title: Role of LPAR3, PKC and EGFR in LPA-induced cell migration in oral squamous carcinoma cells.
abstract: BACKGROUND
  Oral squamous cell carcinoma is an aggressive neoplasm with serious morbidity and mortality, which typically spreads through local invasive growth. Lysophosphatidic acid (LPA) is involved in a number of biological processes, and may have a role in cancer cell migration and invasiveness. LPA is present in most tissues and can activate cells through six different LPA receptors (LPAR1-6). Although LPA is predominantly promigratory, some of the receptors may have antimigratory effects in certain cells. The signalling mechanisms of LPA are not fully understood, and in oral carcinoma cells the specific receptors and pathways involved in LPA-stimulated migration are unknown.
  
  
  METHODS
  The oral carcinoma cell lines E10, SCC-9, and D2 were investigated. Cell migration was studied in a scratch wound assay, and invasion was demonstrated in organotypic three dimensional co-cultures. Protein and mRNA expression of LPA receptors was studied with Western blotting and qRT-PCR. Activation of signalling proteins was examined with Western blotting and isoelectric focusing, and signalling mechanisms were further explored using pharmacological agents and siRNA directed at specific receptors and pathways.
  
  
  RESULTS
  LPA stimulated cell migration in the two oral carcinoma cell lines E10 and SCC-9, but was slightly inhibitory in D2. The receptor expression profile and the effects of specific pharmacological antagonist and agonists indicated that LPA-stimulated cell migration was mediated through LPAR3 in E10 and SCC-9. Furthermore, in both these cell lines, the stimulation by LPA was dependent on PKC activity. However, while LPA induced transactivation of EGFR and the stimulated migration was blocked by EGFR inhibitors in E10 cells, LPA did not induce EGFR transactivation in SCC-9 cells. In D2 cells, LPA induced EGFR transactivation, but this was associated with slowing of a very high inherent migration rate in these cells.
  
  
  CONCLUSIONS
  The results demonstrate LPA-stimulated migration in oral carcinoma cells through LPAR3, mediated further by PKC, which acts either in concert with or independently of EGFR transactivation.
authors.affiliation: Department of Pharmacology, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, and Oslo University Hospital, Blindern, P,O, Box 1057, Oslo N-0316, Norway. i.j.brusevold@medisin.uio.no.
authors.forename: Ingvild J
authors.initials: IJ
authors.lastname: Brusevold
authors.forename: Ingun H
authors.initials: IH
authors.lastname: Tveteraas
authors.forename: Monica
authors.initials: M
authors.lastname: Aasrum
authors.forename: John
authors.initials: J
authors.lastname: Ødegård
authors.forename: Dagny L
authors.initials: DL
authors.lastname: Sandnes
authors.forename: Thoralf
authors.initials: T
authors.lastname: Christoffersen
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D066246:ErbB Receptors / Q000096:biosynthesis / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008246:Lysophospholipids / Q000008:administration & dosage; D009062:Mouth Neoplasms / Q000235:genetics* / Q000473:pathology; D011493:Protein Kinase C / Q000235:genetics; D049368:Receptors, Lysophosphatidic Acid / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D008246:Lysophospholipids; D049368:Receptors, Lysophosphatidic Acid; D066246:ErbB Receptors; D011493:Protein Kinase C; C032881:lysophosphatidic acid