Biogenesis of invadopodia and their cellular functions

Cancer cells degrade the extracellular matrix (ECM) in the basement membrane and blood vessel walls to emigrate and invade from original to peripheral tissues. This invasion of cells through ECM layers is a key step not only in tumor metastasis but also in other processes such as inflammation and development. All of them seem to be facilitated by the formation of small cellular protrusions of localized protease activity, termed podosomes in non-malignant cells and invadopodia in cancer cells. Understanding the mechanisms that lead to functional invadopodia is nowadays a subject of intense study. Herein, a brief overview of the molecular components and regulators of invadopodia will be provided. In this review we will summarize recent achievements and the latest methods of visualizing invadopodia formation and functions, with a strong emphasis on advanced microscopy approaches.