title: FAK is a critical regulator of neuroblastoma liver metastasis.
abstract: Neuroblastomas express increased levels of gastrin-releasing peptide receptor (GRP-R). However, the exact molecular mechanisms involved in GRP-R-mediated cell signaling in neuroblastoma growth and metastasis are unknown. Here, we report that focal adhesion kinase (FAK), as a critical downstream target of GRP-R, is an important regulator of neuroblastoma tumorigenicity. We found that FAK expression correlates with GRP-R expression in human neuroblastoma sections and cell lines. GRP-R overexpression in SK-N-SH cells increased FAK, integrin α3 and β1 expressions and cell migration. These cells demonstrated flatter cell morphology with broad lamellae, in which intense FAK expression was localized to the leading edges of lamellipodia. Interestingly, FAK activation was, in part, dependent on integrin α3 and β1 expression. Conversely, GRP-R silencing decreased FAK as well as Mycn levels in BE(2)-C cells, which displayed a denser cellular morphology. Importantly, rescue experiments in GRP-R silenced BE(2)-C cells showed FAK overexpression significantly enhanced cell viability and soft agar colony formation; similarly, FAK overexpression in SK-N-SH cells also resulted in increased cell growth. These effects were reversed in FAK silenced BE(2)-C cells in vitro as well as in vivo. Moreover, we evaluated the effect of FAK inhibition in vivo. FAK inhibitor (Y15) suppressed GRP-induced neuroblastoma growth and metastasis. Our results indicate that FAK is a critical downstream regulator of GRP-R, which mediates tumorigenesis and metastasis in neuroblastoma.
authors.affiliation: Departments of Pediatric Surgery, Vanderbilt University Medical Center1, Nashville, TN, USA.
authors.forename: Sora
authors.initials: S
authors.lastname: Lee
authors.forename: Jingbo
authors.initials: J
authors.lastname: Qiao
authors.forename: Pritha
authors.initials: P
authors.lastname: Paul
authors.forename: Kathleen L
authors.initials: KL
authors.lastname: O'Connor
authors.forename: Mark B
authors.initials: MB
authors.lastname: Evers
authors.forename: Dai H
authors.initials: DH
authors.lastname: Chung
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation; D048430:Cell Shape; D004789:Enzyme Activation; D051417:Focal Adhesion Kinase 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D039422:Integrin alpha3 / Q000378:metabolism*; D019012:Integrin beta1 / Q000378:metabolism; D008113:Liver Neoplasms / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics / Q000556:secondary*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D000071447:N-Myc Proto-Oncogene Protein; D009361:Neoplasm Invasiveness; D009447:Neuroblastoma / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics / Q000556:secondary*; D009687:Nuclear Proteins / Q000378:metabolism; D015513:Oncogene Proteins / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011554:Pseudopodia / Q000201:enzymology; D034622:RNA Interference; D018004:Receptors, Bombesin / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D023041:Xenograft Model Antitumor Assays
chemical_list: D039422:Integrin alpha3; D019012:Integrin beta1; C459801:MYCN protein, human; D000071447:N-Myc Proto-Oncogene Protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D047428:Protein Kinase Inhibitors; D018004:Receptors, Bombesin; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human