title: Enrichment of ovarian cancer stem-like cells is associated with epithelial to mesenchymal transition through an miRNA-activated AKT pathway.
abstract: OBJECTIVE
  Evidence has indicated that ovarian epithelial cancer-type cells under serum-free culture conditions can form spheroid cells and exhibit characteristics expected of cancer stem-like cells (CSCs). However, the mechanism by which differentiated ovarian cancer cells acquire stem-cell properties during CSC enrichment has needed to be elucidated. Recent studies have demonstrated that induction of epithelial to mesenchymal transition (EMT) can generate CSCs and be associated with tumour aggressiveness and metastasis.
  
  
  METHODS
  Ovarian epithelial cancer cell lines, SKOV3 and HO8920, were cultured for spheroid cells and adherent cells. CSC enrichment was investigated using MTT assay, flow cytometery and qRT-PCR and expression level of PI3K/AKT pathway components was analysed by western blotting.
  
  
  RESULTS
  Compared to adherent cells, the spheroid cells expressed mesenchymal markers highly and exhibited significantly more motility; we also observed increases in phosphate AKT1 levels in the spheroid cells. Moreover, transfection of miR-20a or miR-200c led to corresponding reduction in endogenous PTEN protein, while AKT1 and phosphate AKT1 levels were upregulated in miRNAs-transfected cells. Finally, PI3K/AKT pathway inhibitor LY294002 reduced expressions of mesenchymal markers and stem-cell gene activity in spheroid cells, enhancing sensitivity of spheroid cells to paclitaxel treatment.
  
  
  CONCLUSIONS
  Our findings demonstrate that EMT contributed to enrichment of ovarian CSCs in vitro, making EMT targeting in epithelial ovarian cancer a novel therapeutic option.
authors.affiliation: The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: X
authors.initials: X
authors.lastname: Luo
authors.forename: Z
authors.initials: Z
authors.lastname: Dong
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.forename: D
authors.initials: D
authors.lastname: Lai
mesh_terms: D000077216:Carcinoma, Ovarian Epithelial; D002454:Cell Differentiation / Q000502:physiology; D045744:Cell Line, Tumor; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009375:Neoplasms, Glandular and Epithelial / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology*; D010051:Ovarian Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D018874:Spheroids, Cellular
chemical_list: D035683:MicroRNAs; D019869:Phosphatidylinositol 3-Kinases; C494918:AKT1 protein, human; D051057:Proto-Oncogene Proteins c-akt