title: Immortalization of human fetal cells: the life span of umbilical cord blood-derived cells can be prolonged without manipulating p16INK4a/RB braking pathway.
abstract: Human umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) are expected to serve as an excellent alternative to bone marrow-derived human mesenchymal stem cells. However, it is difficult to study them because of their limited life span. To overcome this problem, we attempted to produce a strain of UCBMSCs with a long life span and to investigate whether the strain could maintain phenotypes in vitro. UCBMSCs were infected with retrovirus carrying the human telomerase reverse transcriptase (hTERT) to prolong their life span. The UCBMSCs underwent 30 population doublings (PDs) and stopped dividing at PD 37. The UCBMSCs newly established with hTERT (UCBTERTs) proliferated for >120 PDs. The p16INK4a/RB braking pathway leading to senescence can be inhibited by introduction of Bmi-1, a polycomb-group gene, and human papillomavirus type 16 E7, but the extension of the life span of the UCBMSCs with hTERT did not require inhibition of the p16INK4a/RB pathway. The characteristics of the UCBTERTs remained unchanged during the prolongation of life span. UCBTERTs provide a powerful model for further study of cellular senescence and for future application to cell-based therapy by using umbilical cord blood cells.
authors.affiliation: Department of Reproductive Biology and Pathology, National Research Institute for Child Health and Development, Tokyo 157-8535, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Terai
authors.forename: Taro
authors.initials: T
authors.lastname: Uyama
authors.forename: Tadashi
authors.initials: T
authors.lastname: Sugiki
authors.forename: Xiao-Kang
authors.initials: XK
authors.lastname: Li
authors.forename: Akihiro
authors.initials: A
authors.lastname: Umezawa
authors.forename: Tohru
authors.initials: T
authors.lastname: Kiyono
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D018929:Cell Culture Techniques / Q000379:methods*; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D017690:Cell Transplantation; D002478:Cells, Cultured / Q000166:cytology*; D016922:Cellular Senescence; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism*; D004268:DNA-Binding Proteins; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D006801:Humans; D007621:Karyotyping; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009687:Nuclear Proteins / Q000378:metabolism; D009856:Oncogene Proteins, Viral / Q000378:metabolism; D010011:Osteocytes / Q000166:cytology; D050725:Papillomavirus E7 Proteins; D010641:Phenotype; D063150:Polycomb Repressive Complex 1; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000378:metabolism*; D012190:Retroviridae / Q000235:genetics; D013234:Stem Cells / Q000166:cytology; D019098:Telomerase / Q000378:metabolism; D016615:Telomere / Q000378:metabolism / Q000648:ultrastructure; D013997:Time Factors
chemical_list: C069077:BMI1 protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D016160:Retinoblastoma Protein; C059731:oncogene protein E7, Human papillomavirus type 16; D063150:Polycomb Repressive Complex 1; D019098:Telomerase