title: SPARC Expression Is Selectively Suppressed in Tumor Initiating Urospheres Isolated from As+3- and Cd+2-Transformed Human Urothelial Cells (UROtsa) Stably Transfected with SPARC.
abstract: BACKGROUND
  This laboratory previously analyzed the expression of SPARC in the parental UROtsa cells, their arsenite (As(+3)) and cadmium (Cd(+2))-transformed cell lines, and tumor transplants generated from the transformed cells. It was demonstrated that SPARC expression was down-regulated to background levels in Cd(+2)-and As(+3)-transformed UROtsa cells and tumor transplants compared to parental cells. In the present study, the transformed cell lines were stably transfected with a SPARC expression vector to determine the effect of SPARC expression on the ability of the cells to form tumors in immune-compromised mice.
  
  
  METHODS
  Real time PCR, western blotting, immunohistochemistry, and immunofluorescence were used to define the expression of SPARC in the As(+3)-and Cd(+2)-transformed cell lines, and urospheres isolated from these cell lines, following their stable transfection with an expression vector containing the SPARC open reading frame (ORF). Transplantation of the cultured cells into immune-compromised mice by subcutaneous injection was used to assess the effect of SPARC expression on tumors generated from the above cell lines and urospheres.
  
  
  RESULTS
  It was shown that the As(+3)-and Cd(+2)-transformed UROtsa cells could undergo stable transfection with a SPARC expression vector and that the transfected cells expressed both SPARC mRNA and secreted protein. Tumors formed from these SPARC-transfected cells were shown to have no expression of SPARC. Urospheres isolated from cultures of the SPARC-transfected As(+3)-and Cd(+2)-transformed cell lines were shown to have only background expression of SPARC. Urospheres from both the non-transfected and SPARC-transfected cell lines were tumorigenic and thus fit the definition for a population of tumor initiating cells.
  
  
  CONCLUSIONS
  Tumor initiating cells isolated from SPARC-transfected As(+3)-and Cd(+2)-transformed cell lines have an inherent mechanism to suppress the expression of SPARC mRNA.
authors.affiliation: Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, United States of America.|Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, United States of America.
authors.forename: Andrea
authors.initials: A
authors.lastname: Slusser-Nore
authors.affiliation: Department of Medicine, Division of Pulmonary, Allergy and Critical Medicine, the University of Alabama at Birmingham, Birmingham, Alabama, United States of America.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Larson-Casey
authors.affiliation: Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, United States of America.
authors.forename: Ruowen
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, United States of America.
authors.forename: Xu Dong
authors.initials: XD
authors.lastname: Zhou
authors.affiliation: Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, United States of America.
authors.forename: Seema
authors.initials: S
authors.lastname: Somji
authors.affiliation: Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, United States of America.
authors.forename: Scott H
authors.initials: SH
authors.lastname: Garrett
authors.affiliation: Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, United States of America.
authors.forename: Donald A
authors.initials: DA
authors.lastname: Sens
authors.affiliation: Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, North Dakota, United States of America.
authors.forename: Jane R
authors.initials: JR
authors.lastname: Dunlevy
mesh_terms: D000818:Animals; D018053:Arsenites / Q000633:toxicity*; D002104:Cadmium / Q000633:toxicity*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced; D015536:Down-Regulation; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D051379:Mice; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D015676:Osteonectin / Q000235:genetics / Q000378:metabolism*; D019459:Urothelium / Q000166:cytology / Q000187:drug effects
chemical_list: D018053:Arsenites; D015676:Osteonectin; C577241:SPARC protein, human; D002104:Cadmium; C015001:arsenite