title: Protein kinase C regulates bombesin-induced rapid VEGF secretion in neuroblastoma cells.
abstract: BACKGROUND
  Intracellular signaling responsible for gastrin-releasing peptide (GRP) receptor-mediated neovascularization is not clearly understood. We sought to determine the cellular mechanisms involved in the GRP receptor regulation of vascular endothelial growth factor (VEGF) release in neuroblastoma cells.
  
  
  METHODS
  BE(2)-C cells were treated with bombesin (BBS), the amphibian equivalent of GRP, Phorbol myristate acetate (PMA) a PKC agonist, or GF109293X (GFX), and analyses were performed for VEGF secretion, phosphorylated protein kinase B (AKT), extracellular signal-regulated kinases (ERK) and protein kinase D (PKD) expression.
  
  
  RESULTS
  BBS rapidly increased VEGF secretion at 30 min. Pre-treatment with PMA alone produced similar results; this effect was synergistic with the addition of GRP. Conversely, GFX blocked PMA-stimulated increase in VEGF secretion. Immunofluorescent staining for VEGF correlated to BBS, PMA and GFX.
  
  
  CONCLUSIONS
  PKC is critically responsible for rapid VEGF secretion by GRP receptor signaling in neuroblastoma cells. Inhibition of VEGF significantly reduced GRP-mediated cell proliferation, suggesting its crucial role in neuroblastoma tumorigenesis.
authors.affiliation: Department of Pediatric Surgery, 2200 Children's Way, DOT 7100, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Cameron
authors.initials: C
authors.lastname: Schlegel
authors.forename: Pritha
authors.initials: P
authors.lastname: Paul
authors.forename: Sora
authors.initials: S
authors.lastname: Lee
authors.forename: Kwang Woon
authors.initials: KW
authors.lastname: Kim
authors.forename: Nadja
authors.initials: N
authors.lastname: Colon
authors.forename: Jingbo
authors.initials: J
authors.lastname: Qiao
authors.forename: Dai H
authors.initials: DH
authors.lastname: Chung
mesh_terms: D015153:Blotting, Western; D001839:Bombesin / Q000494:pharmacology*; D045744:Cell Line, Tumor; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D019886:Gastrin-Releasing Peptide / Q000378:metabolism; D006801:Humans; D009389:Neovascularization, Pathologic / Q000378:metabolism; D009447:Neuroblastoma / Q000201:enzymology* / Q000378:metabolism* / Q000473:pathology; D011493:Protein Kinase C / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D042461:Vascular Endothelial Growth Factor A; D019886:Gastrin-Releasing Peptide; D011493:Protein Kinase C; D001839:Bombesin