title: NET1-mediated RhoA activation facilitates lysophosphatidic acid-induced cell migration and invasion in gastric cancer.
abstract: The most lethal aspects of gastric adenocarcinoma (GA) are its invasive and metastatic properties. This aggressive phenotype remains poorly understood. We have recently identified neuroepithelial cell transforming gene 1 (NET1), a guanine exchange factor (GEF), as a novel GA-associated gene. Neuroepithelial cell transforming gene 1 expression is enhanced in GA and it is of functional importance in cell invasion. In this study, we demonstrate the activity of NET1 in driving cytoskeletal rearrangement, a key pathological mechanism in gastric tumour cell migration and invasion. Neuroepithelial cell transforming gene 1 expression was increased 10-fold in response to treatment with lysophosphatidic acid (LPA), resulting in an increase in active levels of RhoA and a 2-fold increase in cell invasion. Lysophosphatidic acid-induced cell invasion and migration were significantly inhibited using either NET1 siRNA or a RhoA inhibitor (C3 exoenzyme), thus indicating the activity of both NET1 and RhoA in gastric cancer progression. Furthermore, LPA-induced invasion and migration were also significantly reduced in the presence of cytochalasin D, an inhibitor of cytoskeletal rearrangements. Neuroepithelial cell transforming gene 1 knockdown resulted in AGS cell rounding and a loss of actin filament organisation, demonstrating the function of NET1 in actin organisation. These data highlight the importance of NET1 as a driver of tumour cell invasion, an activity mediated by RhoA activation and cytoskeletal reorganisation.
authors.affiliation: UCD Clinical Research Center, UCD School of Medicine and Medical Sciences, Mater Misericordiae University Hospital, 49-51 Eccles Street, Dublin 7, Ireland.
authors.forename: D
authors.initials: D
authors.lastname: Murray
authors.forename: G
authors.initials: G
authors.lastname: Horgan
authors.forename: P
authors.initials: P
authors.lastname: Macmathuna
authors.forename: P
authors.initials: P
authors.lastname: Doran
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000187:drug effects / Q000378:metabolism; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D005434:Flow Cytometry; D015870:Gene Expression; D006801:Humans; D008246:Lysophospholipids / Q000494:pharmacology*; D009361:Neoplasm Invasiveness / Q000503:physiopathology*; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D034622:RNA Interference; D012333:RNA, Messenger / Q000032:analysis; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology; D020742:rhoA GTP-Binding Protein / Q000187:drug effects / Q000378:metabolism*
chemical_list: D003598:Cytoskeletal Proteins; D008246:Lysophospholipids; C099763:NET1 protein, human; D015513:Oncogene Proteins; D012333:RNA, Messenger; C066737:RHOA protein, human; D020742:rhoA GTP-Binding Protein; C032881:lysophosphatidic acid