Transforming growth factor-beta1-dependent activation of Smad2/3 and up-regulation of PAI-1 expression is negatively regulated by Src in SKOV-3 human ovarian cancer cells.
The net balance between urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1) has been implicated in tumor cell invasion and metastasis. To elucidate the mechanism of the transforming growth factor-beta1 (TGF-beta1)-dependent up-regulation of PAI-1 expression, we investigated which signaling pathway transduced by TGF-beta1 is responsible for this effect. Here, we show (1) nontoxic concentrations of TGF-beta1 up-regulates uPA expression in HRA and SKOV-3 human ovarian cancer cells, (2) TGF-beta1 activates Smads (phosphorylation of Smad2 and nuclear translocation of Smad3) and subsequently up-regulates PAI-1 expression in HRA cells, whereas TGF-beta1 neither activates Smads nor up-regulates PAI-1 in SKOV-3 cells, (3) pharmacological Src inhibitor PP2 or antisense (AS) c-Src oligodeoxynucleotide (ODN) treatment significantly induces TGF-beta1-dependent activation of Smads, leading to PAI-1 synthesis, compared with controls, in SKOV-3 cells, (4) combination of TGF-beta1 and PP2, which activates PAI-1 expression and reduces uPA expression in SKOV-3, results in decreased invasiveness, (5) pharmacological inhibitors for mitogen-activated protein kinase (MAPK) (PD98059) and phosphoinositide-3-kinase (PI3K) (LY294002 and wortmannin) or AS-PI3K ODN transfection do not affect TGF-beta1-induced Smad signaling and up-regulation of PAI-1 expression in SKOV-3 cells pretreated with PP2, and (6) the induction of PAI-1 protein was partially inhibited by an inhibitor of Sp1-DNA binding, mithramycin, implicating, at least in part, Sp1 in the regulation of this gene by TGF-beta1. In conclusion, TGF-beta1-dependent activation of Smad2/3, leading to PAI-1 synthesis, may be negatively regulated by Src, but not its downstream targets MAPK and PI3K in SKOV-3 cells. These data also reflect the complex biological effect of uPA-PAI-1 system.
Wakahara
Kiyoshi
K
NetForce Co. Ltd., Taiko 3-1-18, Nakamura, Nagoya, Aichi 453-0801, Japan.
Kobayashi
Hiroshi
H
Yagyu
Tatsuo
T
Matsuzaki
Hidenori
H
Kondo
Toshiharu
T
Kurita
Noriyuki
N
Sekino
Hideo
H
Inagaki
Kiyokazu
K
Suzuki
Mika
M
Kanayama
Naohiro
N
Terao
Toshihiko
T
D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000502:physiology; D010051:Ovarian Neoplasms / Q000378:metabolism; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology; D051899:Smad2 Protein; D051900:Smad3 Protein; D015534:Trans-Activators / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D053773:Transforming Growth Factor beta1; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000502:physiology; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
C412373:AG 1879; D004268:DNA-Binding Proteins; D005419:Flavonoids; D047908:Intracellular Signaling Peptides and Proteins; D017395:Plasminogen Activator Inhibitor 1; D011743:Pyrimidines; C497782:SMAD2 protein, human; C497790:SMAD3 protein, human; D051899:Smad2 Protein; D051900:Smad3 Protein; C508960:TGFB1 protein, human; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C015482:protein kinase modulator; D011494:Protein Kinases; C065999:Sp1 kinase; D019061:src-Family Kinases; D014568:Urokinase-Type Plasminogen Activator; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one