title: Elimination of proliferating cells from CNS grafts using a Ki67 promoter-driven thymidine kinase.
abstract: Pluripotent stem cell (PSC)-based cell therapy is an attractive concept for neurodegenerative diseases, but can lead to tumor formation. This is particularly relevant as proliferating neural precursors rather than postmitotic mature neurons need to be transplanted. Thus, safety mechanisms to eliminate proliferating cells are needed. Here, we propose a suicide gene approach, based on cell cycle-dependent promoter Ki67-driven expression of herpes simplex virus thymidine kinase (HSV-TK). We generated a PSC line expressing this construct and induced neural differentiation. In vitro, proliferating PSC and early neural precursor cells (NPC) were killed by exposure to ganciclovir.In vivo, transplantation of PSC led to tumor formation, which was prevented by early ganciclovir treatment. Transplanted NPC did not lead to tumor formation and their survival and neural maturation were not affected by ganciclovir. In conclusion, the cell cycle promoter-driven suicide gene approach described in this study allows killing of proliferating undifferentiated precursor cells without expression of the suicide gene in mature neurons. This approach could also be of use for other stem cell-based therapies where the final target consists of postmitotic cells.
authors.affiliation: Department of pathology and immunology, Geneva medical school, University of Geneva, Geneva, Switzerland; Department of genetic medicine and laboratory, Geneva Hospitals, Geneva, Switzerland.
authors.forename: Vannary
authors.initials: V
authors.lastname: Tieng
authors.affiliation: Department of pathology and immunology, Geneva medical school, University of Geneva , Geneva, Switzerland.
authors.forename: Ophelie
authors.initials: O
authors.lastname: Cherpin
authors.affiliation: Department of pathology and immunology, Geneva medical school, University of Geneva , Geneva, Switzerland.
authors.forename: Eveline
authors.initials: E
authors.lastname: Gutzwiller
authors.affiliation: Department of Biopharmaceutical Science, Keck Graduate Institute , Claremont, California, USA.
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Zambon
authors.affiliation: Department of pathology and immunology, Geneva medical school, University of Geneva , Geneva, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Delgado
authors.affiliation: Department of basic neurosciences, Geneva medical school, University of Geneva , Geneva, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Salmon
authors.affiliation: Department of pathology and immunology, Geneva medical school, University of Geneva , Geneva, Switzerland.
authors.forename: Michel
authors.initials: M
authors.lastname: Dubois-Dauphin
authors.affiliation: Department of pathology and immunology, Geneva medical school, University of Geneva, Geneva, Switzerland; Department of genetic medicine and laboratory, Geneva Hospitals, Geneva, Switzerland.
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Krause