Effects of transforming growth factor-beta 1 on collagen synthesis, integrin expression, adhesion and invasion of glioma cells.
Transforming growth factor-beta 1 (TGF-beta 1) as a potent modulator of cell-extracellular matrix (ECM) interactions may be related to poorly understood ECM-associated features of glioblastomas, such as diffuse brain invasion, rarity of extracranial metastasis and marked ECM production in vitro. We therefore studied TGF-beta 1 expression in glioblastoma biopsy specimens and cell lines by using reverse transcription-polymerase chain reaction (RT-PCR). The cell lines were also examined by Western blotting and immunocytochemistry. To determine effects of TGF-beta 1, glioma cell lines U-138MG and U-373MG were incubated for 48 hours with TGF-beta 1 (0.1, 1, 10 ng/ml) or with antisense phosphorothioate-oligodeoxynucleotides (APO) designed to specifically inhibit TGF-beta 1 gene expression. Thereafter, collagen synthesis was determined by isotopic labeling with 3H-proline; integrin expression by flow cytometry; adhesion on collagen types I and IV, laminin and fibronectin by adhesion assays; and invasion through reconstituted basement membrane by invasion assays. We found that TGF-beta 1 was expressed by all glioma cell lines at protein and mRNA levels. Pretreatment with TGF-beta 1 increased the amount of collagen synthesis/cell, upregulated the alpha 5 integrin chain of U-138MG cells, and facilitated adhesion on all ECM substrates, while invasion of U-138MG cells, but not that of U-373MG cells, was markedly reduced. Conversely, pretreatment with APO reduced TGF-beta 1 protein expression levels, inhibited adhesion and increased invasion of U-138MG cells, but did not affect collagen synthesis. We conclude that exogenously applied TGF-beta 1 exerts marked effects on ECM-related features of glioma cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Paulus
W
W
Institute of Pathology, University of Würzburg, Germany.
Baur
I
I
Huettner
C
C
Schmausser
B
B
Roggendorf
W
W
Schlingensiepen
K H
KH
Brysch
W
W
D001483:Base Sequence; D015153:Blotting, Western; D002448:Cell Adhesion; D002452:Cell Count; D003094:Collagen / Q000096:biosynthesis*; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000737:chemistry* / Q000473:pathology*; D006801:Humans; D016023:Integrins / Q000032:analysis*; D008969:Molecular Sequence Data; D009361:Neoplasm Invasiveness; D016376:Oligonucleotides, Antisense; D016133:Polymerase Chain Reaction / Q000379:methods; D016212:Transforming Growth Factor beta / Q000502:physiology*; D014407:Tumor Cells, Cultured
D016023:Integrins; D016376:Oligonucleotides, Antisense; D016212:Transforming Growth Factor beta; D003094:Collagen