title: The VHL tumor suppressor protein regulates tumorigenicity of U87-derived             glioma stem-like cells by inhibiting the JAK/STAT signaling pathway.
abstract: The signal transducer and activator of transcription 3 (STAT3) factor plays an important role in the tumorigenicity of cancer stem cells. The purpose of this study was to investigate the inhibitory mechanism of this pathway acting through the tumor suppressor von Hippel-Lindau (VHL) protein in glioma cancer stem cells. We isolated floating neurosphere-forming CD133+ cells as glioma stem-like cells (GSLCs) by the MACS method. Furthermore, we examined these cells for their growth rate, ability to form colonies and neurospheres in soft agar, capacity for implantation into SCID mice and expression of CD133, STAT3, JAK2, Elongin A, PTEN and VHL. Furthermore, we transferred the VHL gene, an inhibitor of STAT3, into GSLCs using an adenovirus vector and compared these transfectants with control vector-transfected GSLCs. GSLCs proved to be implantable and formed a tumor in the subcutaneous tissue of SCID mice, the histology of which was similar to that of human glioblastomas. In addition, GSLCs exhibited a high capacity for soft agar colony and neurosphere formation, nearly all of which were CD133 positive. The majority of GSLCs were immunopositive for STAT3, JAK2 and Elongin A, but immunonegative for PTEN and VHL. When the VHL gene was transferred to GSLCs and these cells were transplanted into SCID mice, they did not result in tumor formation. Their capacity for soft agar colony and neurosphere formation was significantly inhibited, although their proliferation was only moderately inhibited. Regarding the expression of various factors, that of CD133 was decreased in the VHL transfectants and those of STAT3, JAK2 and Elongin A were eliminated. However, the expression of PTEN and of VHL was upregulated. These findings suggest that VHL regulated the tumorigenicity and self-renewal ability of glioma cancer stem cells by inhibiting the JAK/STAT signaling pathway.
authors: Department of Neurosurgery, Yokohama City University School of Medicine, Yokohama, Japan. hiroshikannomd@nifty.com
authors: Hiroshi
authors: H
authors: Kanno
authors: Hidemitsu
authors: H
authors: Sato
authors: Taka-Akira
authors: TA
authors: Yokoyama
authors: Tetsuya
authors: T
authors: Yoshizumi
authors: Sachiko
authors: S
authors: Yamada
mesh_terms: D000071916:AC133 Antigen; D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D000075065:Elongin; D018014:Gene Transfer Techniques; D005910:Glioma / Q000235:genetics / Q000378:metabolism*; D006023:Glycoproteins / Q000096:biosynthesis; D006801:Humans; D053614:Janus Kinase 2 / Q000096:biosynthesis; D053612:Janus Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051379:Mice; D016513:Mice, SCID; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D051059:PTEN Phosphohydrolase / Q000096:biosynthesis; D010455:Peptides; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis; D014183:Transplantation, Heterologous; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; C000616397:ELOA protein, human; C000616403:Eloa protein, mouse; D000075065:Elongin; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; C000606024:Prom1 protein, mouse; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D014157:Transcription Factors; D051794:Von Hippel-Lindau Tumor Suppressor Protein; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D053612:Janus Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; C497446:VHL protein, human