title: PI3K/Akt and GSK-3β prevents in a differential fashion the malignant phenotype of colorectal cancer cells.
abstract: OBJECTIVE
  During colorectal cancer progression, the loss of differentiation and cell-cell adhesion as well as a higher migratory potential are well-defined features; however, the signaling mechanism governing these events is not fully elucidated. The aim of this study was to investigate the role that PI3K and downstream effectors play in controlling colon cancer malignant phenotypes.
  
  
  METHODS
  HCT-116 cells, a human model of colon cancer, which are highly metastatic and undifferentiated, were treated with LY294002, a specific inhibitor of PI3K. Cell differentiation and apical junctional complex (AJC) formation were monitored using alkaline phosphatase and electron microscopy analysis. Immunofluorescence and Western blotting were used to accompany the subcellular localization of AJC proteins. PI3K downstream molecules were analyzed by western blotting, and proliferation, wound healing, and colony formation techniques to determine malignant phenotype alterations.
  
  
  RESULTS
  PI3K inhibition increased alkaline phosphatase activity, led to an enterocyte-like growth and formed a functional AJC. LY294002 treatment was able to recruit E-cadherin, β-catenin, claudin-3, and ZO-1 to the cell-cell contact region, and this effect was essential for AJC assembly and association of these proteins to the cytoskeleton. Furthermore, we provided evidence that PI3K inhibition leads to a decrease in p-Akt and p-GSK-3β and increased p-β-catenin levels, which in turn controlled cell proliferation, motility, and colony formation.
  
  
  CONCLUSIONS
  Our results demonstrate that PI3K/Akt and GSK-3β prevents in a differential fashion the malignant phenotype of HCT-116 colorectal cancer cells, which could constitute a potential therapeutic target for treatment of this cancer type.
authors.affiliation: Divisão de Biologia Celular, Instituto Nacional de Câncer, Rio de Janeiro, Rua André Cavalcanti 37, 5° andar, 20230-051 Rio de Janeiro, RJ, Brazil.
authors.forename: Wallace Martins
authors.initials: WM
authors.lastname: de Araújo
authors.forename: Flavia Castello Branco
authors.initials: FC
authors.lastname: Vidal
authors.forename: Waldemir Fernandes
authors.initials: WF
authors.lastname: de Souza
authors.forename: Julio César Madureira
authors.initials: JC
authors.lastname: de Freitas
authors.forename: Wanderley
authors.initials: W
authors.lastname: de Souza
authors.forename: Jose Andres
authors.initials: JA
authors.lastname: Morgado-Diaz
mesh_terms: D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors; D015820:Cadherins / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002867:Chromones / Q000627:therapeutic use*; D003114:Colony-Forming Units Assay; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics / Q000473:pathology*; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D009025:Morpholines / Q000627:therapeutic use*; D010641:Phenotype; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D014945:Wound Healing / Q000187:drug effects; D051176:beta Catenin / Q000378:metabolism
chemical_list: D015820:Cadherins; D002867:Chromones; D004791:Enzyme Inhibitors; D009025:Morpholines; D051176:beta Catenin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D051057:Proto-Oncogene Proteins c-akt; D038362:Glycogen Synthase Kinase 3; D000469:Alkaline Phosphatase