Difference Between Cell Migration and Invasion

The main difference between cell migration and invasion is that cell migration is the directed movement of cells in response to a chemical or mechanical response whereas invasion is the ability of cells to become motile and to navigate through the extracellular matrix within a tissue or to infiltrate neighboring tissues. Furthermore, cell migration is important for tissue formation during embryonic development, wound healing, and immune response while invasion is important in tumor progression. 

Cell migration and invasion are two types of processes undergone by cells in multicellular organisms. However, both processes are also important in disease conditions as well. 

Key Areas Covered 

1. What is Cell Migration
     – Definition, Process, Importance
2. What is Invasion
     – Definition, Process, Importance
3. What are the Similarities Between Cell Migration and Invasion
     – Outline of Common Features
4. What is the Difference Between Cell Migration and Invasion
     – Comparison of Key Differences

Key Terms 

Cancer Development, Cell Migration, Extracellular Matrix, Invasion, Tissue Formation

What is Cell Migration 

Cell migration is the regular movement of cells in multicellular organisms. It is a major process in the development and maintenance of the body of multicellular organisms. Moreover, the migration of cells is a directional process, which occurs in response to either a chemical or mechanical stimulus. Generally, it is important for tissue formation during embryonic development. Therefore, it is responsible for the various morphogenetic events in the developing embryo. For example, during gastrulation, the three germ layers form as a result of a series of cell migration steps that occur in the inner cell mass. Consequently, the cells in these germ layers further migrate into their target locations in order to undergo specialization, forming tissues and organs. 

Figure 1: Gastrulation

Furthermore, cell migration plays a key function in the renewal and repair of tissues in adults. Here, cells from the underlying tissue layers migrate to tissues with old or damaged cells in order to replace them. Therefore, migration of cells is critical in maintaining tissue integrity while allowing wound healing. On the other hand, different cells in the immune system, including phagocytes, macrophages, and neutrophils, migrate from the bloodstream to the infected tissues in order to trigger an immune response. However, undesirable cell migration can cause various pathological conditions, including tumor formation, vascular disease, inflammatory diseases, etc.  

What is Invasion 

Invasion is an active process of direct extension and penetration of cells into neighboring tissues through the extracellular matrix. Generally, the penetration of cells in a tumor is the key process responsible for cancer invasion into neighboring tissues. Moreover, various factors such as the extracellular matrix, junction proteins, cytokines, the expression of proteases as well as the alteration of cellular dynamics facilitate tumor cell invasion. Thus, the two major events of cell invasion include the degradation of the extracellular matrix and proteolysis. Metastasis is another stage of cancer development, spreading the cells in a tumor either through the circulatory or lymphatic system.

Figure 2: Cancer Cell Invasion Patterns

Due to this specific requirement of invasion to penetrate extracellular matrix, cell invasion assays have to perform in a special way, in addition to assays for cell migration. Generally, in cell migration assays, a semi-solid matrix of either gelatin or agar serves as the medium for the migration of cells. In contrast, in invasion assays, a filter with molecules resembling the molecules in the extracellular matrix is used to separate the chambers on the way of cell movement.  

Similarities Between Cell Migration and Invasion  

• Cell migration and invasion are two types of processes undergone by cells in multicellular organisms. 
• They are important in the development of organisms for tissue formation during embryonic development.
• Moreover,  they are important in disease formation as well. 

Difference Between Cell Migration and Invasion 

Definition 

Cell migration refers to the directed movement of cells in response to a chemical or mechanical response while invasion refers to the ability of cells to become motile and to navigate through the extracellular matrix within a tissue or to infiltrate neighboring tissues. 

Significance 

Another difference between cell migration and invasion is that cell migration is a normal cell movement while invasion is a process of actively invading surrounding tissues.  

Process 

Moreover, cell migration is a multi-step process while invasion proceeds through ECM degradation and proteolysis. 

Importance 

Cell migration is important for tissue formation during embryonic development, wound healing, and immune response while invasion is important in tumor progression. 

Types of Assays  

Agar-plate techniques are examples of cell migration assays while two-chamber techniques including Boyden chamber, bridge chambers, and capillary techniques are examples of invasion assays.  

Principle of Assays 

Furthermore, cell migration assays enable quantification of in vitro cell migration towards a chemical concentration gradient (chemotaxis) or ECM protein gradient (haptotaxis) while invasion assays enable quantification of in vitro cell invasion through a basement membrane ECM protein or a layer of cells such as endothelial cells.  

Conclusion 

Cell migration is the normal movement of cells in multicellular organisms. It is important for tissue formation during embryonic development, wound healing, and immune response. However, an invasion is an active process of cell movement, occurring through the extra-cellular matrix. Therefore, ECM degradation and proteolysis are two key processes of cell invasion. Furthermore, invasion is an important process of tumor progression into metastasis. However, the main difference between cell migration and invasion is the type of cell movement and their importance. 

References:

1. “What Is Cell Migration?” MBInfo, National University of Singapore, 6 July 2018, Available Here.
2. “Cell Migration, Invasion and Wound Healing.” Cell Biolabs, Cell Biolabs, Inc., Available Here.

Image Courtesy:

1. “Blastula” By Abigail Pyne – Own work (Public Domain) via Commons Wikimedia  
2. “Patterns of cancer cell invasion” By N. V. Krakhmal, et al (2015). “Cancer Invasion: Patterns and Mechanisms.”. Acta Naturae 7 (2): 17-28.(CC BY 4.0) via Commons Wikimedia