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Hypoxia Up-Regulates Galectin-3 in Mammary Tumor Progression and Metastasis.

de Oliveira JT, Ribeiro C, Barros R, Gomes C, de Matos AJ, Reis CA, Rutteman GR, Gärtner F - PLoS ONE (2015)

Bottom Line: Increased galectin-3 expression was confirmed at the mRNA level.Under hypoxic conditions the expression of galectin-3 shifts from a predominant nuclear location to cytoplasmic and membrane expressions.In in vivo studies, galectin-3 was overexpressed in hypoxic areas of primary tumors and well-established metastases.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology (IPATIMUP), University of Porto, Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), University of Porto, Porto, Portugal; Faculty of Veterinary Medicine of the Lusophone University of Humanities and Technologies, Lisbon, Portugal.

ABSTRACT
The tumor microenvironment encompasses several stressful conditions for cancer cells such as hypoxia, oxidative stress and pH alterations. Galectin-3, a well-studied member of the beta-galactoside-binding animal family of lectins has been implicated in multiple steps of metastasis as cell-cell and cell-ECM adhesion, promotion of angiogenesis, cell proliferation and resistance to apoptosis. However, both its aberrantly up- and down-regulated expression was observed in several types of cancer. Thus, the mechanisms that regulate galectin-3 expression in neoplastic settings are not clear. In order to demonstrate the putative role of hypoxia in regulating galectin-3 expression in canine mammary tumors (CMT), in vitro and in vivo studies were performed. In malignant CMT cells, hypoxia was observed to induce expression of galectin-3, a phenomenon that was almost completely prevented by catalase treatment of CMT-U27 cells. Increased galectin-3 expression was confirmed at the mRNA level. Under hypoxic conditions the expression of galectin-3 shifts from a predominant nuclear location to cytoplasmic and membrane expressions. In in vivo studies, galectin-3 was overexpressed in hypoxic areas of primary tumors and well-established metastases. Tumor hypoxia thus up-regulates the expression of galectin-3, which may in turn increase tumor aggressiveness.

No MeSH data available.


Related in: MedlinePlus

Subcellular localization of galectin-3 and GLUT-1.Subcellular localization of galectin-3 (green color) and GLUT-1 (red color) under normoxic and hypoxic conditions was assessed by double-labeling immunofluorescence and observed by laser scanning confocal microscopy. Under normoxic conditions galectin-3 had a nuclear and cytoplasmic localization. However, in hypoxic conditions galectin-3 expression was mainly cytoplasmic. Galectin-3 localization differed in hydrogen peroxide and catalase treated cells under normoxic and hypoxic conditions. Following hydrogen peroxide treatment in CMT-U27 cells under normal oxygen conditions, galectin-3 left the cytoplasm and was mainly localized in the nucleus. Nevertheless, in hydrogen peroxide treated cells under hypoxia galectin-3 was mostly cytoplasmic. Catalase treated CMT-U27 cells under normoxia presented galectin-3 in specific organelles; however in catalase-treated hypoxic cells galectin-3 localization was again mostly cytoplasmic.
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pone.0134458.g003: Subcellular localization of galectin-3 and GLUT-1.Subcellular localization of galectin-3 (green color) and GLUT-1 (red color) under normoxic and hypoxic conditions was assessed by double-labeling immunofluorescence and observed by laser scanning confocal microscopy. Under normoxic conditions galectin-3 had a nuclear and cytoplasmic localization. However, in hypoxic conditions galectin-3 expression was mainly cytoplasmic. Galectin-3 localization differed in hydrogen peroxide and catalase treated cells under normoxic and hypoxic conditions. Following hydrogen peroxide treatment in CMT-U27 cells under normal oxygen conditions, galectin-3 left the cytoplasm and was mainly localized in the nucleus. Nevertheless, in hydrogen peroxide treated cells under hypoxia galectin-3 was mostly cytoplasmic. Catalase treated CMT-U27 cells under normoxia presented galectin-3 in specific organelles; however in catalase-treated hypoxic cells galectin-3 localization was again mostly cytoplasmic.

Mentions: Galectin-3 actions rely on its subcellular location and on the phenotype of the cell itself, ranging from a pro-apoptotic function effect when present in the nucleus, to an anti-apoptotic one when in the cytoplasm [37]. As a cell membrane protein, it also regulates cell-cell and/or cell-extracellular matrix adhesion [38]. To assess a putative effect of hypoxia and oxidative stress on the subcellular location of galectin-3, we analyzed galectin-3 and GLUT-1 double-labeled cells under a confocal microscope (Fig 3). Untreated normoxic cells expressed galectin-3 in the cytoplasm and to a lesser extent in the nucleus. However when untreated CMT-U27 cells were exposed to hypoxia galectin-3 nuclear expression could no longer be found. Cells treated with H2O2, under normal oxygen conditions, showed increased nuclear galectin-3 expression. However, when cells were exposed to both H2O2 and hypoxia, nuclear galectin-3 expression was lost, its subcellular localization being again mainly cytoplasmic. Under these conditions, in a few CMT-U27 cells, particularly in focal contact points, galectin-3 was co-located with GLUT-1 at the cell membrane. Finally, catalase-treated CMT-U27 cells under normal oxygen conditions expressed galectin-3 in specific organelles of irregularly-shaped cells, while cells under hypoxic conditions (1% O2) cells retained their morphology and, when present, a cytoplasmic location of galectin-3 was found (Fig 3).


Hypoxia Up-Regulates Galectin-3 in Mammary Tumor Progression and Metastasis.

de Oliveira JT, Ribeiro C, Barros R, Gomes C, de Matos AJ, Reis CA, Rutteman GR, Gärtner F - PLoS ONE (2015)

Subcellular localization of galectin-3 and GLUT-1.Subcellular localization of galectin-3 (green color) and GLUT-1 (red color) under normoxic and hypoxic conditions was assessed by double-labeling immunofluorescence and observed by laser scanning confocal microscopy. Under normoxic conditions galectin-3 had a nuclear and cytoplasmic localization. However, in hypoxic conditions galectin-3 expression was mainly cytoplasmic. Galectin-3 localization differed in hydrogen peroxide and catalase treated cells under normoxic and hypoxic conditions. Following hydrogen peroxide treatment in CMT-U27 cells under normal oxygen conditions, galectin-3 left the cytoplasm and was mainly localized in the nucleus. Nevertheless, in hydrogen peroxide treated cells under hypoxia galectin-3 was mostly cytoplasmic. Catalase treated CMT-U27 cells under normoxia presented galectin-3 in specific organelles; however in catalase-treated hypoxic cells galectin-3 localization was again mostly cytoplasmic.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4519331&req=5

pone.0134458.g003: Subcellular localization of galectin-3 and GLUT-1.Subcellular localization of galectin-3 (green color) and GLUT-1 (red color) under normoxic and hypoxic conditions was assessed by double-labeling immunofluorescence and observed by laser scanning confocal microscopy. Under normoxic conditions galectin-3 had a nuclear and cytoplasmic localization. However, in hypoxic conditions galectin-3 expression was mainly cytoplasmic. Galectin-3 localization differed in hydrogen peroxide and catalase treated cells under normoxic and hypoxic conditions. Following hydrogen peroxide treatment in CMT-U27 cells under normal oxygen conditions, galectin-3 left the cytoplasm and was mainly localized in the nucleus. Nevertheless, in hydrogen peroxide treated cells under hypoxia galectin-3 was mostly cytoplasmic. Catalase treated CMT-U27 cells under normoxia presented galectin-3 in specific organelles; however in catalase-treated hypoxic cells galectin-3 localization was again mostly cytoplasmic.
Mentions: Galectin-3 actions rely on its subcellular location and on the phenotype of the cell itself, ranging from a pro-apoptotic function effect when present in the nucleus, to an anti-apoptotic one when in the cytoplasm [37]. As a cell membrane protein, it also regulates cell-cell and/or cell-extracellular matrix adhesion [38]. To assess a putative effect of hypoxia and oxidative stress on the subcellular location of galectin-3, we analyzed galectin-3 and GLUT-1 double-labeled cells under a confocal microscope (Fig 3). Untreated normoxic cells expressed galectin-3 in the cytoplasm and to a lesser extent in the nucleus. However when untreated CMT-U27 cells were exposed to hypoxia galectin-3 nuclear expression could no longer be found. Cells treated with H2O2, under normal oxygen conditions, showed increased nuclear galectin-3 expression. However, when cells were exposed to both H2O2 and hypoxia, nuclear galectin-3 expression was lost, its subcellular localization being again mainly cytoplasmic. Under these conditions, in a few CMT-U27 cells, particularly in focal contact points, galectin-3 was co-located with GLUT-1 at the cell membrane. Finally, catalase-treated CMT-U27 cells under normal oxygen conditions expressed galectin-3 in specific organelles of irregularly-shaped cells, while cells under hypoxic conditions (1% O2) cells retained their morphology and, when present, a cytoplasmic location of galectin-3 was found (Fig 3).

Bottom Line: Increased galectin-3 expression was confirmed at the mRNA level.Under hypoxic conditions the expression of galectin-3 shifts from a predominant nuclear location to cytoplasmic and membrane expressions.In in vivo studies, galectin-3 was overexpressed in hypoxic areas of primary tumors and well-established metastases.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology (IPATIMUP), University of Porto, Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), University of Porto, Porto, Portugal; Faculty of Veterinary Medicine of the Lusophone University of Humanities and Technologies, Lisbon, Portugal.

ABSTRACT
The tumor microenvironment encompasses several stressful conditions for cancer cells such as hypoxia, oxidative stress and pH alterations. Galectin-3, a well-studied member of the beta-galactoside-binding animal family of lectins has been implicated in multiple steps of metastasis as cell-cell and cell-ECM adhesion, promotion of angiogenesis, cell proliferation and resistance to apoptosis. However, both its aberrantly up- and down-regulated expression was observed in several types of cancer. Thus, the mechanisms that regulate galectin-3 expression in neoplastic settings are not clear. In order to demonstrate the putative role of hypoxia in regulating galectin-3 expression in canine mammary tumors (CMT), in vitro and in vivo studies were performed. In malignant CMT cells, hypoxia was observed to induce expression of galectin-3, a phenomenon that was almost completely prevented by catalase treatment of CMT-U27 cells. Increased galectin-3 expression was confirmed at the mRNA level. Under hypoxic conditions the expression of galectin-3 shifts from a predominant nuclear location to cytoplasmic and membrane expressions. In in vivo studies, galectin-3 was overexpressed in hypoxic areas of primary tumors and well-established metastases. Tumor hypoxia thus up-regulates the expression of galectin-3, which may in turn increase tumor aggressiveness.

No MeSH data available.


Related in: MedlinePlus