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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

Protein and mRNA galectin-3 expression are up regulated in tumor cells surrounding necrotic areas of CMT-U27 mice xenografts.Female N: NIHY(s)II-nu/nu mice were inoculated subcutaneously in the mammary fat pad with a suspension of 106 cells of the malignant CMT-U27 cell line. Primary tumors and metastases were collected at different times after inoculation. (A) Immunohistochemistry was performed to study galectin-3 and GLUT-1 expression (brown color) using M3/38 anti-galectin-3 and anti-GLUT-1 antibodies. Galectin-3 and GLUT-1 were overexpressed in viable tumor cells surrounding necrosis. (B) Galectin-3 was also overexpressed in lung micro metastases (C) Galectin-3 mRNA expression was detected in situ using a set of Stellaris RNA fluorescence in situ hybridization (FISH) probes in the cytoplasm of cells surrounding necrotic areas in CMT-U27 primary tumor xenografts. Nucleus were stained by DAPI. Each red spot corresponds to a single galectin-3 mRNA molecule.
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pone.0134458.g005: Protein and mRNA galectin-3 expression are up regulated in tumor cells surrounding necrotic areas of CMT-U27 mice xenografts.Female N: NIHY(s)II-nu/nu mice were inoculated subcutaneously in the mammary fat pad with a suspension of 106 cells of the malignant CMT-U27 cell line. Primary tumors and metastases were collected at different times after inoculation. (A) Immunohistochemistry was performed to study galectin-3 and GLUT-1 expression (brown color) using M3/38 anti-galectin-3 and anti-GLUT-1 antibodies. Galectin-3 and GLUT-1 were overexpressed in viable tumor cells surrounding necrosis. (B) Galectin-3 was also overexpressed in lung micro metastases (C) Galectin-3 mRNA expression was detected in situ using a set of Stellaris RNA fluorescence in situ hybridization (FISH) probes in the cytoplasm of cells surrounding necrotic areas in CMT-U27 primary tumor xenografts. Nucleus were stained by DAPI. Each red spot corresponds to a single galectin-3 mRNA molecule.

Mentions: Nude mice solid tumor xenografts often display necrosis, presumably due to the existence of highly hypoxic areas [39]. To evaluate the existence of such hypoxic areas and whether this would also influence galectin-3 expression in vivo, we inoculated the CMT-U27 cell line into the mammary fat pad of female nude mice and allowed the tumors to grow until they reached approximately 1000 mm3. Galectin-3 and GLUT-1 (hypoxia marker) expressions were assessed by immunohistochemistry in the tumor xenografts. Large necrotic areas were found and appear to be oxygen deprived as evidenced by GLUT-1 overexpression. High levels of galectin-3 expression were found in tumor areas surrounding necrotic tissue (Fig 5A) as well as in lung micro metastases (Fig 5B). To determine the presence and abundance of galectin-3 mRNA in CMT-U27 xenograft tumor cells surrounding necrosis, FISH was performed. Galectin-3 mRNA was found to be increased in cells surrounding necrotic areas (Fig 5C).


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)

Protein and mRNA galectin-3 expression are up regulated in tumor cells surrounding necrotic areas of CMT-U27 mice xenografts.Female N: NIHY(s)II-nu/nu mice were inoculated subcutaneously in the mammary fat pad with a suspension of 106 cells of the malignant CMT-U27 cell line. Primary tumors and metastases were collected at different times after inoculation. (A) Immunohistochemistry was performed to study galectin-3 and GLUT-1 expression (brown color) using M3/38 anti-galectin-3 and anti-GLUT-1 antibodies. Galectin-3 and GLUT-1 were overexpressed in viable tumor cells surrounding necrosis. (B) Galectin-3 was also overexpressed in lung micro metastases (C) Galectin-3 mRNA expression was detected in situ using a set of Stellaris RNA fluorescence in situ hybridization (FISH) probes in the cytoplasm of cells surrounding necrotic areas in CMT-U27 primary tumor xenografts. Nucleus were stained by DAPI. Each red spot corresponds to a single galectin-3 mRNA molecule.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0134458.g005: Protein and mRNA galectin-3 expression are up regulated in tumor cells surrounding necrotic areas of CMT-U27 mice xenografts.Female N: NIHY(s)II-nu/nu mice were inoculated subcutaneously in the mammary fat pad with a suspension of 106 cells of the malignant CMT-U27 cell line. Primary tumors and metastases were collected at different times after inoculation. (A) Immunohistochemistry was performed to study galectin-3 and GLUT-1 expression (brown color) using M3/38 anti-galectin-3 and anti-GLUT-1 antibodies. Galectin-3 and GLUT-1 were overexpressed in viable tumor cells surrounding necrosis. (B) Galectin-3 was also overexpressed in lung micro metastases (C) Galectin-3 mRNA expression was detected in situ using a set of Stellaris RNA fluorescence in situ hybridization (FISH) probes in the cytoplasm of cells surrounding necrotic areas in CMT-U27 primary tumor xenografts. Nucleus were stained by DAPI. Each red spot corresponds to a single galectin-3 mRNA molecule.
Mentions: Nude mice solid tumor xenografts often display necrosis, presumably due to the existence of highly hypoxic areas [39]. To evaluate the existence of such hypoxic areas and whether this would also influence galectin-3 expression in vivo, we inoculated the CMT-U27 cell line into the mammary fat pad of female nude mice and allowed the tumors to grow until they reached approximately 1000 mm3. Galectin-3 and GLUT-1 (hypoxia marker) expressions were assessed by immunohistochemistry in the tumor xenografts. Large necrotic areas were found and appear to be oxygen deprived as evidenced by GLUT-1 overexpression. High levels of galectin-3 expression were found in tumor areas surrounding necrotic tissue (Fig 5A) as well as in lung micro metastases (Fig 5B). To determine the presence and abundance of galectin-3 mRNA in CMT-U27 xenograft tumor cells surrounding necrosis, FISH was performed. Galectin-3 mRNA was found to be increased in cells surrounding necrotic areas (Fig 5C).

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