title: Expansion of CD133-expressing liver cancer stem cells in liver-specific phosphatase and tensin homolog deleted on chromosome 10-deleted mice.
abstract: PTEN (phosphatase and tensin homolog deleted on chromosome 10) is a lipid phosphatase that regulates mitogenic signaling pathways, and deficiency of PTEN results in cell proliferation, survival, and malignancy. Murine liver-specific Pten deletion models develop liver malignancy by 12 months of age. Using this model, we describe a population of CD133+ liver cancer stem cells isolated during the chronic injury phase of disease progression and before primary carcinoma formation. We performed immunohistochemistry and flow cytometry isolation using livers from 3- and 6-month-old Pten(loxP/loxP); Alb-Cre+ mice (mutants) and controls. CD133+CD45- nonparenchymal (NP) cells were analyzed for gene expression profile and protein levels. Single CD133+CD45- oval cells were isolated for clonal expansion and tumor analysis. Cultured and freshly isolated liver CD133+CD45- and CD133-CD45- NP cells were injected into immune-deficient and immune-competent mice. In mutant mice, the NP fraction increased in CD133+CD45- cells in 3- and 6-month-old Pten-deleted animals compared with controls. Clone lines expanded from single CD133+CD45- cells demonstrated consistent liver progenitor cell phenotype, with bilineage gene expression of hepatocyte and cholangiocyte markers. CD133+ cells from expanded clone lines formed robust tumors in immune-deficient and immune-competent mice. Furthermore, freshly isolated CD133+CD45- NP liver cells from 6-month-old mutants formed tumors in vivo, and CD133-CD45- NP cells did not. Consistent with a cancer stem cell phenotype, CD133+ cells demonstrate resistance to chemotherapy agents compared with CD133- cells. CD133+CD45- nonparenchymal cells from chronic injury Pten(loxP/loxP); Alb-Cre+ mice represent a bipotent liver progenitor cell population with cancer stem cell phenotype.
authors.affiliation: Department of Pediatrics, College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania 17033-0850, USA. CRountree@hmc.psu.edu
authors.forename: C Bart
authors.initials: CB
authors.lastname: Rountree
authors.forename: Wei
authors.initials: W
authors.lastname: Ding
authors.forename: Lina
authors.initials: L
authors.lastname: He
authors.forename: Bangyan
authors.initials: B
authors.lastname: Stiles
mesh_terms: D000071916:AC133 Antigen; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D015153:Blotting, Western; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D033481:Chromosomes, Mammalian / Q000235:genetics*; D005434:Flow Cytometry; D006023:Glycoproteins / Q000378:metabolism*; D007150:Immunohistochemistry; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology*; D051379:Mice; D008817:Mice, Mutant Strains; D008819:Mice, Nude; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology; D051059:PTEN Phosphohydrolase / Q000235:genetics*; D010455:Peptides / Q000378:metabolism*; D016133:Polymerase Chain Reaction
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; D010455:Peptides; C000606024:Prom1 protein, mouse; D017493:Leukocyte Common Antigens; D051059:PTEN Phosphohydrolase; C487757:Pten protein, mouse