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Overexpressed β-catenin localizes to plasma membrane in respiratory papillomas.

Lucs AV, Abramson AL, Steinberg BM - J. Invest. Dermatol. (2014)

View Article: PubMed Central - PubMed

Affiliation: Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, New York, USA.

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Recurrent respiratory papillomatosis (RRP), a disease characterized by recurrent tumors of the upper airway, is caused by human papillomavirus (HPV) types 6 and 11... The localization of β-catenin at the plasma membrane was observed in all papillomas analyzed, regardless of the age of onset or the severity of the papillomatosis... Moreover, PKG levels were generally lower in papillomas (Figure 1E)... Thus, HPV 6/11 infection effectively suppresses both mediators of β-catenin degradation, inactivating one kinase and reducing levels of the other... Total actin levels do not differ significantly between papilloma cells and normal cells (data not shown). α-catenin, which mediates β-catenin’s recruitment of actin to the plasma membrane, was also more cytoplasmically diffuse in papillomas (Figure 2B)... We therefore suggest the increased β-catenin in respiratory papillomas results in, or is associated with, it’s decoupling from the actin cytoskeleton... Interestingly, there is a growing body of literature which suggests that the actin cytoskeleton is an active regulator of differentiation of cells in a stratified epithelium. siRNA depletion of ROCK2, a serine/threonine kinase that regulates the cytoskeleton and cell adhesion, suppresses terminal differentiation of keratinocytes Conversely, activation of ROCK2 promotes differentiation... More direct evidence comes from a study showing that disruption of actin filaments using latrunculin A results in aberrant expression of differentiation markers... We have previously reported that differentiation is altered in respiratory papillomas, and others have reported that HPV pathogenicity is dependent on altering the differentiation pattern... It is clear that the low-risk HPVs are not causing nuclear translocation of β-catenin in respiratory papillomas... Rather, we postulate that they regulate the actin cytoskeleton through manipulation of β-catenin at the cell membrane as a mechanism for altering differentiation.

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β-catenin localizes to the plasma membrane in respiratory papillomasPapilloma and clinically normal tissue from the same patient were stained for β-catenin (red) and E-cadherin (green). DAPI (blue) was used to stain the nucleus. The scale bar represents 20 μm. (A) Representative western blots of biopsies of clinically normal tissue (CN) and papilloma tissue (P) from RRP patients. (B) Relative β-catenin mRNA levels, normalized to GAPDH. (C) and (D) western blots of phospho-GSK3β and PKG respectively. N indicates normal samples from a non-RRP patient. Donors of the tissues were numbered sequentially. CN6a and CN6b were clinically normal tissue from two sites in the airway of patient 6. Actin was used as a loading control.
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Figure 1: β-catenin localizes to the plasma membrane in respiratory papillomasPapilloma and clinically normal tissue from the same patient were stained for β-catenin (red) and E-cadherin (green). DAPI (blue) was used to stain the nucleus. The scale bar represents 20 μm. (A) Representative western blots of biopsies of clinically normal tissue (CN) and papilloma tissue (P) from RRP patients. (B) Relative β-catenin mRNA levels, normalized to GAPDH. (C) and (D) western blots of phospho-GSK3β and PKG respectively. N indicates normal samples from a non-RRP patient. Donors of the tissues were numbered sequentially. CN6a and CN6b were clinically normal tissue from two sites in the airway of patient 6. Actin was used as a loading control.

Mentions: β-catenin localization was determined by immunofluorescence, using E-cadherin as a marker of the plasma membrane and DAPI to mark the nuclei (Figure 1A). There was very strong co-localization of β-catenin with E-cadherin at the plasma membrane, but no evidence of nuclear localization, suggesting that β-catenin was not induced to translocate to the nucleus by HPV 6/11. The localization of β-catenin at the plasma membrane was observed in all papillomas analyzed, regardless of the age of onset or the severity of the papillomatosis. To confirm that β-catenin target genes are not upregulated in papillomas, we reassessed data from our previously published microarray studies that compared mRNA isolated from matched pairs of papillomas and normal laryngeal tissues from 12 RRP patients (DeVoti et al., 2008). The microarrays included probes for 15 of the confirmed human β-catenin transcriptional targets; myc, cyclin D1, c-jun, uPAR, CD44, ephrin B1, claudin1, vascular endothelial growth factor (VEGF), Met, Endothelin-1, Jagged 1, FGF9, FGF20, Sox9 and Sox17 (Nusse, 2009). Of these, only VEGF was modestly upregulated (data not shown). However, VEGF can be induced by activation of the EFGR, via transcription factors SP1 and AP2 (Pore et al., 2006). Since the EGFR is overexpressed and highly active in papillomas (Johnston et al., 1999), it is likely that VEGF was being induced by this mechanism and not by β-catenin activity.


Overexpressed β-catenin localizes to plasma membrane in respiratory papillomas.

Lucs AV, Abramson AL, Steinberg BM - J. Invest. Dermatol. (2014)

β-catenin localizes to the plasma membrane in respiratory papillomasPapilloma and clinically normal tissue from the same patient were stained for β-catenin (red) and E-cadherin (green). DAPI (blue) was used to stain the nucleus. The scale bar represents 20 μm. (A) Representative western blots of biopsies of clinically normal tissue (CN) and papilloma tissue (P) from RRP patients. (B) Relative β-catenin mRNA levels, normalized to GAPDH. (C) and (D) western blots of phospho-GSK3β and PKG respectively. N indicates normal samples from a non-RRP patient. Donors of the tissues were numbered sequentially. CN6a and CN6b were clinically normal tissue from two sites in the airway of patient 6. Actin was used as a loading control.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4020987&req=5

Figure 1: β-catenin localizes to the plasma membrane in respiratory papillomasPapilloma and clinically normal tissue from the same patient were stained for β-catenin (red) and E-cadherin (green). DAPI (blue) was used to stain the nucleus. The scale bar represents 20 μm. (A) Representative western blots of biopsies of clinically normal tissue (CN) and papilloma tissue (P) from RRP patients. (B) Relative β-catenin mRNA levels, normalized to GAPDH. (C) and (D) western blots of phospho-GSK3β and PKG respectively. N indicates normal samples from a non-RRP patient. Donors of the tissues were numbered sequentially. CN6a and CN6b were clinically normal tissue from two sites in the airway of patient 6. Actin was used as a loading control.
Mentions: β-catenin localization was determined by immunofluorescence, using E-cadherin as a marker of the plasma membrane and DAPI to mark the nuclei (Figure 1A). There was very strong co-localization of β-catenin with E-cadherin at the plasma membrane, but no evidence of nuclear localization, suggesting that β-catenin was not induced to translocate to the nucleus by HPV 6/11. The localization of β-catenin at the plasma membrane was observed in all papillomas analyzed, regardless of the age of onset or the severity of the papillomatosis. To confirm that β-catenin target genes are not upregulated in papillomas, we reassessed data from our previously published microarray studies that compared mRNA isolated from matched pairs of papillomas and normal laryngeal tissues from 12 RRP patients (DeVoti et al., 2008). The microarrays included probes for 15 of the confirmed human β-catenin transcriptional targets; myc, cyclin D1, c-jun, uPAR, CD44, ephrin B1, claudin1, vascular endothelial growth factor (VEGF), Met, Endothelin-1, Jagged 1, FGF9, FGF20, Sox9 and Sox17 (Nusse, 2009). Of these, only VEGF was modestly upregulated (data not shown). However, VEGF can be induced by activation of the EFGR, via transcription factors SP1 and AP2 (Pore et al., 2006). Since the EGFR is overexpressed and highly active in papillomas (Johnston et al., 1999), it is likely that VEGF was being induced by this mechanism and not by β-catenin activity.

View Article: PubMed Central - PubMed

Affiliation: Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, New York, USA.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Recurrent respiratory papillomatosis (RRP), a disease characterized by recurrent tumors of the upper airway, is caused by human papillomavirus (HPV) types 6 and 11... The localization of β-catenin at the plasma membrane was observed in all papillomas analyzed, regardless of the age of onset or the severity of the papillomatosis... Moreover, PKG levels were generally lower in papillomas (Figure 1E)... Thus, HPV 6/11 infection effectively suppresses both mediators of β-catenin degradation, inactivating one kinase and reducing levels of the other... Total actin levels do not differ significantly between papilloma cells and normal cells (data not shown). α-catenin, which mediates β-catenin’s recruitment of actin to the plasma membrane, was also more cytoplasmically diffuse in papillomas (Figure 2B)... We therefore suggest the increased β-catenin in respiratory papillomas results in, or is associated with, it’s decoupling from the actin cytoskeleton... Interestingly, there is a growing body of literature which suggests that the actin cytoskeleton is an active regulator of differentiation of cells in a stratified epithelium. siRNA depletion of ROCK2, a serine/threonine kinase that regulates the cytoskeleton and cell adhesion, suppresses terminal differentiation of keratinocytes Conversely, activation of ROCK2 promotes differentiation... More direct evidence comes from a study showing that disruption of actin filaments using latrunculin A results in aberrant expression of differentiation markers... We have previously reported that differentiation is altered in respiratory papillomas, and others have reported that HPV pathogenicity is dependent on altering the differentiation pattern... It is clear that the low-risk HPVs are not causing nuclear translocation of β-catenin in respiratory papillomas... Rather, we postulate that they regulate the actin cytoskeleton through manipulation of β-catenin at the cell membrane as a mechanism for altering differentiation.

Show MeSH
Related in: MedlinePlus