title: Cross-talk between LPA1 and epidermal growth factor receptors mediates up-regulation of sphingosine kinase 1 to promote gastric cancer cell motility and invasion.
abstract: Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are lysophospholipid mediators of diverse cellular processes important for cancer progression. S1P is produced by two sphingosine kinases, SphK1 and SphK2. Expression of SphK1 is elevated in many cancers. Here, we report that LPA markedly enhanced SphK1 mRNA and protein in gastric cancer MKN1 cells but had no effect on SphK2. LPA also up-regulated SphK1 expression in other human cancer cells that endogenously express the LPA(1) receptor, such as DLD1 colon cancer cells and MDA-MB-231 breast cancer cells, but not in HT29 colon cancer cells or MDA-MB-453 breast cancer cells, which do not express the LPA(1) receptor. An LPA(1) receptor antagonist or down-regulation of its expression prevented SphK1 and S1P(3) receptor up-regulation by LPA. LPA transactivated the epidermal growth factor receptor (EGFR) in these cells, and the EGFR inhibitor AG1478 attenuated the increased SphK1 and S1P(3) expression induced by LPA. Moreover, down-regulation of SphK1 attenuated LPA-stimulated migration and invasion of MNK1 cells yet had no effect on expression of neovascularizing factors, such as interleukin (IL)-8, IL-6, urokinase-type plasminogen activator (uPA), or uPA receptor induced by LPA. Finally, down-regulation of S1P(3), but not S1P(1), also reduced LPA-stimulated migration and invasion of MKN1 cells. Collectively, our results suggest that SphK1 is a convergence point of multiple cell surface receptors for three different ligands, LPA, EGF, and S1P, which have all been implicated in regulation of motility and invasiveness of cancer cells.
authors.affiliation: Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298-0614, USA.
authors.forename: Dai
authors.initials: D
authors.lastname: Shida
authors.forename: Xianjun
authors.initials: X
authors.lastname: Fang
authors.forename: Tomasz
authors.initials: T
authors.lastname: Kordula
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Takabe
authors.forename: Sandrine
authors.initials: S
authors.lastname: Lépine
authors.forename: Sergio E
authors.initials: SE
authors.lastname: Alvarez
authors.forename: Sheldon
authors.initials: S
authors.lastname: Milstien
authors.forename: Sarah
authors.initials: S
authors.lastname: Spiegel
mesh_terms: D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation; D002633:Chemotaxis; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D008246:Lysophospholipids / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger; D049368:Receptors, Lysophosphatidic Acid / Q000378:metabolism*; D049349:Receptors, Lysosphingolipid / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D015854:Up-Regulation; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics / Q000378:metabolism; D000099157:Sphingosine Kinase
chemical_list: D066246:ErbB Receptors; D015850:Interleukin-6; D016209:Interleukin-8; D008246:Lysophospholipids; D017853:Phosphotransferases (Alcohol Group Acceptor); D012333:RNA, Messenger; D049368:Receptors, Lysophosphatidic Acid; D049349:Receptors, Lysosphingolipid; D013110:Sphingosine; D014568:Urokinase-Type Plasminogen Activator; D000099157:Sphingosine Kinase; C508606:CXCL8 protein, human; C508600:IL6 protein, human; C060506:sphingosine 1-phosphate; C032881:lysophosphatidic acid