title: Genomic instability of human embryonic stem cell lines using different passaging culture methods.
abstract: BACKGROUND
  Human embryonic stem cells exhibit genomic instability that can be related to culture duration or to the passaging methods used for cell dissociation. In order to study the impact of cell dissociation techniques on human embryonic stem cells genomic instability, we cultured H1 and H9 human embryonic stem cells lines using mechanical/manual or enzymatic/collagenase-IV dissociation methods. Genomic instability was evaluated at early (<p60) and late (>p60) passages by using oligonucleotide based array-comparative genomic hybridization 105 K with a mean resolution of 50 Kb.
  
  
  RESULTS
  DNA variations were mainly located on subtelomeric and pericentromeric regions with sizes <100 Kb. In this study, 9 recurrent genomic variations were acquired during culture including the well known duplication 20q11.21. When comparing cell dissociation methods, we found no significant differences between DNA variations number and size, DNA gain or DNA loss frequencies, homozygous loss frequencies and no significant difference on the content of genes involved in development, cell cycle tumorigenesis and syndrome disease. In addition, we have never found any malignant tissue in 4 different teratoma representative of the two independent stem cell lines.
  
  
  CONCLUSIONS
  These results show that the occurrence of genomic instability in human embryonic stem cells is similar using mechanical or collagenase IV-based enzymatic cell culture dissociation methods. All the observed genomic variations have no impact on the development of malignancy.
authors.affiliation: AP-HP, Histologie-Embryologie-Cytogénétique, Hôpitaux Universitaires Paris Sud, Clamart, F-92141 France ; Université Paris Sud, Le Kremlin-Bicêtre, F-94275 France ; Esteam Paris Sud INSERM UMR-S 935, Villejuif, F-94801 France.
authors.forename: Lucie
authors.initials: L
authors.lastname: Tosca
authors.affiliation: Esteam Paris Sud INSERM UMR-S 935, Villejuif, F-94801 France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Feraud
authors.affiliation: Esteam Paris Sud INSERM UMR-S 935, Villejuif, F-94801 France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Magniez
authors.affiliation: AP-HP, Histologie-Embryologie-Cytogénétique, Hôpitaux Universitaires Paris Sud, Clamart, F-92141 France ; Esteam Paris Sud INSERM UMR-S 935, Villejuif, F-94801 France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Bas
authors.affiliation: Esteam Paris Sud INSERM UMR-S 935, Villejuif, F-94801 France ; Université Paris Descartes, Sorbonne Paris Cité, F-75006 France.
authors.forename: Frank
authors.initials: F
authors.lastname: Griscelli
authors.affiliation: Université Paris Sud, Le Kremlin-Bicêtre, F-94275 France ; Esteam Paris Sud INSERM UMR-S 935, Villejuif, F-94801 France ; AP-HP, Hématologie, Hôpitaux Universitaires Paris Sud, Villejuif, F-94801 France.
authors.forename: Annelise
authors.initials: A
authors.lastname: Bennaceur-Griscelli
authors.affiliation: AP-HP, Histologie-Embryologie-Cytogénétique, Hôpitaux Universitaires Paris Sud, Clamart, F-92141 France ; Université Paris Sud, Le Kremlin-Bicêtre, F-94275 France ; Esteam Paris Sud INSERM UMR-S 935, Villejuif, F-94801 France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Tachdjian
keywords: Array-CGH; Cell passaging methods; Collagenase IV; Genomic instability; Human embryonic stem cells