Atomic Force Microscopy Reveals a Role for Endothelial Cell ICAM-1 Expression in Bladder Cancer Cell Adherence

Abstract

Cancer metastasis is a complex process involving cell-cell interactions mediated by cell adhesive molecules. In this study we determine the adhesion strength between an endothelial cell monolayer and tumor cells of different metastatic potentials using Atomic Force Microscopy. We show that the rupture forces of receptor-ligand bonds increase with retraction speed and range between 20 and 70 pN. It is shown that the most invasive cell lines (T24, J82) form the strongest bonds with endothelial cells. Using ICAM-1 coated substrates and a monoclonal antibody specific for ICAM-1, we demonstrate that ICAM-1 serves as a key receptor on endothelial cells and that its interactions with ligands expressed by tumor cells are correlated with the rupture forces obtained with the most invasive cancer cells (T24, J82). For the less invasive cancer cells (RT112), endothelial ICAM-1 does not seem to play any role in the adhesion process. Moreover, a detailed analysis of the distribution of rupture forces suggests that ICAM-1 interacts preferentially with one ligand on T24 cancer cells and with two ligands on J82 cancer cells. Possible counter receptors for these interactions are CD43 and MUC1, two known ligands for ICAM-1 which are expressed by these cancer cells.

Role of liver ICAM-1 in metastasis

“…IL-8 and IL-6 facilitate tumor cell attachment to endothelial cells and enhance vascular permeability, as observed in models of brain and lung metastasis (53,54). Additionally, a previous study used atomic-force microscopy to show that endothelial ICAM-1 mediates the adhesion of different invasive bladder cancer cells to endothelial cells (24). In line with these results, a reduction in ICAM-1 expression via siRNAs or by using ICAM-1-blocking antibodies significantly decreased the adhesion of fibrosarcoma cells to ECV304 human endothelial cells in vitro (55), and of C26 CRC cells to LSECs in vivo (56).…”

“…Several adhesion molecules, such as E-selectin, vascular cellular adhesion molecule (VCAM)-1 and ICAM-1, exhibit increased expression in the liver during metastatic invasion (22). Among them, ICAM-1 mediates several stages of the metastatic cascade, including the adhesion of tumor cells to the endothelial wall (23)(24)(25), endothelial cell activation of pro-metastatic signaling pathways (26)(27)(28), tumor cell extravasation (23,29), the recruitment of immune cell populations (28,30,31), the pro-angiogenic response (32) and the transdifferentiation of stellate cells during the desmoplastic response (33,34). This review will focus on the role of ICAM-1 during the different events of the metastatic cascade that drives colonization of the liver by circulating tumor cells, and how it modulates the liver microenvironment to facilitate metastasis.…”

The impact of hyperglycemia on adhesion between endothelial and cancer cells revealed by single‐cell force spectroscopy

“…Second, to attach a living cancer cell to the functionalized cantilever, we detached the A549 cells from culture flask by using d‐PBS (PBS without Ca 2+ and Mg 2+ ions). Strongly adhered cells were removed by using low concentration of trypsin solution 0.001% . To block the effect of trypsin, the cells were suspended in growing medium supplemented by 20% of BSA and maintained at 37°C in an incubator (5% CO 2 ) for 1 hour.…”

“…Strongly adhered cells were removed by using low concentration of trypsin solution 0.001%. 32 To block the effect of trypsin, the cells were suspended in growing medium supplemented by 20% of BSA and maintained at 37°C in an incubator (5% CO 2 ) for 1 hour. We noted that for longer incubation times, A549 cells tend to reattach to the Petri dish.…”

“…In particular, by attaching a cancer cell to the tip of AFM, Reeves et al characterized tumor cell adhesion molecules and determined active tumor cell interactions with human bone marrow endothelial cells. Using a similar method, Laurent et al revealed the role of ICAM‐1 expression in bladder cancer cell adherence to ECs.…”