Invadopodia

Overview

Diagram of an invadopodium structure.

Invadopodia are specialized protrusions of the plasma membrane found in cancer cells and other cell types that are involved in the degradation of the extracellular matrix (ECM). These structures play a crucial role in cancer metastasis, allowing tumor cells to invade surrounding tissues and spread to distant sites in the body.

Structure

Invadopodia are actin-rich protrusions that extend from the cell surface. They are composed of a core of actin filaments surrounded by a complex of proteins that regulate their formation and function. Key components of invadopodia include:

• Actin
• Cortactin
• Coactosin
• Arp2/3 complex
• MT1-MMP (Membrane type 1 matrix metalloproteinase)

These components work together to form a dynamic structure capable of remodeling the ECM.

Function

The primary function of invadopodia is the degradation of the ECM, which is essential for cell invasion. Invadopodia achieve this by concentrating proteolytic enzymes, such as matrix metalloproteinases (MMPs), at their tips. This localized degradation of the ECM facilitates the invasion of cancer cells into surrounding tissues.

Formation

The formation of invadopodia is a complex process that involves multiple signaling pathways. Key signaling molecules involved in invadopodia formation include:

• Src kinase
• PI3K (Phosphoinositide 3-kinase)
• Rho GTPases

These signaling pathways regulate the assembly of actin filaments and the recruitment of proteolytic enzymes to the invadopodia.

Role in Cancer

Invadopodia are particularly important in the context of cancer, where they contribute to the invasive and metastatic potential of tumor cells. By degrading the ECM, invadopodia enable cancer cells to breach tissue barriers and enter the bloodstream or lymphatic system, leading to the spread of cancer to distant organs.

Research and Therapeutic Implications

Understanding the molecular mechanisms underlying invadopodia formation and function is a major area of research. Targeting invadopodia and their associated signaling pathways holds potential for the development of novel anti-metastatic therapies.

Related pages

• Cancer metastasis
• Extracellular matrix
• Matrix metalloproteinase
• Actin cytoskeleton