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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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Related in: MedlinePlus

Heparanase enzymatic activity is required for reduction of syndecan-1 levels in the nucleus.Nuclear and non-nuclear fractions were prepared from CAG cells expressing high levels of wild-type heparanase (HPSE-high) or heparanase mutated at either amino acid 343 (M343) or amino acid 225 (M225) which renders them enzymatically inactive. All cells were prepared using pIRES2 vectors for transfections. Fractions were analyzed for syndecan-1 levels 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 HPSE high cells.
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pone-0004947-g003: Heparanase enzymatic activity is required for reduction of syndecan-1 levels in the nucleus.Nuclear and non-nuclear fractions were prepared from CAG cells expressing high levels of wild-type heparanase (HPSE-high) or heparanase mutated at either amino acid 343 (M343) or amino acid 225 (M225) which renders them enzymatically inactive. All cells were prepared using pIRES2 vectors for transfections. Fractions were analyzed for syndecan-1 levels 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 HPSE high cells.

Mentions: Because heparanase can have biological functions that are independent of its heparan sulfate degrading activity [1], we also examined nuclear syndecan-1 levels in cells transfected with mutated heparanase that lacks enzyme activity. Cells expressing these mutated forms of heparanase retained substantial nuclear syndecan-1 as compared to cells expressing the active enzyme (Fig. 3). This indicates that the regulation of syndecan-1 level in the nucleus is dependent, at least in part, on the heparan sulfate degrading activity of heparanase. In addition, cells transfected with the cDNA for the mutated enzyme act as an additional negative control for these studies because in each of the two mutation constructs only a single amino acid is altered, yet nuclear syndecan-1 levels are retained [3], [23].


Heparanase regulates levels of syndecan-1 in the nucleus.

Chen L, Sanderson RD - PLoS ONE (2009)

Heparanase enzymatic activity is required for reduction of syndecan-1 levels in the nucleus.Nuclear and non-nuclear fractions were prepared from CAG cells expressing high levels of wild-type heparanase (HPSE-high) or heparanase mutated at either amino acid 343 (M343) or amino acid 225 (M225) which renders them enzymatically inactive. All cells were prepared using pIRES2 vectors for transfections. Fractions were analyzed for syndecan-1 levels 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 HPSE high cells.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0004947-g003: Heparanase enzymatic activity is required for reduction of syndecan-1 levels in the nucleus.Nuclear and non-nuclear fractions were prepared from CAG cells expressing high levels of wild-type heparanase (HPSE-high) or heparanase mutated at either amino acid 343 (M343) or amino acid 225 (M225) which renders them enzymatically inactive. All cells were prepared using pIRES2 vectors for transfections. Fractions were analyzed for syndecan-1 levels 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 HPSE high cells.
Mentions: Because heparanase can have biological functions that are independent of its heparan sulfate degrading activity [1], we also examined nuclear syndecan-1 levels in cells transfected with mutated heparanase that lacks enzyme activity. Cells expressing these mutated forms of heparanase retained substantial nuclear syndecan-1 as compared to cells expressing the active enzyme (Fig. 3). This indicates that the regulation of syndecan-1 level in the nucleus is dependent, at least in part, on the heparan sulfate degrading activity of heparanase. In addition, cells transfected with the cDNA for the mutated enzyme act as an additional negative control for these studies because in each of the two mutation constructs only a single amino acid is altered, yet nuclear syndecan-1 levels are retained [3], [23].

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