TY - JOUR
T1 - Phosphatidylinositol 3-kinase function is required for transforming growth factor β-mediated epithelial to mesenchymal transition and cell migration
AU - Bakin, Andrei V.
AU - Tomlinson, Anne K.
AU - Bhowmick, Neil A.
AU - Moses, Harold L.
AU - Arteaga, Carlos L.
PY - 2000/11/24
Y1 - 2000/11/24
N2 - We have studied the role of phosphatidylinositol 3-OH kinase (PI3K)-Akt signaling in transforming growth factor β (TGFβ)-mediated epithelial to mesenchymal transition (EMT). In NMuMG mammary epithelial cells, exogenous TGFβ1 induced phosphorylation of Akt at Ser-473 and Akt in vitro kinase activity against GSK-3β within 30 rain. These responses were temporally correlated with delocalization of E-cadherin, ZO-1, and integrin β1 from cell junctions and the acquisition of spindle cell morphology. LY294002, an inhibitor of the p110 catalytic subunit of PI3K, and a dominant-negative mutant of Akt blocked the delocalization of ZO-1 induced by TGFβ1, whereas transfection of constitutively active p110 induced loss of ZO-1 from tight junctions. In addition, LY294002 blocked TGFβ-mediated C-terminal phosphorylation of Smad2. Consistent with these data, TGFβ-induced p3TP-Lux and p(CAGA)12-Lux reporter activities were inhibited by LY294002 and transiently expressed dominant-negative p85 and Akt mutants in NMuMG and 4T1 cells. Dominant-negative RhoA inhibited TGFβ-induced phosphorylation of Akt at Ser-473, whereas constitutively active RhoA increased the basal phosphorylation of Akt, suggesting that RhoA in involved in TGFβ-induced EMT. Finally, LY294002 and neutralizing TGFβ1 antibodies inhibited ligand-independent constitutively active Akt as well as basal and TGFβ-stimulated migration in 4T1 and EMT6 breast tumor cells. Taken together, these data suggest that PI3K-Akt signaling is required for TGFβ-induced transcriptional responses, EMT, and cell migration.
AB - We have studied the role of phosphatidylinositol 3-OH kinase (PI3K)-Akt signaling in transforming growth factor β (TGFβ)-mediated epithelial to mesenchymal transition (EMT). In NMuMG mammary epithelial cells, exogenous TGFβ1 induced phosphorylation of Akt at Ser-473 and Akt in vitro kinase activity against GSK-3β within 30 rain. These responses were temporally correlated with delocalization of E-cadherin, ZO-1, and integrin β1 from cell junctions and the acquisition of spindle cell morphology. LY294002, an inhibitor of the p110 catalytic subunit of PI3K, and a dominant-negative mutant of Akt blocked the delocalization of ZO-1 induced by TGFβ1, whereas transfection of constitutively active p110 induced loss of ZO-1 from tight junctions. In addition, LY294002 blocked TGFβ-mediated C-terminal phosphorylation of Smad2. Consistent with these data, TGFβ-induced p3TP-Lux and p(CAGA)12-Lux reporter activities were inhibited by LY294002 and transiently expressed dominant-negative p85 and Akt mutants in NMuMG and 4T1 cells. Dominant-negative RhoA inhibited TGFβ-induced phosphorylation of Akt at Ser-473, whereas constitutively active RhoA increased the basal phosphorylation of Akt, suggesting that RhoA in involved in TGFβ-induced EMT. Finally, LY294002 and neutralizing TGFβ1 antibodies inhibited ligand-independent constitutively active Akt as well as basal and TGFβ-stimulated migration in 4T1 and EMT6 breast tumor cells. Taken together, these data suggest that PI3K-Akt signaling is required for TGFβ-induced transcriptional responses, EMT, and cell migration.
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U2 - 10.1074/jbc.M005912200
DO - 10.1074/jbc.M005912200
M3 - Article
C2 - 10969078
AN - SCOPUS:0034711307
SN - 0021-9258
VL - 275
SP - 36803
EP - 36810
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 47
ER -