title: ALDH maintains the stemness of lung adenoma stem cells by suppressing the Notch/CDK2/CCNE pathway.
abstract: OBJECTIVE
  To evaluate the expression of ALDH1A1 in lung adenoma stem cells (LASCs) and maintenance of their stemness through the Notch pathway.
  
  
  METHODS
  LASCs (A549s) were isolated from lung adenoma cells (A549) and identified by their coexpression of CD133 and CD326 and their capacity formulti-directional differentiation. Expression of ALDH1A1 in A549 and A549s cells were evaluated by Real-time PCR. Effects of ALDH1A1 upregulation in A549 cells and its downregulation in A549s cells on the clonogenicity and cell cycle were assessed by colony-forming unit assay. Moreover, the effects of ALDH1A1 on the Notch pathway, and thus on the cell cycle, were studied.
  
  
  RESULTS
  A549s cells were successfully isolated and identified.ALDH1A1expression was significantly higher in A549s than in A549 cells. Clonogenicity was significantly decreased in A549s cells treated with ALDH1A1 siRNA. Duration of the G1 stage of the cell cycle increased after ALDH1A1 was overexpressed, or decreased with ALDH1A1 siRNA. ALDH1A1, Notch1, -2, and -3, CDK2, and CCNE1 expression levels were higher in A549s cells than in A549 cells. Expression of Notch1, -2, and -3, CDK2, and CCNE1 was significantly decreased by upregulation of ALDH1A1 in A549 cells, but increased by its interruption in A549s cells. When Notch3 or CDK2 expression was downregulated, the expression levels of ALDH1A1, Notch1, -2, and -3, CDK2, and CCNE1 were reduced in all cell types.
  
  
  CONCLUSIONS
  ALDH1A1 expression improved clonogenicity and inhibited the cell cycle, maintaining the stemness of the A549s cells; this may involve suppression of the Notch/CDK2/Cyclin pathway.
authors.affiliation: Department of Blood Transfusion, The Second Affiliated Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Zhongjun
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Blood Transfusion, The Second Affiliated Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xiang
authors.affiliation: Department of Blood Transfusion, The Second Affiliated Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Xiang
authors.affiliation: Department of Blood Transfusion, The Second Affiliated Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Yanni
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: Department of Blood Transfusion, The Second Affiliated Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Fengjie
authors.initials: F
authors.lastname: Li
authors.affiliation: Department of Oncology, The Second Affiliated Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Hao
mesh_terms: D000236:Adenoma / Q000378:metabolism* / Q000473:pathology; D000444:Aldehyde Dehydrogenase / Q000378:metabolism*; D000080924:Aldehyde Dehydrogenase 1 Family; D002453:Cell Cycle; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D002469:Cell Separation; D002999:Clone Cells; D019927:Cyclin E / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2 / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology*; D015513:Oncogene Proteins / Q000378:metabolism*; D051880:Receptors, Notch / Q000378:metabolism*; D050697:Retinal Dehydrogenase; D015398:Signal Transduction
chemical_list: C475820:CCNE1 protein, human; D019927:Cyclin E; D015513:Oncogene Proteins; D051880:Receptors, Notch; D000080924:Aldehyde Dehydrogenase 1 Family; D000444:Aldehyde Dehydrogenase; C510223:ALDH1A1 protein, human; D050697:Retinal Dehydrogenase; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2