title: Molecular and cellular characterization of ABCG2 in the prostate.
abstract: BACKGROUND
  Identification and characterization of the prostate stem cell is important for understanding normal prostate development and carcinogenesis. The flow cytometry-based side population (SP) technique has been developed to isolate putative adult stem cells in several human tissue types including the prostate. This phenotype is mainly mediated by the ATP-binding cassette membrane transporter ABCG2.
  
  
  METHODS
  Immunolocalization of ABCG2 was performed on normal prostate tissue obtained from radical prostatectomies. Normal human prostate SP cells and ABCG2+ cells were isolated and gene expression was determined with DNA array analysis and RT-PCR. Endothelial cells were removed by pre-sorting with CD31.
  
  
  RESULTS
  ABCG2 positive cells were localized to the prostate basal epithelium and endothelium. ABCG2+ cells in the basal epithelium constituted less than 1% of the total basal cell population. SP cells constituted 0.5-3% of the total epithelial fraction. The SP transcriptome was essentially the same as ABCG2+ and both populations expressed genes indicative of a stem cell phenotype, however, the cells also expressed many genes in common with endothelial cells.
  
  
  CONCLUSIONS
  These results provide gene expression profiles for the prostate SP and ABCG2+ cells that will be critical for studying normal development and carcinogenesis, in particular as related to the cancer stem cell concept.
authors.affiliation: Department of Urology, and the Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA. pascal2@u.washington.edu
authors.forename: Laura E
authors.initials: LE
authors.lastname: Pascal
authors.forename: Asa J
authors.initials: AJ
authors.lastname: Oudes
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Petersen
authors.forename: Young Ah
authors.initials: YA
authors.lastname: Goo
authors.forename: Laura S
authors.initials: LS
authors.lastname: Walashek
authors.forename: Lawrence D
authors.initials: LD
authors.lastname: True
authors.forename: Alvin Y
authors.initials: AY
authors.lastname: Liu
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000302:isolation & purification*; D002460:Cell Line; D004847:Epithelial Cells; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D009363:Neoplasm Proteins / Q000235:genetics* / Q000302:isolation & purification*; D011467:Prostate / Q000737:chemistry* / Q000166:cytology*; D013234:Stem Cells
chemical_list: C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D009363:Neoplasm Proteins