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Contact inhibition of VEGF-induced proliferation requires vascular endothelial cadherin, beta-catenin, and the phosphatase DEP-1/CD148.

Grazia Lampugnani M, Zanetti A, Corada M, Takahashi T, Balconi G, Breviario F, Orsenigo F, Cattelino A, Kemler R, Daniel TO, Dejana E - J. Cell Biol. (2003)

Bottom Line: Comparing isogenic endothelial cells differing for vascular endothelial cadherin (VE-cadherin) expression only, we found that the presence of this protein attenuates VEGF-induced VEGF receptor (VEGFR) 2 phosphorylation in tyrosine, p44/p42 MAP kinase phosphorylation, and cell proliferation.A dominant-negative mutant of high cell density-enhanced PTP 1 (DEP-1)//CD148 as well as reduction of its expression by RNA interference partially restore VEGFR-2 phosphorylation and MAP kinase activation.In sparse cells or in VE-cadherin- cells, this phenomenon cannot occur and the receptor is fully activated by the growth factor.

View Article: PubMed Central - PubMed

Affiliation: FIRC Institute of Molecular Oncology, 20139 Milan, Italy.

ABSTRACT
Confluent endothelial cells respond poorly to the proliferative signals of VEGF. Comparing isogenic endothelial cells differing for vascular endothelial cadherin (VE-cadherin) expression only, we found that the presence of this protein attenuates VEGF-induced VEGF receptor (VEGFR) 2 phosphorylation in tyrosine, p44/p42 MAP kinase phosphorylation, and cell proliferation. VE-cadherin truncated in beta-catenin but not p120 binding domain is unable to associate with VEGFR-2 and to induce its inactivation. beta-Catenin- endothelial cells are not contact inhibited by VE-cadherin and are still responsive to VEGF, indicating that this protein is required to restrain growth factor signaling. A dominant-negative mutant of high cell density-enhanced PTP 1 (DEP-1)//CD148 as well as reduction of its expression by RNA interference partially restore VEGFR-2 phosphorylation and MAP kinase activation. Overall the data indicate that VE-cadherin-beta-catenin complex participates in contact inhibition of VEGF signaling. Upon stimulation with VEGF, VEGFR-2 associates with the complex and concentrates at cell-cell contacts, where it may be inactivated by junctional phosphatases such as DEP-1. In sparse cells or in VE-cadherin- cells, this phenomenon cannot occur and the receptor is fully activated by the growth factor.

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VE-cadherin expression down-regulates tyrosine phosphorylation of VEGFR-2 and phosphorylation of p44/42 MAP kinase over a range of VEGF concentrations. Confluent VEC- and -positive endothelial cells were challenged for 5 min with different concentrations of VEGF (0.8, 8, and 80 ng/ml). Phosphorylated and total VEGFR-2 (A) and p44/42 MAP kinase (B) were assayed as described in the legend to Figs. 2 and 3. The fold increases of receptor and p44/42 MAP kinase phosphorylation in respect to unstimulated cells are reported on the right side of each panel. The SD was 5–15% of the means (three independent experiments).
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fig5: VE-cadherin expression down-regulates tyrosine phosphorylation of VEGFR-2 and phosphorylation of p44/42 MAP kinase over a range of VEGF concentrations. Confluent VEC- and -positive endothelial cells were challenged for 5 min with different concentrations of VEGF (0.8, 8, and 80 ng/ml). Phosphorylated and total VEGFR-2 (A) and p44/42 MAP kinase (B) were assayed as described in the legend to Figs. 2 and 3. The fold increases of receptor and p44/42 MAP kinase phosphorylation in respect to unstimulated cells are reported on the right side of each panel. The SD was 5–15% of the means (three independent experiments).

Mentions: Changing VEGF concentrations, both VEGFR-2 and p44/42 MAP kinase phosphorylation presented a dose-dependent response (Fig. 5). VEC- cells always presented higher receptor phosphorylation and MAP kinase activation at all concentrations of VEGF used.


Contact inhibition of VEGF-induced proliferation requires vascular endothelial cadherin, beta-catenin, and the phosphatase DEP-1/CD148.

Grazia Lampugnani M, Zanetti A, Corada M, Takahashi T, Balconi G, Breviario F, Orsenigo F, Cattelino A, Kemler R, Daniel TO, Dejana E - J. Cell Biol. (2003)

VE-cadherin expression down-regulates tyrosine phosphorylation of VEGFR-2 and phosphorylation of p44/42 MAP kinase over a range of VEGF concentrations. Confluent VEC- and -positive endothelial cells were challenged for 5 min with different concentrations of VEGF (0.8, 8, and 80 ng/ml). Phosphorylated and total VEGFR-2 (A) and p44/42 MAP kinase (B) were assayed as described in the legend to Figs. 2 and 3. The fold increases of receptor and p44/42 MAP kinase phosphorylation in respect to unstimulated cells are reported on the right side of each panel. The SD was 5–15% of the means (three independent experiments).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199373&req=5

fig5: VE-cadherin expression down-regulates tyrosine phosphorylation of VEGFR-2 and phosphorylation of p44/42 MAP kinase over a range of VEGF concentrations. Confluent VEC- and -positive endothelial cells were challenged for 5 min with different concentrations of VEGF (0.8, 8, and 80 ng/ml). Phosphorylated and total VEGFR-2 (A) and p44/42 MAP kinase (B) were assayed as described in the legend to Figs. 2 and 3. The fold increases of receptor and p44/42 MAP kinase phosphorylation in respect to unstimulated cells are reported on the right side of each panel. The SD was 5–15% of the means (three independent experiments).
Mentions: Changing VEGF concentrations, both VEGFR-2 and p44/42 MAP kinase phosphorylation presented a dose-dependent response (Fig. 5). VEC- cells always presented higher receptor phosphorylation and MAP kinase activation at all concentrations of VEGF used.

Bottom Line: Comparing isogenic endothelial cells differing for vascular endothelial cadherin (VE-cadherin) expression only, we found that the presence of this protein attenuates VEGF-induced VEGF receptor (VEGFR) 2 phosphorylation in tyrosine, p44/p42 MAP kinase phosphorylation, and cell proliferation.A dominant-negative mutant of high cell density-enhanced PTP 1 (DEP-1)//CD148 as well as reduction of its expression by RNA interference partially restore VEGFR-2 phosphorylation and MAP kinase activation.In sparse cells or in VE-cadherin- cells, this phenomenon cannot occur and the receptor is fully activated by the growth factor.

View Article: PubMed Central - PubMed

Affiliation: FIRC Institute of Molecular Oncology, 20139 Milan, Italy.

ABSTRACT
Confluent endothelial cells respond poorly to the proliferative signals of VEGF. Comparing isogenic endothelial cells differing for vascular endothelial cadherin (VE-cadherin) expression only, we found that the presence of this protein attenuates VEGF-induced VEGF receptor (VEGFR) 2 phosphorylation in tyrosine, p44/p42 MAP kinase phosphorylation, and cell proliferation. VE-cadherin truncated in beta-catenin but not p120 binding domain is unable to associate with VEGFR-2 and to induce its inactivation. beta-Catenin- endothelial cells are not contact inhibited by VE-cadherin and are still responsive to VEGF, indicating that this protein is required to restrain growth factor signaling. A dominant-negative mutant of high cell density-enhanced PTP 1 (DEP-1)//CD148 as well as reduction of its expression by RNA interference partially restore VEGFR-2 phosphorylation and MAP kinase activation. Overall the data indicate that VE-cadherin-beta-catenin complex participates in contact inhibition of VEGF signaling. Upon stimulation with VEGF, VEGFR-2 associates with the complex and concentrates at cell-cell contacts, where it may be inactivated by junctional phosphatases such as DEP-1. In sparse cells or in VE-cadherin- cells, this phenomenon cannot occur and the receptor is fully activated by the growth factor.

Show MeSH