Role of Rap1B and tumor suppressor PTEN in the negative regulation of lysophosphatidic acid--induced migration by isoproterenol in glioma cells.
The clarification of mechanisms that negatively regulate the invasive behavior of human glioma cells is of great importance in order to find new methods of treatment. In this study, we have focused on the negative regulation of lysophosphatidic acid (LPA)-induced migration in glioma cells. Using small interference RNA and dominant-negative gene strategies in addition to pharmacological tools, we found that isoproterenol (ISO) and sphingosine-1-phosphate (S1P) negatively but differently regulate the LPA-induced migration. ISO-induced suppression of the migration of glioma cells occurs via beta(2)-adrenergic receptor/cAMP/Epac/Rap1B/inhibition of Rac, whereas S1P has been shown to suppress the migration of the cells through S1P(2) receptor/Rho-mediated down-regulation of Rac1. The expression of tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is required for the inhibitory ISO-induced and Rap1B-mediated actions on the migration, Rac1 activation, and Akt activation in response to LPA. Thus, the PTEN-mediated down-regulation of phosphatidylinositol 3-kinase activity may be involved in the regulation of Rap1B-dependent inhibition of Rac1 activity. These findings suggest that there are at least two distinct inhibitory pathways, which are mediated by the S1P(2) receptor and beta(2)-adrenergic receptor, to control the migratory, hence invasive, behavior of glioma cells.
Malchinkhuu
Enkhzol
E
Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan.
Sato
Koichi
K
Maehama
Tomohiko
T
Ishiuchi
Shogo
S
Yoshimoto
Yuhei
Y
Mogi
Chihiro
C
Kimura
Takao
T
Kurose
Hitoshi
H
Tomura
Hideaki
H
Okajima
Fumikazu
F
D002465:Cell Movement / Q000187:drug effects*; D000242:Cyclic AMP / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005910:Glioma / Q000201:enzymology* / Q000473:pathology*; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology*; D008246:Lysophospholipids / Q000494:pharmacology*; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020668:rap GTP-Binding Proteins / Q000378:metabolism*
D008246:Lysophospholipids; C060506:sphingosine 1-phosphate; D000242:Cyclic AMP; D051057:Proto-Oncogene Proteins c-akt; D017868:Cyclic AMP-Dependent Protein Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; C116753:RAP1B protein, human; D020830:rac1 GTP-Binding Protein; D020668:rap GTP-Binding Proteins; D007545:Isoproterenol; D013110:Sphingosine; C032881:lysophosphatidic acid