title: Activation of β-catenin and Akt pathways by Twist are critical for the maintenance of EMT associated cancer stem cell-like characters.
abstract: BACKGROUND
  Epithelial-mesenchymal transition (EMT) not only confers tumor cells with a distinct advantage for metastatic dissemination, but also it provides those cells with cancer stem cell-like characters for proliferation and drug resistance. However, the molecular mechanism for maintenance of these stem cell-like traits remains unclear.
  
  
  METHODS
  In this study, we induced EMT in breast cancer MCF7 and cervical cancer Hela cells with expression of Twist, a key transcriptional factor of EMT. The morphological changes associated with EMT were analyzed by immunofluorescent staining and Western blotting. The stem cell-like traits associated with EMT were determined by tumorsphere-formation and expression of ALDH1 and CD44 in these cells. The activation of β-catenin and Akt pathways was examined by Western blotting and luciferase assays.
  
  
  RESULTS
  We found that expression of Twist induced a morphological change associated with EMT. We also found that the cancer stem cell-like traits, such as tumorsphere formation, expression of ALDH1 and CD44, were significantly elevated in Twist-overexpressing cells. Interestingly, we showed that β-catenin and Akt pathways were activated in these Twist-overexpressing cells. Activation of β-catenin correlated with the expression of CD44. Knockdown of β-catenin expression and inhibition of the Akt pathway greatly suppressed the expression of CD44.
  
  
  CONCLUSIONS
  Our results indicate that activation of β-catenin and Akt pathways are required for the sustention of EMT-associated stem cell-like traits.
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky School of Medicine, Lexington, KY 40506, USA.
authors.forename: Junlin
authors.initials: J
authors.lastname: Li
authors.forename: Binhua P
authors.initials: BP
authors.lastname: Zhou
mesh_terms: D000080924:Aldehyde Dehydrogenase 1 Family; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism*; D034622:RNA Interference; D050697:Retinal Dehydrogenase / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D051879:Twist-Related Protein 1 / Q000235:genetics / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism; D060508:Wnt3 Protein; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*
chemical_list: D018960:Hyaluronan Receptors; D007527:Isoenzymes; D009687:Nuclear Proteins; C103173:TWIST1 protein, human; D051879:Twist-Related Protein 1; D051153:Wnt Proteins; D060508:Wnt3 Protein; D051176:beta Catenin; D000080924:Aldehyde Dehydrogenase 1 Family; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase; D051057:Proto-Oncogene Proteins c-akt