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Cancer cell invasion is enhanced by applied mechanical stimulation.

Menon S, Beningo KA - PLoS ONE (2011)

Bottom Line: We have discovered a significant difference in the extent of invasion in mechanically stimulated verses non-stimulated cell culture environments.Finally, we have found that the protein cofilin is needed to sense the mechanical stimuli that enhances invasion.We conclude that other types of mechanical signals in the tumor microenvironment, besides the rigidity, can enhance the invasive abilities of cancer cells in vitro.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America.

ABSTRACT
Metastatic cells migrate from the site of the primary tumor, through the stroma, into the blood and lymphatic vessels, finally colonizing various other tissues to form secondary tumors. Numerous studies have been done to identify the stimuli that drive the metastatic cascade. This has led to the identification of multiple biochemical signals that promote metastasis. However, information on the role of mechanical factors in cancer metastasis has been limited to the affect of compliance. Interestingly, the tumor microenvironment is rich in many cell types including highly contractile cells that are responsible for extensive remodeling and production of the dense extracellular matrix surrounding the cancerous tissue. We hypothesize that the mechanical forces produced by remodeling activities of cells in the tumor microenvironment contribute to the invasion efficiency of metastatic cells. We have discovered a significant difference in the extent of invasion in mechanically stimulated verses non-stimulated cell culture environments. Furthermore, this mechanically enhanced invasion is dependent upon substrate protein composition, and influenced by topography. Finally, we have found that the protein cofilin is needed to sense the mechanical stimuli that enhances invasion. We conclude that other types of mechanical signals in the tumor microenvironment, besides the rigidity, can enhance the invasive abilities of cancer cells in vitro. We further propose that in vivo, non-cancerous cells located within the tumor micro-environment may be capable of providing the necessary mechanical stimulus during the remodeling of the extracellular matrix surrounding the tumor.

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Related in: MedlinePlus

The mechanically enhanced invasion assay.A) A well is created in a 60 mm culture dish and filled with a type I collagen/fibronectin matrix containing 2 µm paramagnetic beads. Cells are seeded onto the surface of the matrix and either cultured outside of a magnetic field or cultured 1.5 cm above a rotating rare earth magnet. Upon stimulation, cells invade the matrix. B) 60 mm plate with a 20 mm hole drilled into it, with an activated coverslip glued to the bottom, creates a well for the matrix. C) The culture is suspended 1.5 cm above a rare earth magnet placed on an orbital shaker within a typical cell culture incubator. See the methods section for details.
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pone-0017277-g001: The mechanically enhanced invasion assay.A) A well is created in a 60 mm culture dish and filled with a type I collagen/fibronectin matrix containing 2 µm paramagnetic beads. Cells are seeded onto the surface of the matrix and either cultured outside of a magnetic field or cultured 1.5 cm above a rotating rare earth magnet. Upon stimulation, cells invade the matrix. B) 60 mm plate with a 20 mm hole drilled into it, with an activated coverslip glued to the bottom, creates a well for the matrix. C) The culture is suspended 1.5 cm above a rare earth magnet placed on an orbital shaker within a typical cell culture incubator. See the methods section for details.

Mentions: The goal of this study was to determine if applied mechanical stimulation, such as those simulating the re-modeling of the extracellular matrix, could enhance the process of invasion. To address our hypothesis, we designed a new assay system where mechanical stimulation could be applied in the absence of secreted biochemical factors. Our intention was to create an assay that used commercially available components, required standard equipment, provided control of biochemical and mechanical parameters, all in a framework that was optically compatible with an ordinary fluorescent microscope. We chose to use a type I collagen matrix commonly used for invasion assays, reasoning that the stroma is highly enriched in this extracellular matrix protein. Carboxylated fluorescent paramagnetic micro-beads were embedded within the matrix to provide mechanical stimulation. To produce a transient magnetic pull, without the need for a micron size electro-magnet, we rotated a rare earth magnet on a rotating mixer beneath the culture while the culture was suspended above the magnet (Figure 1A). The entire culture system can be maintained within a standard tissue culture incubator (Figure 1B, C).


Cancer cell invasion is enhanced by applied mechanical stimulation.

Menon S, Beningo KA - PLoS ONE (2011)

The mechanically enhanced invasion assay.A) A well is created in a 60 mm culture dish and filled with a type I collagen/fibronectin matrix containing 2 µm paramagnetic beads. Cells are seeded onto the surface of the matrix and either cultured outside of a magnetic field or cultured 1.5 cm above a rotating rare earth magnet. Upon stimulation, cells invade the matrix. B) 60 mm plate with a 20 mm hole drilled into it, with an activated coverslip glued to the bottom, creates a well for the matrix. C) The culture is suspended 1.5 cm above a rare earth magnet placed on an orbital shaker within a typical cell culture incubator. See the methods section for details.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040771&req=5

pone-0017277-g001: The mechanically enhanced invasion assay.A) A well is created in a 60 mm culture dish and filled with a type I collagen/fibronectin matrix containing 2 µm paramagnetic beads. Cells are seeded onto the surface of the matrix and either cultured outside of a magnetic field or cultured 1.5 cm above a rotating rare earth magnet. Upon stimulation, cells invade the matrix. B) 60 mm plate with a 20 mm hole drilled into it, with an activated coverslip glued to the bottom, creates a well for the matrix. C) The culture is suspended 1.5 cm above a rare earth magnet placed on an orbital shaker within a typical cell culture incubator. See the methods section for details.
Mentions: The goal of this study was to determine if applied mechanical stimulation, such as those simulating the re-modeling of the extracellular matrix, could enhance the process of invasion. To address our hypothesis, we designed a new assay system where mechanical stimulation could be applied in the absence of secreted biochemical factors. Our intention was to create an assay that used commercially available components, required standard equipment, provided control of biochemical and mechanical parameters, all in a framework that was optically compatible with an ordinary fluorescent microscope. We chose to use a type I collagen matrix commonly used for invasion assays, reasoning that the stroma is highly enriched in this extracellular matrix protein. Carboxylated fluorescent paramagnetic micro-beads were embedded within the matrix to provide mechanical stimulation. To produce a transient magnetic pull, without the need for a micron size electro-magnet, we rotated a rare earth magnet on a rotating mixer beneath the culture while the culture was suspended above the magnet (Figure 1A). The entire culture system can be maintained within a standard tissue culture incubator (Figure 1B, C).

Bottom Line: We have discovered a significant difference in the extent of invasion in mechanically stimulated verses non-stimulated cell culture environments.Finally, we have found that the protein cofilin is needed to sense the mechanical stimuli that enhances invasion.We conclude that other types of mechanical signals in the tumor microenvironment, besides the rigidity, can enhance the invasive abilities of cancer cells in vitro.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America.

ABSTRACT
Metastatic cells migrate from the site of the primary tumor, through the stroma, into the blood and lymphatic vessels, finally colonizing various other tissues to form secondary tumors. Numerous studies have been done to identify the stimuli that drive the metastatic cascade. This has led to the identification of multiple biochemical signals that promote metastasis. However, information on the role of mechanical factors in cancer metastasis has been limited to the affect of compliance. Interestingly, the tumor microenvironment is rich in many cell types including highly contractile cells that are responsible for extensive remodeling and production of the dense extracellular matrix surrounding the cancerous tissue. We hypothesize that the mechanical forces produced by remodeling activities of cells in the tumor microenvironment contribute to the invasion efficiency of metastatic cells. We have discovered a significant difference in the extent of invasion in mechanically stimulated verses non-stimulated cell culture environments. Furthermore, this mechanically enhanced invasion is dependent upon substrate protein composition, and influenced by topography. Finally, we have found that the protein cofilin is needed to sense the mechanical stimuli that enhances invasion. We conclude that other types of mechanical signals in the tumor microenvironment, besides the rigidity, can enhance the invasive abilities of cancer cells in vitro. We further propose that in vivo, non-cancerous cells located within the tumor micro-environment may be capable of providing the necessary mechanical stimulus during the remodeling of the extracellular matrix surrounding the tumor.

Show MeSH
Related in: MedlinePlus