Endothelial integrin α3β1 stabilizes carbohydrate-mediated tumor/endothelial cell adhesion and induces macromolecular signaling complex formation at the endothelial cell membrane

• Published in: Oncotarget 2014-03, Vol.5 (5), p.1382-1389
• Main Authors: Glinskii, Olga V, Li, Feng, Wilson, Landon S, Barnes, Stephen, Rittenhouse-Olson, Kate, Barchi, Jr, Joseph J, Pienta, Kenneth J, Glinsky, Vladislav V
• Format: Article
• Language: English
• Subjects: Antigens, Tumor-Associated, Carbohydrate - metabolism; Cell Adhesion - physiology; Cell Line, Tumor; Cell Membrane - chemistry; Cell Membrane - metabolism; Endothelial Cells - chemistry; Endothelial Cells - physiology; Galectin 3 - analysis; Galectin 3 - metabolism; Humans; Integrin alpha3beta1 - analysis; Integrin alpha3beta1 - metabolism; Macromolecular Substances - metabolism; Male; MAP Kinase Signaling System; Neoplasm Metastasis - physiopathology; Prostatic Neoplasms - metabolism; Research Paper; src-Family Kinases - analysis; src-Family Kinases - metabolism
• ISSN: 1949-2553; 1949-2553
• DOI: 10.18632/oncotarget.1837

Blood borne metastatic tumor cell adhesion to endothelial cells constitutes a critical rate-limiting step in hematogenous cancer metastasis. Interactions between cancer associated carbohydrate Thomsen-Friedenreich antigen (TF-Ag) and endothelium-expressed galectin-3 (Gal-3) have been identified as the leading molecular mechanism initiating tumor/endothelial cell adhesion in several types of cancer. However, it is unknown how these rather weak and transient carbohydrate/lectin mediated interactions are stabilized. Here, using Western blot and LC tandem mass spectrometry analyses of pull-downs utilizing TF-Ag loaded gold nanoparticles, we identified Gal-3, endothelial integrin α3β1, Src kinase, as well as 5 additional molecules mapping onto focal adhesion pathway as parts of the macromolecular complexes formed at the endothelial cell membranes downstream of TF-Ag/Gal-3 interactions. In a modified parallel flow chamber assay, inhibiting α3β1 integrin greatly reduced the strength of tumor/endothelial cell interactions without affecting the initial cancer cell adhesion. Further, the macromolecular complex induced by TF-Ag/Gal-3/α3β1 interactions activates Src kinase, p38, and ERK1/2, pathways in endothelial cells in a time- and α3β1-dependent manner. We conclude that, following the initial metastatic cell attachment to endothelial cells mediated by TF-Ag/Gal-3 interactions, endothelial integrin α3β1 stabilizes tumor/endothelial cell adhesion and induces the formation of macromolecular signaling complex activating several major signaling pathways in endothelial cells.