Cell and molecular biology of invadopodia.

The controlled degradation of the extracellular matrix is crucial in physiological and pathological cell invasion alike. In vitro, degradation occurs at specific sites where invasive cells make contact with the extracellular matrix via specialized plasma membrane protrusions termed invadopodia. Considerable progress has been made in recent years toward understanding the basic molecular components and their ultrastructural features; generating substantial interest in invadopodia as a paradigm to study the complex interactions between the intracellular trafficking, signal transduction, and cytoskeleton regulation machineries. The next level will be to understand whether they may also represent valid biological targets to help advance the anticancer drug discovery process. Current knowledge will be reviewed here together with some of the most important open questions in invadopodia biology.