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Heparanase regulates levels of syndecan-1 in the nucleus.

Chen L, Sanderson RD - PLoS ONE (2009)

Bottom Line: This effect requires enzymatically active heparanase because cells expressing high levels of mutated, enzymatically inactive heparanase, failed to diminish syndecan-1 levels in the nucleus.Although heparan sulfate function within the nucleus is not well understood, there is emerging evidence that it may act to repress transcriptional activity.The resulting changes in gene expression facilitated by the loss of nuclear syndecan-1 could explain how heparanase enhances expression of MMP-9, VEGF, tissue factor and perhaps other effectors that condition the tumor microenvironment to promote an aggressive cancer phenotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, USA.

ABSTRACT
Syndecan-1 is a transmembrane heparan sulfate-bearing proteoglycan known to regulate multiple biological functions at the cell surface and within the extracellular matrix. Its functional activity can be modulated by heparanase, an enzyme that cleaves heparan sulfate chains and whose expression has been associated with an aggressive phenotype in many cancers. In addition to remodeling syndecan-1 by cleaving its heparan sulfate chains, heparanase influences syndecan-1 location by upregulating expression of enzymes that accelerate its shedding from the cell surface. In the present study we discovered that heparanase also alters the level of nuclear syndecan-1. Upon upregulation of heparanase expression or following addition of recombinant heparanase to myeloma cells, the nuclear localization of syndecan-1 drops dramatically as revealed by confocal microscopy, western blotting and quantification by ELISA. This effect requires enzymatically active heparanase because cells expressing high levels of mutated, enzymatically inactive heparanase, failed to diminish syndecan-1 levels in the nucleus. Although heparan sulfate function within the nucleus is not well understood, there is emerging evidence that it may act to repress transcriptional activity. The resulting changes in gene expression facilitated by the loss of nuclear syndecan-1 could explain how heparanase enhances expression of MMP-9, VEGF, tissue factor and perhaps other effectors that condition the tumor microenvironment to promote an aggressive cancer phenotype.

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Exogenous recombinant heparanase (rHPSE) decreases nuclear syndecan-1 levels in a concentration-dependent manner.Recombinant heparanase was added to CAG cells having very low levels of heparanase expression (shRNA knockdown cells). Nuclear and non-nuclear fractions were prepared and syndecan-1 levels analyzed by A) western blotting and B) ELISA. Grey bars = non-nuclear fraction; Black bars = nuclear fraction. Error bars represent standard error of the mean. *, P<0.01 vs. nuclear syndecan-1 in cells treated with 0 ng/ml rHPSE.
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pone-0004947-g004: Exogenous recombinant heparanase (rHPSE) decreases nuclear syndecan-1 levels in a concentration-dependent manner.Recombinant heparanase was added to CAG cells having very low levels of heparanase expression (shRNA knockdown cells). Nuclear and non-nuclear fractions were prepared and syndecan-1 levels analyzed by A) western blotting and B) ELISA. Grey bars = non-nuclear fraction; Black bars = nuclear fraction. Error bars represent standard error of the mean. *, P<0.01 vs. nuclear syndecan-1 in cells treated with 0 ng/ml rHPSE.

Mentions: Lastly, as a final confirmation of the effect of heparanase on nuclear syndecan-1 levels, exogenous heparanase was added to cells expressing very low levels of heparanase (heparanase knockdown cells). These experiments were feasible due to the ability of cells, including the CAG cells, to take up and utilize exogenously added heparanase [3], [24], [25]. In response to recombinant heparanase, the level of syndecan-1 present in the nucleus decreased in a concentration dependent fashion (Fig. 4). This confirms results obtained with heparanase transfected cells and strengthens the conclusion that heparanase regulates levels of syndecan-1 in the nucleus. Moreover, the finding that addition of exogenous heparanase can affect nuclear syndecan-1 levels indicates that the level of syndecan-1 in the nucleus of one cell can be altered by uptake of heparanase that was produced by another cell. Thus, heparanase may influence the nuclear localization of syndecan-1 broadly throughout the tumor microenvironment, even within cells lacking heparanase expression.


Heparanase regulates levels of syndecan-1 in the nucleus.

Chen L, Sanderson RD - PLoS ONE (2009)

Exogenous recombinant heparanase (rHPSE) decreases nuclear syndecan-1 levels in a concentration-dependent manner.Recombinant heparanase was added to CAG cells having very low levels of heparanase expression (shRNA knockdown cells). Nuclear and non-nuclear fractions were prepared and syndecan-1 levels analyzed by A) western blotting and B) ELISA. Grey bars = non-nuclear fraction; Black bars = nuclear fraction. Error bars represent standard error of the mean. *, P<0.01 vs. nuclear syndecan-1 in cells treated with 0 ng/ml rHPSE.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2654539&req=5

pone-0004947-g004: Exogenous recombinant heparanase (rHPSE) decreases nuclear syndecan-1 levels in a concentration-dependent manner.Recombinant heparanase was added to CAG cells having very low levels of heparanase expression (shRNA knockdown cells). Nuclear and non-nuclear fractions were prepared and syndecan-1 levels analyzed by A) western blotting and B) ELISA. Grey bars = non-nuclear fraction; Black bars = nuclear fraction. Error bars represent standard error of the mean. *, P<0.01 vs. nuclear syndecan-1 in cells treated with 0 ng/ml rHPSE.
Mentions: Lastly, as a final confirmation of the effect of heparanase on nuclear syndecan-1 levels, exogenous heparanase was added to cells expressing very low levels of heparanase (heparanase knockdown cells). These experiments were feasible due to the ability of cells, including the CAG cells, to take up and utilize exogenously added heparanase [3], [24], [25]. In response to recombinant heparanase, the level of syndecan-1 present in the nucleus decreased in a concentration dependent fashion (Fig. 4). This confirms results obtained with heparanase transfected cells and strengthens the conclusion that heparanase regulates levels of syndecan-1 in the nucleus. Moreover, the finding that addition of exogenous heparanase can affect nuclear syndecan-1 levels indicates that the level of syndecan-1 in the nucleus of one cell can be altered by uptake of heparanase that was produced by another cell. Thus, heparanase may influence the nuclear localization of syndecan-1 broadly throughout the tumor microenvironment, even within cells lacking heparanase expression.

Bottom Line: This effect requires enzymatically active heparanase because cells expressing high levels of mutated, enzymatically inactive heparanase, failed to diminish syndecan-1 levels in the nucleus.Although heparan sulfate function within the nucleus is not well understood, there is emerging evidence that it may act to repress transcriptional activity.The resulting changes in gene expression facilitated by the loss of nuclear syndecan-1 could explain how heparanase enhances expression of MMP-9, VEGF, tissue factor and perhaps other effectors that condition the tumor microenvironment to promote an aggressive cancer phenotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama, USA.

ABSTRACT
Syndecan-1 is a transmembrane heparan sulfate-bearing proteoglycan known to regulate multiple biological functions at the cell surface and within the extracellular matrix. Its functional activity can be modulated by heparanase, an enzyme that cleaves heparan sulfate chains and whose expression has been associated with an aggressive phenotype in many cancers. In addition to remodeling syndecan-1 by cleaving its heparan sulfate chains, heparanase influences syndecan-1 location by upregulating expression of enzymes that accelerate its shedding from the cell surface. In the present study we discovered that heparanase also alters the level of nuclear syndecan-1. Upon upregulation of heparanase expression or following addition of recombinant heparanase to myeloma cells, the nuclear localization of syndecan-1 drops dramatically as revealed by confocal microscopy, western blotting and quantification by ELISA. This effect requires enzymatically active heparanase because cells expressing high levels of mutated, enzymatically inactive heparanase, failed to diminish syndecan-1 levels in the nucleus. Although heparan sulfate function within the nucleus is not well understood, there is emerging evidence that it may act to repress transcriptional activity. The resulting changes in gene expression facilitated by the loss of nuclear syndecan-1 could explain how heparanase enhances expression of MMP-9, VEGF, tissue factor and perhaps other effectors that condition the tumor microenvironment to promote an aggressive cancer phenotype.

Show MeSH
Related in: MedlinePlus