Two-dimensional vs. three-dimensional in vitro tumor migration and invasion assays.

Motility and invasion are key hallmarks that distinguish benign from malignant tumors, enabling cells to cross tissue boundaries, disseminate in blood and lymph and establish metastases at distant sites. Similar properties are also utilized by activated endothelial cells during tumor-induced angiogenesis. It is now appreciated that these processes might provide a rich source of novel molecular targets with the potential for inhibitors to restrain both metastasis and neoangiogenesis. Such therapeutic strategies require assays that can rapidly and quantitatively measure cell movement and the ability to traverse physiological barriers. The need for high-throughput, however, must be balanced by assay designs that accommodate, as far as possible, the complexity of the in vivo tumor microenvironment. This chapter aims to give an overview of some commonly used migration and invasion assays to aid in the selection of a balanced portfolio of techniques for the rapid and accurate evaluation of novel therapeutic agents.