title: RhoA/ROCK signaling mediates plasticity of scirrhous gastric carcinoma motility.
abstract: The small guanosine triphosphatase (GTPase) Rho and its downstream effector Rho-associated kinase (ROCK) is one of a key mediator involved in controlling focal adhesions and the dynamics of actin stress fibers. The molecular mechanisms for the function of Rho/ROCK pathway leading to the progression in scirrhous gastric carcinoma cells have not been defined. The activation of RhoA in several gastric carcinoma cells was examined. The role of RhoA/ROCK pathway in the metastatic processes of gastric carcinoma cells, using a human scirrhous gastric cancer cell line, OCUM-2MD3 was investigated by in vitro adhesion and invasion assay. The effect of ROCK inhibitor, Y-27632 on the mRNA expression of the integrin family and MMP in gastric carcinoma cells was subsequently examined by Reverse transcriptional (RT)-PCR analysis. Finally, Random OCUM-2MD3 cell motility was evaluated using Time-lapse microscopy. ROCK inhibitor significantly increased the adhesion of OCUM-2MD3 cells to the extracellular matrix (ECM) protein matrigel. Further examination using ECM components showed enhanced binding ability was obtained only in laminin and Integrin subunits α3-integrin was clearly up-regulated by treatment with Y-27632 in OCUM-2MD3 cells. ROCK inhibitor also enhanced the invasion of OCUM-2MD3 cells through matrigel and the expression of membrane-type 1 matrix metalloproteinase (MT1-MMP). Time-lapse microscopy showed conversion of OCUM-2MD3 cells from round to more elongated morphology in the presence of Y-27632, suggesting that inhibition of RhoA/ROCK pathway undergo a so-called 'amoeboid to mesenchymal' transition. The fact that Rac1 inhibitor decreased the facilitated invasion by ROCK inhibitor suggested the possibility that increased invasion ability of OCUM-2MD3 cells was related to Rac activity. These data may suggest that RhoA/ROCK regulate plasticity of metastatic gastric carcinoma via mesenchymal-amoeboid transition, leading to provide new insights for designing a new and effective treatment for this type of refractory carcinoma.
authors.affiliation: Department of Surgical Oncology, Osaka City University Graduate School of Medicine, Asahi-machi, Abeno-ku, Japan. tskmtsk@aol.com
authors.forename: Tasuku
authors.initials: T
authors.lastname: Matsuoka
authors.forename: Masakazu
authors.initials: M
authors.lastname: Yashiro
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Kato
authors.forename: Osamu
authors.initials: O
authors.lastname: Shinto
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kashiwagi
authors.forename: Kosei
authors.initials: K
authors.lastname: Hirakawa
mesh_terms: D002293:Adenocarcinoma, Scirrhous / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D016023:Integrins / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured; D054460:rho-Associated Kinases / Q000235:genetics / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D016023:Integrins; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein