Expression and functions of galectin-7 in ovarian cancer

Abstract

// Marilyne Labrie 1 , Maria Claudia Vladoiu 1 , Andrée-Anne Grosset 1 , Louis Gaboury 2 and Yves St-Pierre 1 1 INRS-Institut Armand-Frappier, Laval, Québec, Canada 2 Institute for Research in Immunology and Cancer, Downtown Station, Montréal, Québec, Canada Correspondence: Yves St-Pierre, email: // Keywords : galectin-7, ovarian cancer, immunosupression, p53, MMP-9 Received : June 09, 2014 Accepted : July 31, 2014 Published : July 31, 2014 Abstract There is a critical need to develop effective new strategies for diagnosis and treatment of ovarian cancer. In the present work, we investigated the expression of galectin-7 (gal-7) in epithelial ovarian cancer (EOC) cells and studied its functional relevance. Immunohistochemical analysis of gal-7 expression in tissue microarrays showed that while gal-7 was not detected in normal ovarian tissues, positive cytoplasmic staining of gal-7 was detected in epithelial cells in all EOC histological subtypes but was more frequent in high grade tumors and metastatic samples. Gal-7 expression correlated with a significant difference in the overall survival of patients with ovarian serous cystadenocarcinoma. Furthermore, using human EOC cell lines, we found that gal-7 expression was induced by mutant p53. Mechanistically, Matrigel invasion assays and live cell imaging showed that gal-7 increased the invasive behavior of ovarian cancer cells by inducing MMP-9 and increasing cell motility. EOC cells can also secrete gal-7. Recombinant human gal-7 kills Jurkat T cells and human peripheral T cells, suggesting that gal-7 also has immunosuppressive properties. Taken together, our study validates the clinical significance of gal-7 overexpression in ovarian cancer and provides a rationale for targeting gal-7 to improve the outcome of patients with this disease.