title: An off-target nucleostemin RNAi inhibits growth in human glioblastoma-derived cancer stem cells.
abstract: Glioblastomas (GBM) may contain a variable proportion of active cancer stem cells (CSCs) capable of self-renewal, of aggregating into CD133(+) neurospheres, and to develop intracranial tumors that phenocopy the original ones. We hypothesized that nucleostemin may contribute to cancer stem cell biology as these cells share characteristics with normal stem cells. Here we report that nucleostemin is expressed in GBM-CSCs isolated from patient samples, and that its expression, conversely to what it has been described for ordinary stem cells, does not disappear when cells are differentiated. The significance of nucleostemin expression in CSCs was addressed by targeting the corresponding mRNA using lentivirally transduced short hairpin RNA (shRNA). In doing so, we found an off-target nucleostemin RNAi (shRNA22) that abolishes proliferation and induces apoptosis in GBM-CSCs. Furthermore, in the presence of shRNA22, GBM-CSCs failed to form neurospheres in vitro or grow on soft agar. When these cells are xenotransplanted into the brains of nude rats, tumor development is significantly delayed. Attempts were made to identify the primary target/s of shRNA22, suggesting a transcription factor involved in one of the MAP-kinases signaling-pathways or multiple targets. The use of this shRNA may contribute to develop new therapeutic approaches for this incurable type of brain tumor.
authors.affiliation: Departamento de Biología Molecular, Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Instituto Sanitario Ramón y Cajal, Madrid, Spain.
authors.forename: Jon
authors.initials: J
authors.lastname: Gil-Ranedo
authors.forename: Marina
authors.initials: M
authors.lastname: Mendiburu-Eliçabe
authors.forename: Mercedes
authors.initials: M
authors.lastname: García-Villanueva
authors.forename: Diego
authors.initials: D
authors.lastname: Medina
authors.forename: Marta
authors.initials: M
authors.lastname: del Álamo
authors.forename: Marta
authors.initials: M
authors.lastname: Izquierdo
mesh_terms: D000071916:AC133 Antigen; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D017209:Apoptosis; D002449:Cell Aggregation; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000235:genetics / Q000473:pathology*; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D011923:Rats, Nude
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; C469949:GNL3 protein, human; D006023:Glycoproteins; D009687:Nuclear Proteins; C000606023:PROM1 protein, human; D010455:Peptides; C000606025:Prom1 protein, rat; D034741:RNA, Small Interfering; D019204:GTP-Binding Proteins