title: Epithelial-mesenchymal transition and mesenchymal-epithelial transition are essential for the acquisition of stem cell properties in hTERT-immortalised oral epithelial cells.
abstract: BACKGROUND
  Evidence has shown that mesenchymal-epithelial transition (MET) and epithelial-mesenchymal transition (EMT) are linked to stem cell properties. We currently lack a model showing how the occurrence of MET and EMT in immortalised cells influences the maintenance of stem cell properties. Thus, we established a project aiming to investigate the roles of EMT and MET in the acquisition of stem cell properties in immortalised oral epithelial cells.
  
  
  RESULTS
  In this study, a retroviral transfection vector (pLXSN-hTERT) was used to immortalise oral epithelial cells by insertion of the hTERT gene (hTERT(+)-oral mucosal epithelial cell line [OME]). The protein and RNA expression of EMT transcriptional factors (Snail, Slug and Twist), their downstream markers (E-cadherin and N-cadherin) and embryonic stem cell markers (OCT4, Nanog and Sox2) were studied by reverse transcription PCR and Western blots in these cells. Some EMT markers were detected at both mRNA and protein levels. Adipocytes and bone cells were noted in the multi-differentiation assay, showing that the immortal cells underwent EMT. The differentiation assay for hTERT(+)-OME cells revealed the recovery of epithelial phenotypes, implicating the presence of MET. The stem cell properties were confirmed by the detection of appropriate markers. Altered expression of α-tubulin and γ-tubulin in both two-dimensional-cultured (without serum) and three-dimensional-cultured hTERT(+)-OME spheroids indicated the re-programming of cytoskeleton proteins which is attributed to MET processes in hTERT(+)-OME cells.
  
  
  CONCLUSIONS
  EMT and MET are essential for hTERT-immortalised cells to maintain their epithelial stem cell properties.
authors.affiliation: Cancer Molecular Pathology, Griffith Medical School and Griffith Health Institute, Gold Coast, Queensland 4222, Australia.
authors.forename: Bin
authors.initials: B
authors.lastname: Qiao
authors.forename: Vinod
authors.initials: V
authors.lastname: Gopalan
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Chen
authors.forename: Robert Anthony
authors.initials: RA
authors.lastname: Smith
authors.forename: Qian
authors.initials: Q
authors.lastname: Tao
authors.forename: Alfred King-yin
authors.initials: AK
authors.lastname: Lam
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D001842:Bone and Bones / Q000166:cytology / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000032:analysis / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D058750:Epithelial-Mesenchymal Transition; D006801:Humans; D009061:Mouth Mucosa / Q000166:cytology / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D019098:Telomerase / Q000235:genetics / Q000378:metabolism
chemical_list: D003598:Cytoskeletal Proteins; C509186:TERT protein, human; D019098:Telomerase