title: PTEN gene transfer suppresses the invasive potential of human malignant gliomas by regulating cell invasion-related molecules.
abstract: Loss of function of the tumor suppressor gene PTEN is more frequently encountered in high-grade malignant gliomas than in low-grade gliomas. High-grade gliomas are characterized by their extremely invasive behavior, suggesting that PTEN is one of the important regulators of cell motility and that alterations of its coding gene contribute to a much more invasive tumor cell phenotype. In order to clarify a role of PTEN in glioma invasion, we introduced the wild-type PTEN gene into human malignant glioma cell lines and investigated their motile and invasive activity in a brain slice model that presents circumstances analogous to normal brain conditions in vivo. In addition, we analyzed biochemical and molecular changes resulting from the transfer of PTEN in the glioma cells. Infection of recombinant replication-defective adenovirus vector containing the wild-type PTEN cDNA (Ad5CMV-PTEN) significantly inhibited the cell migration and invasion activities of PTEN-mutated glioma cell lines in in vitro migration and chemoinvasion assays. In an organotypic brain slice model, co-culture of glioma spheroids and rat brain slices demonstrated that Ad5CMV-PTEN transfected cells failed to invade surrounding normal brain tissues. Ad5CMV-PTEN transfer into the glioma cell lines lacking the wild-type gene product decreased the levels of matrix metalloproteinase (MMP)-2 mRNA and inhibited the enzymatic activities of MMP-2 and MMP-9. In contrast, mRNA expression of tissue inhibitor of metalloproteinase (TIMP)-2 was upregulated by the PTEN gene transfer. Introduction of PTEN gene in glioma cell lines markedly reduced the levels of Rac-GTP and Cdc42-GTP, activated forms of these small GTP-binding proteins, and decreased the phosphorylation levels of focal adhesion kinase. These results suggest that PTEN inhibits glioma cell invasion in two ways: suppressing proteolysis of the extracellular matrix by MMPs and modulating the migratory activity of glioma cells to a less motile nature by inactivating two Rho-family GTP-binding proteins, Rac and Cdc42.
authors.affiliation: Department of Neurosurgery, Ehime University School of Medicine, Shitsukawa, Toon-shi, Ehime 791-0295, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Furukawa
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kumon
authors.forename: Hironobu
authors.initials: H
authors.lastname: Harada
authors.forename: Shohei
authors.initials: S
authors.lastname: Kohno
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Nagato
authors.forename: Mikio
authors.initials: M
authors.lastname: Teraoka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujiwara
authors.forename: Kou
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Hamada
authors.forename: Takanori
authors.initials: T
authors.lastname: Ohnishi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001932:Brain Neoplasms; D045744:Cell Line, Tumor; D002465:Cell Movement; D018920:Coculture Techniques; D015536:Down-Regulation; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D005910:Glioma; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D009361:Neoplasm Invasiveness / Q000473:pathology*; D051059:PTEN Phosphohydrolase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018874:Spheroids, Cellular / Q000473:pathology; D013687:Telencephalon / Q000378:metabolism / Q000473:pathology*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020744:rac GTP-Binding Proteins / Q000378:metabolism
chemical_list: D019716:Tissue Inhibitor of Metalloproteinase-2; D051417:Focal Adhesion Kinase 1; C496050:PTK2 protein, human; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins