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Expression and functions of galectin-7 in human and murine melanomas.

Biron-Pain K, Grosset AA, Poirier F, Gaboury L, St-Pierre Y - PLoS ONE (2013)

Bottom Line: Using the experimental melanoma B16F1 cell line, we found that melanoma cells can express galectin-7 at the primary tumor site and in lung metastasis.Overexpression of galectin-7, however, was insufficient to modulate the growth of tumors induced by the subcutaneous injection of B16F1 cells.It also failed to modulate the dissemination of B16F1 cells to the lung.

View Article: PubMed Central - PubMed

Affiliation: INRS-Institut Armand-Frappier, Laval, Québec, Canada.

ABSTRACT
The identification of galectin-7 as a p53-induced gene and its ability to induce apoptosis in many cell types support the hypothesis that galectin-7 has strong antitumor activity. This has been well documented in colon cancer. However, in some cases, such as breast cancer and lymphoma, its high expression level correlates with aggressive subtypes of cancer, suggesting that galectin-7 may have a dual role in cancer progression. In fact, in breast cancer, overexpression of galectin-7 alone is sufficient to promote metastasis to the bone and lung. In the present work, we investigated the expression and function of galectin-7 in melanoma. An analysis of datasets obtained from whole-genome profiling of human melanoma tissues revealed that galectin-7 mRNA was detected in more than 90% of biopsies of patients with nevi while its expression was more rarely found in biopsies collected from patients with malignant melanoma. This frequency, however, was likely due to the presence of normal epidermis tissues in biopsies, as shown our studies at the protein level by immunohistochemical analysis. Using the experimental melanoma B16F1 cell line, we found that melanoma cells can express galectin-7 at the primary tumor site and in lung metastasis. Moreover, we found that overexpression of galectin-7 increased the resistance of melanoma cells to apoptosis while inducing de novo egr-1 expression. Overexpression of galectin-7, however, was insufficient to modulate the growth of tumors induced by the subcutaneous injection of B16F1 cells. It also failed to modulate the dissemination of B16F1 cells to the lung.

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Validation of B16F1 transfectants overexpressing luciferase and/or galectin-7.A) RT-PCR analysis for galectin-7 mRNA expression in transfectant cells overexpressing galectin-7 with or without luciferase in comparison with a control B16F1 cell line (F1). The aggressive murine lymphoma cell line S19 (+) was used as a positive control. Actin was used as a loading and specificity control. B) Luciferase assay of three B16F1 transfectant cell lines overexpressing luciferase and cotransfected with pRc-CMV2-galectin-7 in comparison with the control B16F1 cell line. C) Confocal microscopy for galectin-7 in control B16F1 cells (iii) and galectin-7 transfectant cells (G7#5) (iv); these cells were also visualized (i, ii).
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pone-0063307-g003: Validation of B16F1 transfectants overexpressing luciferase and/or galectin-7.A) RT-PCR analysis for galectin-7 mRNA expression in transfectant cells overexpressing galectin-7 with or without luciferase in comparison with a control B16F1 cell line (F1). The aggressive murine lymphoma cell line S19 (+) was used as a positive control. Actin was used as a loading and specificity control. B) Luciferase assay of three B16F1 transfectant cell lines overexpressing luciferase and cotransfected with pRc-CMV2-galectin-7 in comparison with the control B16F1 cell line. C) Confocal microscopy for galectin-7 in control B16F1 cells (iii) and galectin-7 transfectant cells (G7#5) (iv); these cells were also visualized (i, ii).

Mentions: Because overexpression of galectin-7 is known to regulate tumor growth and metastasis in multiple tumor cell types, we next investigated whether galectin-7 could modulate the growth of primary tumors and the dissemination of metastasis. For this purpose, we generated a series of stable B16 transfectants constitutively expressing galectin-7 at both the mRNA and protein levels (Fig. 3). The transfectants were also co-transfected with an expression vector encoding the firefly luciferase gene to facilitate in vivo follow-up of metastases to the lung. As previously reported, galectin-7 expression was restricted to the intracellular compartment and was not detected in the cultured supernatant of B16 transfectants (Fig. 3c and Figure S2).


Expression and functions of galectin-7 in human and murine melanomas.

Biron-Pain K, Grosset AA, Poirier F, Gaboury L, St-Pierre Y - PLoS ONE (2013)

Validation of B16F1 transfectants overexpressing luciferase and/or galectin-7.A) RT-PCR analysis for galectin-7 mRNA expression in transfectant cells overexpressing galectin-7 with or without luciferase in comparison with a control B16F1 cell line (F1). The aggressive murine lymphoma cell line S19 (+) was used as a positive control. Actin was used as a loading and specificity control. B) Luciferase assay of three B16F1 transfectant cell lines overexpressing luciferase and cotransfected with pRc-CMV2-galectin-7 in comparison with the control B16F1 cell line. C) Confocal microscopy for galectin-7 in control B16F1 cells (iii) and galectin-7 transfectant cells (G7#5) (iv); these cells were also visualized (i, ii).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3643947&req=5

pone-0063307-g003: Validation of B16F1 transfectants overexpressing luciferase and/or galectin-7.A) RT-PCR analysis for galectin-7 mRNA expression in transfectant cells overexpressing galectin-7 with or without luciferase in comparison with a control B16F1 cell line (F1). The aggressive murine lymphoma cell line S19 (+) was used as a positive control. Actin was used as a loading and specificity control. B) Luciferase assay of three B16F1 transfectant cell lines overexpressing luciferase and cotransfected with pRc-CMV2-galectin-7 in comparison with the control B16F1 cell line. C) Confocal microscopy for galectin-7 in control B16F1 cells (iii) and galectin-7 transfectant cells (G7#5) (iv); these cells were also visualized (i, ii).
Mentions: Because overexpression of galectin-7 is known to regulate tumor growth and metastasis in multiple tumor cell types, we next investigated whether galectin-7 could modulate the growth of primary tumors and the dissemination of metastasis. For this purpose, we generated a series of stable B16 transfectants constitutively expressing galectin-7 at both the mRNA and protein levels (Fig. 3). The transfectants were also co-transfected with an expression vector encoding the firefly luciferase gene to facilitate in vivo follow-up of metastases to the lung. As previously reported, galectin-7 expression was restricted to the intracellular compartment and was not detected in the cultured supernatant of B16 transfectants (Fig. 3c and Figure S2).

Bottom Line: Using the experimental melanoma B16F1 cell line, we found that melanoma cells can express galectin-7 at the primary tumor site and in lung metastasis.Overexpression of galectin-7, however, was insufficient to modulate the growth of tumors induced by the subcutaneous injection of B16F1 cells.It also failed to modulate the dissemination of B16F1 cells to the lung.

View Article: PubMed Central - PubMed

Affiliation: INRS-Institut Armand-Frappier, Laval, Québec, Canada.

ABSTRACT
The identification of galectin-7 as a p53-induced gene and its ability to induce apoptosis in many cell types support the hypothesis that galectin-7 has strong antitumor activity. This has been well documented in colon cancer. However, in some cases, such as breast cancer and lymphoma, its high expression level correlates with aggressive subtypes of cancer, suggesting that galectin-7 may have a dual role in cancer progression. In fact, in breast cancer, overexpression of galectin-7 alone is sufficient to promote metastasis to the bone and lung. In the present work, we investigated the expression and function of galectin-7 in melanoma. An analysis of datasets obtained from whole-genome profiling of human melanoma tissues revealed that galectin-7 mRNA was detected in more than 90% of biopsies of patients with nevi while its expression was more rarely found in biopsies collected from patients with malignant melanoma. This frequency, however, was likely due to the presence of normal epidermis tissues in biopsies, as shown our studies at the protein level by immunohistochemical analysis. Using the experimental melanoma B16F1 cell line, we found that melanoma cells can express galectin-7 at the primary tumor site and in lung metastasis. Moreover, we found that overexpression of galectin-7 increased the resistance of melanoma cells to apoptosis while inducing de novo egr-1 expression. Overexpression of galectin-7, however, was insufficient to modulate the growth of tumors induced by the subcutaneous injection of B16F1 cells. It also failed to modulate the dissemination of B16F1 cells to the lung.

Show MeSH
Related in: MedlinePlus