title: PI3K/Akt and Stat3 signaling regulated by PTEN control of the cancer             stem cell population, proliferation and senescence in a glioblastoma cell line.
abstract: Malignant gliomas are the most common primary brain tumor in adults. A number of genes have been implicated in glioblastoma including mutation and deletion of PTEN. PTEN is a regulator of PI3K-mediated Akt signaling pathways and has been recognized as a therapeutic target in glioblastoma. To achieve potent therapeutic inhibition of the PI3K-Akt pathway in glioblastoma, it is essential to understand the interplay between the regulators of its activation. Here, ectopic expression of PTEN in the U-87MG human glioblastoma-astrocytoma cell line is shown to result in the depletion of glioblastoma stem cells (GSCs) and to cause growth retardation and senescence. These effects are likely to be associated with PTEN-mediated cooperative perturbation of Akt and Stat3 signals. Using an in vivo rat model of glioblastoma, we showed that PTEN-overexpressing U-87MG cells failed to induce tumor formation, while untreated U-87MG cells did so. Furthermore, cells expressing the phosphorylated form of Stat3 were completely absent from the brain of rats implanted with PTEN-overexpressing U-87MG cells. Based on these results, PTEN appears to function as a crucial inhibitor of GSCs and as an inducer of senescence, suggesting that functional enhancement of the PTEN pathway will be useful to provide a therapeutic strategy for targeting glioblastoma.
authors: Department of Biomedical Science, College of Life Science, CHA                     University, Seoul, Republic of Korea.
authors: Seok-Ho
authors: SH
authors: Moon
authors: Dae-Kwan
authors: DK
authors: Kim
authors: Young
authors: Y
authors: Cha
authors: Iksoo
authors: I
authors: Jeon
authors: Jihwan
authors: J
authors: Song
authors: Kyung-Soon
authors: KS
authors: Park
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D016922:Cellular Senescence; D005909:Glioblastoma / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D008297:Male; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000502:physiology*; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction; D023041:Xenograft Model Antitumor Assays
chemical_list: D018129:Phosphatidylinositol Phosphates; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C060974:phosphatidylinositol 3,4,5-triphosphate; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human