title: Prostaglandin E₂ receptor EP1-mediated phosphorylation of focal adhesion kinase enhances cell adhesion and migration in hepatocellular carcinoma cells.
abstract: The prostaglandin E₂ (PGE₂) EP1 receptor has been implicated in hepatocellular carcinoma (HCC) cell invasion. However, little is known about the mechanisms of EP1 receptor-mediated cell adhesion and migration. We previously showed that PGE₂ promotes cell adhesion and migration by activating focal adhesion kinase (FAK). The present study was designed to elucidate the association between the EP1 receptor and FAK activation in HCC cells and to investigate the related signaling pathways. The effects of PGE₂, EP1 agonist 17-phenyl trinor-PGE₂ (17-PT-PGE₂), PKC and EGFR inhibitors on FAK activation were investigated by treatment of Huh-7 cells. Phosphorylation of FAK Y397 and c-Src Y416 was investigated by western blotting. Cell adhesion and migration were analyzed by WST and transwell assays, respectively. Protein kinase C (PKC) activity was measured with a PKC assay kit. The results showed that 17-PT-PGE₂ (3 µM) increased FAK Y397 phosphorylation by more than 2-fold and promoted cell adhesion and migration in Huh-7 cells. In transfected 293 cells, expression of the EP1 receptor was confirmed to upregulate FAK phosphorylation, while the EP1 receptor antagonist sc-19220 decreased PGE₂-mediated FAK activation. PKC activity and c-Src Y416 phosphorylation were enhanced after 17-PT-PGE₂ treatment. Both PKC and c-Src inhibitor suppressed the 17-PT-PGE₂-upregulated FAK phosphorylation, as well as 17-PT-PGE₂-induced cell adhesion and migration. In addition, exogenous epidermal growth factor (EGF) treatment increased FAK phosphorylation. The EGF receptor (EGFR) inhibitor also suppressed 17-PT-PGE₂-upregulated FAK phosphorylation. Our study suggests that the PGE₂ EP1 receptor regulates FAK phosphorylation by activating the PKC/c-Src and EGFR signal pathways, which may coordinately regulate adhesion and migration in HCC.
authors.affiliation: Cancer Center, Department of Pathology, Nanjing Medical University, Nanjing 210029, PR China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Bai
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Juan
authors.initials: J
authors.lastname: Ma
authors.forename: Hai
authors.initials: H
authors.lastname: Zhang
authors.forename: Shukai
authors.initials: S
authors.lastname: Xia
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Xiuping
authors.initials: X
authors.lastname: Ma
authors.forename: Yan
authors.initials: Y
authors.lastname: Guo
authors.forename: Rong
authors.initials: R
authors.lastname: Rong
authors.forename: Shanyu
authors.initials: S
authors.lastname: Cheng
authors.forename: Wei
authors.initials: W
authors.lastname: Shu
authors.forename: Yipin
authors.initials: Y
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Leng
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion / Q000235:genetics; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D015232:Dinoprostone / Q000819:agonists / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D058306:Receptors, Prostaglandin E, EP1 Subtype / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: C092396:17-phenyltrinorprostaglandin E2; C545635:PTGER1 protein, human; D058306:Receptors, Prostaglandin E, EP1 Subtype; C512478:EGFR protein, human; D066246:ErbB Receptors; D051416:Focal Adhesion Protein-Tyrosine Kinases; D011493:Protein Kinase C; D015232:Dinoprostone