Invadopodia

Invadopodia are dynamic actin-rich protrusions that cells extend to degrade and penetrate the extracellular matrix (ECM). These specialized structures are crucial for various biological processes, including cell migration, tissue remodeling, and invasion. They are characterized by a dense core of actin filaments, often stabilized by proteins like Arp2/3 complex and formins, and are surrounded by a membrane.

The formation and function of invadopodia are tightly regulated. Key signaling pathways involving tyrosine kinases, small GTPases like Rho and Cdc42, and adapter proteins are essential for their assembly. A hallmark of invadopodia is their ability to recruit and activate matrix-degrading enzymes, most notably matrix metalloproteinases (MMPs), to the cell surface. These enzymes break down the surrounding ECM, creating a path for the cell to move through.

Invadopodia are prominently implicated in cancer metastasis. Cancer cells often exhibit increased invadopodia formation, which facilitates their invasion into surrounding tissues and subsequent dissemination through the bloodstream or lymphatic system. This invasive capability is a critical step in the development of secondary tumors. Beyond cancer, invadopodia also play roles in normal physiological processes such as embryonic development, wound healing, and immune cell function, where controlled ECM degradation and cell migration are required. Research into invadopodia aims to understand their complex molecular machinery and to explore therapeutic strategies targeting their aberrant activity, particularly in the context of cancer.