title: Lessons from the first comprehensive molecular characterization of cell cycle control in rodent insulinoma cell lines.
abstract: OBJECTIVE
  Rodent insulinoma cell lines may serve as a model for designing continuously replicating human beta-cell lines and provide clues as to the central cell cycle regulatory molecules in the beta-cell.
  
  
  METHODS
  We performed a comprehensive G1/S proteome analysis on the four most widely studied rodent insulinoma cell lines and defined their flow cytometric profiles and growth characteristics.
  
  
  RESULTS
  1) Despite their common T-antigen-derived origins, MIN6 and BTC3 cells display markedly different G1/S expression profiles; 2) despite their common radiation origins, RINm5F and INS1 cells display striking differences in cell cycle protein profiles; 3) phosphorylation of pRb is absent in INS1 and RINm5F cells; 4) cyclin D2 is absent in RINm5F and BTC3 cells and therefore apparently dispensable for their proliferation; 5) every cell cycle inhibitor is upregulated, presumably in a futile attempt to halt proliferation; 6) among the G1/S proteome members, seven are pro-proliferation molecules: cyclin-dependent kinase-1, -2, -4, and -6 and cyclins A, E, and D3; and 7) overexpression of the combination of these seven converts arrested proliferation rates in primary rat beta-cells to those in insulinoma cells. Unfortunately, this therapeutic overexpression appears to mildly attenuate beta-cell differentiation and function.
  
  
  CONCLUSIONS
  These studies underscore the importance of characterizing the cell cycle at the protein level in rodent insulinoma cell lines. They also emphasize the hazards of interpreting data from rodent insulinoma cell lines as modeling normal cell cycle progression. Most importantly, they provide seven candidate targets for inducing proliferation in human beta-cells.
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania, USA. cozari@dom.pitt.edu
authors.forename: Irene
authors.initials: I
authors.lastname: Cozar-Castellano
authors.forename: George
authors.initials: G
authors.lastname: Harb
authors.forename: Karen
authors.initials: K
authors.lastname: Selk
authors.forename: Karen
authors.initials: K
authors.lastname: Takane
authors.forename: Rupangi
authors.initials: R
authors.lastname: Vasavada
authors.forename: Brian
authors.initials: B
authors.lastname: Sicari
authors.forename: Brian
authors.initials: B
authors.lastname: Law
authors.forename: Pili
authors.initials: P
authors.lastname: Zhang
authors.forename: Donald K
authors.initials: DK
authors.lastname: Scott
authors.forename: Nathalie
authors.initials: N
authors.lastname: Fiaschi-Taesch
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Stewart
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D019925:Cyclin A / Q000235:genetics / Q000378:metabolism; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism; D019927:Cyclin E / Q000235:genetics / Q000378:metabolism; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism; D005434:Flow Cytometry; D016193:G1 Phase; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000378:metabolism*; D007340:Insulinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016196:S Phase; D014162:Transfection
chemical_list: D019925:Cyclin A; D019927:Cyclin E; D019938:Cyclin D1; D018844:Cyclin-Dependent Kinases