title: Plastic induction of CD133AC133-positive cells in the microenvironment of glioblastoma spheroids.
abstract: Recent studies showed that the stemness of cancer stem cells is maintained under a hypoxic microenvironment. However, the relationship of the hypoxic microenvironment in a three-dimensional cell mass and the induction of cancer stem cell-like phenotype is not well known. We examined the relationship between CD133 expression and the hypoxic microenvironment using glioblastoma spheroids formed with the T98G cell line. CD133(AC133)- and HIF-1α-positive cells were observed in the marginal region of the central hypoxic area positive for HIF-1α 10 days after plating T98G cells. CD133(AC133)-positive cells were positive for nestin. Quantitative PCR analysis showed that the CD133 expression level is not different in spheroids during the tested period after spheroid formation, indicating that post-translational regulation of the CD133 protein mediates positivity to CD133(AC133). When spheroids were trypsinized and the dissociated cells were cultured under the adherent monolayer conditions, the CD133(AC133)-positive cells gradually disappeared. These results show that CD133(AC133)-positive cells, which may incline toward undifferentiated cells because of nestin positivity, are plastically induced under the different culture conditions, spheroid and monolayer. In this plasticity, HIF-1α is involved in the induction and maintenance of CD133(AC133)-positive cells. Spheroids as an in vitro tumor model are useful to study the dynamic changes in the tumor cell phenotype in the different cell microenvironments.
authors.affiliation: Department of Biology, Center for Humanity and Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki-gun, Ibaraki 300-0394, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Ohnishi
authors.affiliation: Department of Biology, Center for Humanity and Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki-gun, Ibaraki 300-0394, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tani
authors.affiliation: Department of Biology, Center for Humanity and Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki-gun, Ibaraki 300-0394, Japan.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Bando
authors.affiliation: Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki-gun, Ibaraki 300-0394, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kubota
authors.affiliation: Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki-gun, Ibaraki 300-0394, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Fujii
authors.affiliation: Department of Anatomy, Nara Medical University, Kashihara, Nara 634-8521, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Hatano
authors.affiliation: Group of Radiation and Tumor Biology, Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Yoshida-Konoe-Cho, Sakyo-ku 606-8501, Japan.
authors.forename: Hirosi
authors.initials: H
authors.lastname: Harada
mesh_terms: D000071916:AC133 Antigen; D015703:Antigens, CD / Q000378:metabolism*; D015687:Cell Hypoxia / Q000502:physiology; D045744:Cell Line, Tumor; D005455:Fluorescent Antibody Technique; D005909:Glioblastoma / Q000378:metabolism / Q000473:pathology*; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology*; D010455:Peptides / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D018874:Spheroids, Cellular / Q000378:metabolism / Q000473:pathology*; D014162:Transfection; D059016:Tumor Microenvironment / Q000502:physiology*
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides