title: [Epithelial-mesenchymal transition of prostate cancer: cancer stem cells or bulk cancer cells].
abstract: OBJECTIVE
  To test the hypothesis that epithelial-mesenchymal transition (EMT) of prostate cancer is most likely to occur in cancer stem cells (CSC).
  
  
  METHODS
  The isolation of CSC from LNCaP cell line was performed by flow cytometry based on side-population (SP) phenotype. After SP sorting, LNCaP/SP and LNCaP/NSP were used for further transfection of hypoxia-inducible factor-1α (HIF-1α). Subsequently, EMT-associated proteins were detected by Western blotting. And the assays of Transwell and methyl thiazolyl tetrazolium (MTT) were used to compare invasive and proliferative potency between LNCaP/SP and LNCaP/NSP after HIF-1α induction. Eventually, xenograft experiments were performed with LNCaP/HIF-1α/SP and LNCaP/HIF-1α/NSP cells for further analysis of in vivo tumorigenesis and distant metastasis.
  
  
  RESULTS
  Through HIF-1α-induced EMT, LNCaP/HIF-1α/SP exhibited such remarkable EMT characteristics as a positive expression of epithelial markers (E-cadherin and CK18) and a negative expression of mesenchymal markers (vimentin, N-cadherin, fibronectin, cathepsin D, MMP-2 and uPAR). And LNCaP/HIF-1α/NSP underwent partial EMT with an abnormal expression of some mesenchymal proteins (vimentin and cathepsin D) and loss of epithelial protein (CK18) despite reservation of another important epithelial marker (E-cadherin). Further Transwell and MTT assays indicated that LNCaP/HIF-1α/SP exhibited stronger in vitro invasive and proliferative potency than LNCaP/HIF-1α/NSP cells. In animal models, the volume of subcutaneous tumor by LNCaP/HIF-1α/SP cells was much greater than that by LNCaP/HIF-1α/NSP counterparts ((1008 ± 230) vs (288 ± 145) mm(3), P < 0.01). Moreover, LNCaP/HIF-1α/SP cells also had a significantly higher rate of subcutaneous tumor incidence (80% vs 53%, P < 0.05) and bone metastasis (40% vs 0, P < 0.01) as compared with LNCaP/HIF-1α/NSP counterparts.
  
  
  CONCLUSIONS
  As the main target cells of prostatic EMT, CSCs may develop a more malignant phenotype after EMT.
authors.affiliation: Department of Urology, Affiliated Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China. luoyonganzhen@sohu.com
authors.forename: Yong
authors.initials: Y
authors.lastname: Luo
authors.forename: Xin-hao
authors.initials: XH
authors.lastname: Cui
authors.forename: Yong-guang
authors.initials: YG
authors.lastname: Jiang
authors.forename: Da-lin
authors.initials: DL
authors.lastname: He
authors.forename: Jia-hui
authors.initials: JH
authors.lastname: Zhao
authors.forename: Lin
authors.initials: L
authors.lastname: Zhao
authors.forename: Ya-tong
authors.initials: YT
authors.lastname: Chen
authors.forename: Ming-chuan
authors.initials: MC
authors.lastname: Li
authors.forename: Yun-hua
authors.initials: YH
authors.lastname: Lin
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D018076:DNA, Complementary; D058750:Epithelial-Mesenchymal Transition; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics*; D008297:Male; D009361:Neoplasm Invasiveness; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000166:cytology* / Q000473:pathology; D058985:Side-Population Cells / Q000166:cytology* / Q000473:pathology; D014162:Transfection
chemical_list: D018076:DNA, Complementary; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit