The role of tumor cell adhesion as an important factor in formation of distant colorectal metastasis

PURPOSE: The interactions of blood-borne colorectal carcinoma cells with vascular endothelium are important during hematogenous formation of distant metastases. To adhere to the vessel wall, circulating carcinoma cells that come into contact with the microvasculature must resist the attractive forces of the flow of plasma and other circulating cells that tend to detach them from the wall. METHODS: Hydrodynamic adhesion assays have been introduced to mimic the microcirculation and investigate cell adhesion under flow conditions. Different aspects of colorectal cancer cell adhesion during hematogenous formation of distant metastases are summarized and discussed in this review. RESULTS: Adhesion of colorectal carcinoma cells to endothelial cells and extracellular matrix is influenced by the presence of fluid flow. Shear forces alone are able to induce signal transduction events in these cells that result in cell activation and modification of adhesive behavior. CONCLUSIONS: Consideration of fluid dynamics of circulating colorectal cancer cell movement in the microcirculation leads to new knowledge of in vivo processes that are involved in tumor cell adhesion to the vessel wall in host organs. Shear forces have been found to influence adhesive properties of colorectal carcinoma cells to endothelial cells and underlying subendothelial extracellular matrix. Understanding the complex processes involved in tumor cell adhesion may result in the development of novel therapeutic strategies.