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The syndecan-1 ectodomain regulates alphavbeta3 integrin activity in human mammary carcinoma cells.

Beauvais DM, Burbach BJ, Rapraeger AC - J. Cell Biol. (2004)

Bottom Line: This paper demonstrates that the alpha(v)beta(3) integrin and syndecan-1 (S1) are functionally coupled.Coupling of the syndecan to alpha(v)beta(3) requires the S1 ectodomain (ED), as ectopic expression of glycosylphosphatidylinositol-linked S1ED enhances alpha(v)beta(3) recognition of vitronectin; and treatments that target this domain, including competition with recombinant S1ED protein or anti-S1ED antibodies, mutation of the S1ED, or down-regulation of S1 expression by small-interfering RNAs, disrupt alpha(v)beta(3)-dependent cell spreading and migration.Thus, S1 is likely to be a critical regulator of many cellular behaviors that depend on activated alpha(v)beta(3) integrins.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA.

ABSTRACT
The alpha(v)beta(3) integrin participates in cell morphogenesis, growth factor signaling, and cell survival. Activation of the integrin is central to these processes and is influenced by specific ECM components, which engage both integrins and syndecans. This paper demonstrates that the alpha(v)beta(3) integrin and syndecan-1 (S1) are functionally coupled. The integrin is dependent on the syndecan to become activated and to mediate signals required for MDA-MB-231 and MDA-MB-435 human mammary carcinoma cell spreading on vitronectin or S1-specific antibody. Coupling of the syndecan to alpha(v)beta(3) requires the S1 ectodomain (ED), as ectopic expression of glycosylphosphatidylinositol-linked S1ED enhances alpha(v)beta(3) recognition of vitronectin; and treatments that target this domain, including competition with recombinant S1ED protein or anti-S1ED antibodies, mutation of the S1ED, or down-regulation of S1 expression by small-interfering RNAs, disrupt alpha(v)beta(3)-dependent cell spreading and migration. Thus, S1 is likely to be a critical regulator of many cellular behaviors that depend on activated alpha(v)beta(3) integrins.

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Related in: MedlinePlus

Polyclonal S1ED antibodies disrupt αvβ3 integrin–dependent cell spreading on VN. MDA-MB-231 and -435 cells were plated on wells coated with 10 μg/ml VN (top half) or FN (bottom half) in plating medium alone or medium containing 10, 100, or 250 μg/ml of anti-mS1ED pAb. Cells were incubated at 37°C for 2 h, fixed, and stained with rhodamine-conjugated phalloidin. Bar, 50 μm.
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fig4: Polyclonal S1ED antibodies disrupt αvβ3 integrin–dependent cell spreading on VN. MDA-MB-231 and -435 cells were plated on wells coated with 10 μg/ml VN (top half) or FN (bottom half) in plating medium alone or medium containing 10, 100, or 250 μg/ml of anti-mS1ED pAb. Cells were incubated at 37°C for 2 h, fixed, and stained with rhodamine-conjugated phalloidin. Bar, 50 μm.

Mentions: To target the syndecan directly, MDA-MB-231 and MB-435 (αvβ3-positive) cells were treated with S1ED-specific pAb before plating. The pAb recognizes S1 on blots and live cells, but fails to recognize other syndecan family members (unpublished data). The cells display a dose-dependent inhibition in VN-dependent cell spreading over a pAb concentration range of 10–250 μg/ml (Fig. 4). The number of spread cells (diameter ≥20 μm) on VN was reduced from 92 ± 6% in the absence of pAb to 30 ± 4% at 100 μg/ml pAb with almost complete inhibition (≤7%) for both cell types at 250 μg/ml. Note that the treatment of either cell type with pAb does not alter their spreading in response to FN. The relatively high pAb concentration required to achieve full inhibition of spreading may indicate that the “blocking” antibody is a relatively minor fraction of the pAb mix. Treatment of cells with 250 μg/ml of anti-GST pAb has no effect on cell spreading on either matrix ligand (unpublished data).


The syndecan-1 ectodomain regulates alphavbeta3 integrin activity in human mammary carcinoma cells.

Beauvais DM, Burbach BJ, Rapraeger AC - J. Cell Biol. (2004)

Polyclonal S1ED antibodies disrupt αvβ3 integrin–dependent cell spreading on VN. MDA-MB-231 and -435 cells were plated on wells coated with 10 μg/ml VN (top half) or FN (bottom half) in plating medium alone or medium containing 10, 100, or 250 μg/ml of anti-mS1ED pAb. Cells were incubated at 37°C for 2 h, fixed, and stained with rhodamine-conjugated phalloidin. Bar, 50 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2172512&req=5

fig4: Polyclonal S1ED antibodies disrupt αvβ3 integrin–dependent cell spreading on VN. MDA-MB-231 and -435 cells were plated on wells coated with 10 μg/ml VN (top half) or FN (bottom half) in plating medium alone or medium containing 10, 100, or 250 μg/ml of anti-mS1ED pAb. Cells were incubated at 37°C for 2 h, fixed, and stained with rhodamine-conjugated phalloidin. Bar, 50 μm.
Mentions: To target the syndecan directly, MDA-MB-231 and MB-435 (αvβ3-positive) cells were treated with S1ED-specific pAb before plating. The pAb recognizes S1 on blots and live cells, but fails to recognize other syndecan family members (unpublished data). The cells display a dose-dependent inhibition in VN-dependent cell spreading over a pAb concentration range of 10–250 μg/ml (Fig. 4). The number of spread cells (diameter ≥20 μm) on VN was reduced from 92 ± 6% in the absence of pAb to 30 ± 4% at 100 μg/ml pAb with almost complete inhibition (≤7%) for both cell types at 250 μg/ml. Note that the treatment of either cell type with pAb does not alter their spreading in response to FN. The relatively high pAb concentration required to achieve full inhibition of spreading may indicate that the “blocking” antibody is a relatively minor fraction of the pAb mix. Treatment of cells with 250 μg/ml of anti-GST pAb has no effect on cell spreading on either matrix ligand (unpublished data).

Bottom Line: This paper demonstrates that the alpha(v)beta(3) integrin and syndecan-1 (S1) are functionally coupled.Coupling of the syndecan to alpha(v)beta(3) requires the S1 ectodomain (ED), as ectopic expression of glycosylphosphatidylinositol-linked S1ED enhances alpha(v)beta(3) recognition of vitronectin; and treatments that target this domain, including competition with recombinant S1ED protein or anti-S1ED antibodies, mutation of the S1ED, or down-regulation of S1 expression by small-interfering RNAs, disrupt alpha(v)beta(3)-dependent cell spreading and migration.Thus, S1 is likely to be a critical regulator of many cellular behaviors that depend on activated alpha(v)beta(3) integrins.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA.

ABSTRACT
The alpha(v)beta(3) integrin participates in cell morphogenesis, growth factor signaling, and cell survival. Activation of the integrin is central to these processes and is influenced by specific ECM components, which engage both integrins and syndecans. This paper demonstrates that the alpha(v)beta(3) integrin and syndecan-1 (S1) are functionally coupled. The integrin is dependent on the syndecan to become activated and to mediate signals required for MDA-MB-231 and MDA-MB-435 human mammary carcinoma cell spreading on vitronectin or S1-specific antibody. Coupling of the syndecan to alpha(v)beta(3) requires the S1 ectodomain (ED), as ectopic expression of glycosylphosphatidylinositol-linked S1ED enhances alpha(v)beta(3) recognition of vitronectin; and treatments that target this domain, including competition with recombinant S1ED protein or anti-S1ED antibodies, mutation of the S1ED, or down-regulation of S1 expression by small-interfering RNAs, disrupt alpha(v)beta(3)-dependent cell spreading and migration. Thus, S1 is likely to be a critical regulator of many cellular behaviors that depend on activated alpha(v)beta(3) integrins.

Show MeSH
Related in: MedlinePlus