title: Long-term controlled immortalization of a primate hepatic progenitor cell line after Simian virus 40 T-Antigen gene transfer.
abstract: Hepatoblasts are bipotent progenitors of both hepatocytes and cholangiocytes. The lack of stable in vitro culture systems for such cells makes it necessary to generate liver progenitor cell lines by means of immortalization. In this study, we describe the long-term behaviour of a clone of simian foetal hepatic progenitor cells immortalized by Simian virus 40 (SV40) large T-antigen (T-Ag) flanked by loxP sites. Immortalization was associated with the re-expression of telomerase activity, which decreased at late passages (population doubling 120) after more than a year in culture. This decrease was concomitant to telomere shortening and karyotypic instability. However, the chromosomes carrying the p53 gene remained intact and long-term immortalized progenitor cells maintained contact inhibition and proliferative properties. They also displayed the features of a normal bipotent phenotype. We constructed a retroviral vector expressing an inducible Cre recombinase and transferred it into the immortalized progenitors. Activation of the Cre recombinase by 4-hydroxy-tamoxifen induced SV40 T-Ag excision, leading to the death of cells expressing Cre recombinase. Immortalized progenitors at late passages stopped growing and eventually disappeared after transplantation into the livers of immunocompromised mice. These cells provide a novel model to study hepatic differentiation and carcinogenesis.
authors.affiliation: INSERM EMI 00-20; University Paris XI, Hôpital Kremlin-Bicêtre, 80 avenue du Général Leclerc, 94276 Kremlin-Bicêtre, France.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Delgado
authors.forename: Alexandre
authors.initials: A
authors.lastname: Parouchev
authors.forename: Jean-Etienne
authors.initials: JE
authors.lastname: Allain
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Pennarun
authors.forename: Laurent R
authors.initials: LR
authors.lastname: Gauthier
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Dutrillaux
authors.forename: Bernard
authors.initials: B
authors.lastname: Dutrillaux
authors.forename: James
authors.initials: J
authors.lastname: Di Santo
authors.forename: Frédérique
authors.initials: F
authors.lastname: Capron
authors.forename: François D
authors.initials: FD
authors.lastname: Boussin
authors.forename: Anne
authors.initials: A
authors.lastname: Weber
mesh_terms: D000818:Animals; D000957:Antigens, Viral, Tumor / Q000235:genetics* / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D002461:Cell Line, Transformed; D049109:Cell Proliferation; D002478:Cells, Cultured; D033481:Chromosomes, Mammalian / Q000378:metabolism; D000882:Haplorhini; D022781:Hepatocytes / Q000166:cytology* / Q000378:metabolism*; D007621:Karyotyping; D051379:Mice; D018345:Mice, Knockout; D013539:Simian virus 40 / Q000235:genetics*; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*; D019098:Telomerase / Q000378:metabolism; D016615:Telomere / Q000378:metabolism; D013997:Time Factors
chemical_list: D000957:Antigens, Viral, Tumor; D018797:Cell Cycle Proteins; D019098:Telomerase