title: SOX2-RNAi attenuates S-phase entry and induces RhoA-dependent switch to protease-independent amoeboid migration in human glioma cells.
abstract: BACKGROUND
  SOX2, a high mobility group (HMG)-box containing transcription factor, is a key regulator during development of the nervous system and a persistent marker of neural stem cells. Recent studies suggested a role of SOX2 in tumor progression. In our previous work we detected SOX2 in glioma cells and glioblastoma specimens. Herein, we aim to explore the role of SOX2 for glioma malignancy in particular its role in cell proliferation and migration.
  
  
  METHODS
  Retroviral shRNA-vectors were utilized to stably knockdown SOX2 in U343-MG and U373-MG cells. The resulting phenotype was investigated by Western blot, migration/invasion assays, RhoA G-LISA, time lapse video imaging, and orthotopic xenograft experiments.
  
  
  RESULTS
  SOX2 depletion results in pleiotropic effects including attenuated cell proliferation caused by decreased levels of cyclinD1. Also an increased TCF/LEF-signaling and concomitant decrease in Oct4 and Nestin expression was noted. Furthermore, down-regulation of focal adhesion kinase (FAK) signaling and of downstream proteins such as HEF1/NEDD9, matrix metalloproteinases pro-MMP-1 and -2 impaired invasive proteolysis-dependent migration. Yet, cells with knockdown of SOX2 switched to a RhoA-dependent amoeboid-like migration mode which could be blocked by the ROCK inhibitor Y27632 downstream of RhoA-signaling. Orthotopic xenograft experiments revealed a higher tumorigenicity of U343-MG glioma cells transduced with shRNA targeting SOX2 which was characterized by increased dissemination of glioma cells.
  
  
  CONCLUSIONS
  Our findings suggest that SOX2 plays a role in the maintenance of a less differentiated glioma cell phenotype. In addition, the results indicate a critical role of SOX2 in adhesion and migration of malignant gliomas.
authors: Department of Neurosurgery, Section Experimental Neurosurgery and Tumor Immunology, University Hospital Carl Gustav Carus, TU Dresden, Dresden, Fetscherstr 74, 01307 Dresden, Germany.
authors: Felix
authors: F
authors: Oppel
authors: Nadja
authors: N
authors: Müller
authors: Gabriele
authors: G
authors: Schackert
authors: Sandy
authors: S
authors: Hendruschk
authors: Daniel
authors: D
authors: Martin
authors: Kathrin D
authors: KD
authors: Geiger
authors: Achim
authors: A
authors: Temme
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D051417:Focal Adhesion Kinase 1 / Q000235:genetics / Q000378:metabolism; D005910:Glioma / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D051379:Mice; D008815:Mice, Inbred Strains; D009361:Neoplasm Invasiveness / Q000235:genetics; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D016196:S Phase; D055748:SOXB1 Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D023041:Xenograft Model Antitumor Assays; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D034741:RNA, Small Interfering; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors; C066737:RHOA protein, human; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human; D020742:rhoA GTP-Binding Protein