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Wnt5a is strongly expressed at the leading edge in non-melanoma skin cancer, forming active gradients, while canonical Wnt signalling is repressed.

Pourreyron C, Reilly L, Proby C, Panteleyev A, Fleming C, McLean K, South AP, Foerster J - PLoS ONE (2012)

Bottom Line: Wnt5a is one of the so-called non-canonical Wnt ligands which do not act through β-catenin.In vitro migration assays show that Wnt5a concentration gradients determine its effect on keratinoctye migration: While chemotactic migration is inhibited by Wnt5a present in homogenous concentrations, it is enhanced in the presence of a Wnt5a gradient.This is confirmed by immunohistochemistry showing lack of nuclear β-catenin, as well as absent accumulation of Axin2.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Institute, College of Medicine, Dentistry, and Nursing, University of Dundee, Dundee, Scotland.

ABSTRACT
Wnt5a is one of the so-called non-canonical Wnt ligands which do not act through β-catenin. In normal development, Wnt5a is secreted and directs the migration of target cells along concentration gradients. The effect of Wnt5a on target cells is regulated by many factors, including the expression level of inhibitors and receptors. Dysregulated Wnt5a signalling facilitates invasion of multiple tumor types into adjacent tissue. However, the expression and distribution of Wnt5a in cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), as well as the effect of Wnt5a on keratinocyte migration has not been studied in detail to date. We here report that Wnt5a is upregulated in SCC and BCC and localised to the leading edge of tumors, as well as tumor-associated fibroblasts. The Wnt5a-triggered bundling of its receptor Fzd3 provides evidence of Wnt5a concentration gradients projecting into the tumor. In vitro migration assays show that Wnt5a concentration gradients determine its effect on keratinoctye migration: While chemotactic migration is inhibited by Wnt5a present in homogenous concentrations, it is enhanced in the presence of a Wnt5a gradient. Expression profiling of the Wnt pathway shows that the upregulation of Wnt5a in SCC is coupled to repression of canonical Wnt signalling. This is confirmed by immunohistochemistry showing lack of nuclear β-catenin, as well as absent accumulation of Axin2. Since both types of Wnt signalling act mutually antogonistically at multiple levels, the concurrent repression of canonical Wnt signalling suggests hyper-active Wnt5a signal transduction. Significantly, this combination of gene dysregulation is not observed in the benign hyperproliferative inflammatory skin disease psoriasis. Collectively, our data strongly suggest that Wnt5a signalling contributes to tissue invasion by non-melanoma skin cancer.

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Related in: MedlinePlus

Spatial relationship of Wnt5a, Fzd3, and Fzd5 localization in basal cell carcinoma.Immunohistochemistry of serially cut samples stained for Wnt5a, Fzd5, or Fzd3 as indicated, magnification: 100× (top row), 200× (middle, bottom rows).
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pone-0031827-g005: Spatial relationship of Wnt5a, Fzd3, and Fzd5 localization in basal cell carcinoma.Immunohistochemistry of serially cut samples stained for Wnt5a, Fzd5, or Fzd3 as indicated, magnification: 100× (top row), 200× (middle, bottom rows).

Mentions: We next studied the spatial relationship of Wnt5a, Fzd3, and Fzd5 in individual tumor samples. To this end, we determined staining intensities of these proteins in serial sections of individual tumors, respectively, since antibodies suitable for co-immunofluorescence in paraffin-embedded samples were unavailable. As shown in figure 4, Wnt5a was predominantly expressed on tumor margins in SCC (as well as in tumor associated stroma). By contrast, Fzd3 localized to cells within the tumor mass, sometimes forming nest-like Fzd3-positive tumor-domains (middle panel, white arrow head) and, as described above, exhibiting focally polarised intracellular distribution. Fzd5 exhibited heterogenous intra-tumor distribution, being localised to intra-tumor clusters (top), weak/diffusely at the edge (bottom), or homogenously throughout (middle). Analogous arrangements were observed in BCC, with Wnt5a being most strongly expressed at the leading edge, as well as in tumor-associated stroma (figure 5, left panels), while Fzd3 showed polarised expression within the tumor (figure 5, top middle), or in Fzd3-positive nests (white arrow heads). Fzd5 was weak or absent in most BCCs (bottom right, cf. table 1). Where expressed, Fzd5 exhibited diffuse intra-tumor localisation (upper right), or at the tumor edge (middle right). Taken together, the data show that Wnt5a and its receptors are expressed by non-overlapping sub-populations. The strong expression of Wnt5a at the leading edge, as well as in tumor-surrounding stroma cells, in conjunction with the polarised expression of Fzd3 within the tumor mass suggest that Wnt5a gradients project into the tumor to enhance motility in distinct subpopulations.


Wnt5a is strongly expressed at the leading edge in non-melanoma skin cancer, forming active gradients, while canonical Wnt signalling is repressed.

Pourreyron C, Reilly L, Proby C, Panteleyev A, Fleming C, McLean K, South AP, Foerster J - PLoS ONE (2012)

Spatial relationship of Wnt5a, Fzd3, and Fzd5 localization in basal cell carcinoma.Immunohistochemistry of serially cut samples stained for Wnt5a, Fzd5, or Fzd3 as indicated, magnification: 100× (top row), 200× (middle, bottom rows).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3285195&req=5

pone-0031827-g005: Spatial relationship of Wnt5a, Fzd3, and Fzd5 localization in basal cell carcinoma.Immunohistochemistry of serially cut samples stained for Wnt5a, Fzd5, or Fzd3 as indicated, magnification: 100× (top row), 200× (middle, bottom rows).
Mentions: We next studied the spatial relationship of Wnt5a, Fzd3, and Fzd5 in individual tumor samples. To this end, we determined staining intensities of these proteins in serial sections of individual tumors, respectively, since antibodies suitable for co-immunofluorescence in paraffin-embedded samples were unavailable. As shown in figure 4, Wnt5a was predominantly expressed on tumor margins in SCC (as well as in tumor associated stroma). By contrast, Fzd3 localized to cells within the tumor mass, sometimes forming nest-like Fzd3-positive tumor-domains (middle panel, white arrow head) and, as described above, exhibiting focally polarised intracellular distribution. Fzd5 exhibited heterogenous intra-tumor distribution, being localised to intra-tumor clusters (top), weak/diffusely at the edge (bottom), or homogenously throughout (middle). Analogous arrangements were observed in BCC, with Wnt5a being most strongly expressed at the leading edge, as well as in tumor-associated stroma (figure 5, left panels), while Fzd3 showed polarised expression within the tumor (figure 5, top middle), or in Fzd3-positive nests (white arrow heads). Fzd5 was weak or absent in most BCCs (bottom right, cf. table 1). Where expressed, Fzd5 exhibited diffuse intra-tumor localisation (upper right), or at the tumor edge (middle right). Taken together, the data show that Wnt5a and its receptors are expressed by non-overlapping sub-populations. The strong expression of Wnt5a at the leading edge, as well as in tumor-surrounding stroma cells, in conjunction with the polarised expression of Fzd3 within the tumor mass suggest that Wnt5a gradients project into the tumor to enhance motility in distinct subpopulations.

Bottom Line: Wnt5a is one of the so-called non-canonical Wnt ligands which do not act through β-catenin.In vitro migration assays show that Wnt5a concentration gradients determine its effect on keratinoctye migration: While chemotactic migration is inhibited by Wnt5a present in homogenous concentrations, it is enhanced in the presence of a Wnt5a gradient.This is confirmed by immunohistochemistry showing lack of nuclear β-catenin, as well as absent accumulation of Axin2.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Institute, College of Medicine, Dentistry, and Nursing, University of Dundee, Dundee, Scotland.

ABSTRACT
Wnt5a is one of the so-called non-canonical Wnt ligands which do not act through β-catenin. In normal development, Wnt5a is secreted and directs the migration of target cells along concentration gradients. The effect of Wnt5a on target cells is regulated by many factors, including the expression level of inhibitors and receptors. Dysregulated Wnt5a signalling facilitates invasion of multiple tumor types into adjacent tissue. However, the expression and distribution of Wnt5a in cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), as well as the effect of Wnt5a on keratinocyte migration has not been studied in detail to date. We here report that Wnt5a is upregulated in SCC and BCC and localised to the leading edge of tumors, as well as tumor-associated fibroblasts. The Wnt5a-triggered bundling of its receptor Fzd3 provides evidence of Wnt5a concentration gradients projecting into the tumor. In vitro migration assays show that Wnt5a concentration gradients determine its effect on keratinoctye migration: While chemotactic migration is inhibited by Wnt5a present in homogenous concentrations, it is enhanced in the presence of a Wnt5a gradient. Expression profiling of the Wnt pathway shows that the upregulation of Wnt5a in SCC is coupled to repression of canonical Wnt signalling. This is confirmed by immunohistochemistry showing lack of nuclear β-catenin, as well as absent accumulation of Axin2. Since both types of Wnt signalling act mutually antogonistically at multiple levels, the concurrent repression of canonical Wnt signalling suggests hyper-active Wnt5a signal transduction. Significantly, this combination of gene dysregulation is not observed in the benign hyperproliferative inflammatory skin disease psoriasis. Collectively, our data strongly suggest that Wnt5a signalling contributes to tissue invasion by non-melanoma skin cancer.

Show MeSH
Related in: MedlinePlus