rat macrophages on angiogenetic ability of human umbilical vein endothelial cells (HUVECs) in vitro.

METHODSWestern blotting and qPCR were employed to investigate the expressions of VEGF protein and mRNAs in rat macrophage cell line NR8383 stimulated by PGE2 in the presence or absence of EP2 receptor inhibitor (AH6809) and EP4 receptor inhibitor (AH23848). Conditioned supernatants were obtained from different NR8383 subsets to stimulate HUVECs, and the tube formation ability and migration of the HUVECs were assessed with Transwell assay.

RESULTSPGE2 stimulation significantly enhanced the expression of VEGF protein and mRNAs in NR8383 cells in a dose-dependent manner. The supernatants from NR8383 cells stimulated by PGE2 significantly enhanced tube formation ability of HUVECs (P<0.05) and promoted the cell migration. Such effects of PGE2 were blocked by the application of AH6809 and AH23848.

CONCLUSIONPGE2 can dose-dependently increase VEGF expression in NR8383 cells, and the supernatants derived from PGE2-stimulated NR8383 cells can induce HUVEC migration and accelerate the growth of tube like structures. PGE2 are essential to corpus luteum formation by stimulating macrophages to induce angiogenesis through EP2/EP4.

Animals ; Cell Line ; Cell Movement ; Cells, Cultured ; Culture Media, Conditioned ; pharmacology ; Dinoprostone ; pharmacology ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; Humans ; Macrophages ; chemistry ; Neovascularization, Pathologic ; RNA, Messenger ; Rats ; Receptors, Prostaglandin E, EP2 Subtype ; metabolism ; Receptors, Prostaglandin E, EP4 Subtype ; metabolism ; Vascular Endothelial Growth Factor A ; Xanthones ; pharmacology