A structured framework of cytoskeletal proteins and noncentrosomal microtubules promotes the initiation and elongation of invadopodia.

Cancer deaths are largely attributed to the dissemination of cancer cells from a primary tumor to a secondary metastatic site. The metastatic cascade is initiated by cancer cell invasion that is facilitated by cytoskeletal remodeling to produce ventral cell protrusions, termed invadopodia, that degrade the extracellular matrix to promote motility. Conventional invadopodia studies rely on techniques with embedded cells in 3D matrices to observe and determine protein behavior, which often utilize immunolabeling strategies and struggle to visualize individual invadopodia, thereby limiting investigations of protein and invadopodia dynamics. Here, the design and utilization of an axial invasion chamber is described for live-cell imaging of elongating invadopodia in 3D. Results identify that cytoskeletal and microtubule-associated proteins within invadopodia exist in an organized framework, and determine the functional contribution by which noncentrosomal microtubules promote cancer cell invasion and migration.