ABSTRACT
We describe that galectin-1 (gal-1) is a receptor for the angiogenesis inhibitor anginex, and that the protein is crucial for tumor angiogenesis. gal-1 is overexpressed in endothelial cells of different human tumors. Expression knockdown in cultured endothelial cells inhibits cell proliferation and migration. The importance of gal-1 in angiogenesis is illustrated in the zebrafish model, where expression knockdown results in impaired vascular guidance and growth of dysfunctional vessels. The role of gal-1 in tumor angiogenesis is demonstrated in gal-1-null mice, in which tumor growth is markedly impaired because of insufficient tumor angiogenesis. Furthermore, tumor growth in gal-1-null mice no longer responds to antiangiogenesis treatment by anginex. Thus, gal-1 regulates tumor angiogenesis and is a target for angiostatic cancer therapy.
Subject(s)
Galectin 1/metabolism , Neoplasms/blood supply , Neoplasms/metabolism , Animals , Cell Movement , Cell Proliferation , Cells, Cultured , Disease Progression , Endothelial Cells/metabolism , Endothelial Cells/pathology , Galectin 1/deficiency , Galectin 1/genetics , Gene Expression Regulation, Neoplastic , Humans , Mice , Mice, Knockout , Neoplasm Transplantation , Neoplasms/genetics , Neoplasms/therapy , Peptides , Protein Binding , Proteins/metabolism , ZebrafishABSTRACT
To study the relationship between the angiogenic profile and leukocyte infiltration of tumors, single cell suspensions of archival frozen medullary and ductal breast cancer tissues were analyzed by flow cytometry. The amount of leukocytes and endothelial cells was measured, as well as the expression of intercellular adhesion molecule-1 (ICAM-1) on the endothelial cell fraction. A significantly higher number (3.2-fold) of infiltrating leukocytes was observed in medullary carcinoma. The composition of this infiltrate was similar to that seen in ductal carcinomas. The more intense infiltrate was explained by the approximately 3-fold enhanced endothelial ICAM-1 expression in medullary carcinoma. The angiogenic profile of all tumors was assessed by quantitative real-time reverse transcription-PCR analysis. Vascular endothelial growth factor (VEGF)-C and VEGF-D, but not VEGF-A, basic fibroblast growth factor, placental growth factor, and angiopoietins 1, 2, and 3 showed a relatively higher level of expression in ductal carcinoma than in medullary carcinoma. In vitro, both VEGF-C and VEGF-D were found to decrease endothelial ICAM-1 expression in the presence of basic fibroblast growth factor. These data suggest that in vivo angiogenic stimuli prevent the formation of an effective leukocyte infiltrate in tumors by suppressing endothelial ICAM-1 expression.
Subject(s)
Breast Neoplasms/blood supply , Breast Neoplasms/pathology , Leukocytes/cytology , Neovascularization, Pathologic , Carcinoma/pathology , Cell Separation , Cells, Cultured , DNA Primers/chemistry , DNA, Complementary/metabolism , Down-Regulation , Endothelium, Vascular/cytology , Endothelium, Vascular/metabolism , Female , Flow Cytometry , Humans , Immunohistochemistry , Intercellular Adhesion Molecule-1/biosynthesis , Intercellular Adhesion Molecule-1/metabolism , Leukocyte Common Antigens/biosynthesis , Leukocytes/metabolism , Lymphatic Metastasis , RNA/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Time Factors , Umbilical Veins/cytology , Vascular Endothelial Growth Factor A/biosynthesis , Vascular Endothelial Growth Factor C/biosynthesis , Vascular Endothelial Growth Factor D/biosynthesisABSTRACT
Human antibodies selectively targeting angiogenic vessels hold great promise for the immunotherapy of human malignancies and can help to elucidate the molecular mechanisms regulating angiogenesis. By selecting a large antibody phage display library on proliferating stimulated HUVEC, we have isolated 15 human antibodies that bind to HUVEC in flow cytometric analysis, 11 of which target the vasculature of colorectal carcinomas as demonstrated by immunohistochemical analysis. The four most specific antibodies, TEM-A, TEM-C, TEM-M and TEM-Q, also stain the vasculature of a series of carcinomas derived from liver, ovary, kidney, bladder, lung and breast, and either react weakly or not all with the vasculature of corresponding normal tissues. All four antibodies react with the vasculature of endometrium, but only TEM-M and TEM-Q react with the vasculature of placenta. As shown by non-reducing western blot analysis, 9/15 of the antibodies recognize either one or two distinct bands on HUVEC cell lysates, with molecular weights of 175 and/or 110-125 kDa. Antibodies identified by this approach may be used for the identification of new markers of angiogenesis and/or tumor vasculature. The selected antibodies may prove useful as new prognostic markers, for in vivo tumor imaging purposes and for further development of targeted therapies.
