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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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Upward Invasion Assay.A) HT1080 fibrosarcoma cells were seeded onto a collagen/fibronectin coated coverglass at the bottom of the well. After the cells had adhered, a type I collagen/fibronectin solution containing paramagnetic microbeads was overlaid onto the cells and allowed to polymerize. Cultures were either subjected to magnetic stimulation or grown outside the magnetic field. B) The magnet is rotated above the culture as cells start to invade up into the matrix. C) HT1080 cells seeded on a collagen-fibronectin coated coverslip and overlaid with a collagen/fibronectin matrix were cultured either in the presence or absence of a magnetic field. Percent invasion was calculated 24 and 48 hours following stimulation from three independent trials (15 fields were counted per culture). A difference in invasion (approx. 4–fold higher) between the stimulated cultures as compared to non-stimulated cultures was significant at 48 hours post-stimulation (P<0.005).
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pone-0017277-g004: Upward Invasion Assay.A) HT1080 fibrosarcoma cells were seeded onto a collagen/fibronectin coated coverglass at the bottom of the well. After the cells had adhered, a type I collagen/fibronectin solution containing paramagnetic microbeads was overlaid onto the cells and allowed to polymerize. Cultures were either subjected to magnetic stimulation or grown outside the magnetic field. B) The magnet is rotated above the culture as cells start to invade up into the matrix. C) HT1080 cells seeded on a collagen-fibronectin coated coverslip and overlaid with a collagen/fibronectin matrix were cultured either in the presence or absence of a magnetic field. Percent invasion was calculated 24 and 48 hours following stimulation from three independent trials (15 fields were counted per culture). A difference in invasion (approx. 4–fold higher) between the stimulated cultures as compared to non-stimulated cultures was significant at 48 hours post-stimulation (P<0.005).

Mentions: The dimensionality of the environment is known to influence cellular behavior. Specifically, HT1080 cells have been shown to change their migration speed and persistence in three dimensions [37]. In our initial experiments, the cells are seeded on top of the matrix, invading from the top downward, thus beginning in two-dimensions and moving into three. To address the influence of dimensionality on mechanical invasion we changed the orientation of the stimulus so the cells would invade upwards. To do this, we first seeded the cells onto collagen/fibronectin-coated coverslips before overlaying and polymerizing the collagen/fibronectin/magnetic bead solution over them (Figure 4A). The magnetic field was then applied to the top of the culture by rotating the magnet above the stationary culture (Figure 4B). After 24 hours of stimulation, we found the cells invaded just as well as they did when they were seeded on top of the matrices prior to stimulation (6% invasion in non-stimulated and 13% in stimulated cultures) (Figure 4B). However, we found by 48 hours the difference between non-stimulated invasion and stimulated invasion was even larger such that 12% of the cells invaded in non-stimulated versus 41% invasion in the stimulated cultures. Thus, an even greater enhancement of invasion occurs in the response to applied mechanical stimulation when the cells began in a three-dimensional environment.


Cancer cell invasion is enhanced by applied mechanical stimulation.

Menon S, Beningo KA - PLoS ONE (2011)

Upward Invasion Assay.A) HT1080 fibrosarcoma cells were seeded onto a collagen/fibronectin coated coverglass at the bottom of the well. After the cells had adhered, a type I collagen/fibronectin solution containing paramagnetic microbeads was overlaid onto the cells and allowed to polymerize. Cultures were either subjected to magnetic stimulation or grown outside the magnetic field. B) The magnet is rotated above the culture as cells start to invade up into the matrix. C) HT1080 cells seeded on a collagen-fibronectin coated coverslip and overlaid with a collagen/fibronectin matrix were cultured either in the presence or absence of a magnetic field. Percent invasion was calculated 24 and 48 hours following stimulation from three independent trials (15 fields were counted per culture). A difference in invasion (approx. 4–fold higher) between the stimulated cultures as compared to non-stimulated cultures was significant at 48 hours post-stimulation (P<0.005).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3040771&req=5

pone-0017277-g004: Upward Invasion Assay.A) HT1080 fibrosarcoma cells were seeded onto a collagen/fibronectin coated coverglass at the bottom of the well. After the cells had adhered, a type I collagen/fibronectin solution containing paramagnetic microbeads was overlaid onto the cells and allowed to polymerize. Cultures were either subjected to magnetic stimulation or grown outside the magnetic field. B) The magnet is rotated above the culture as cells start to invade up into the matrix. C) HT1080 cells seeded on a collagen-fibronectin coated coverslip and overlaid with a collagen/fibronectin matrix were cultured either in the presence or absence of a magnetic field. Percent invasion was calculated 24 and 48 hours following stimulation from three independent trials (15 fields were counted per culture). A difference in invasion (approx. 4–fold higher) between the stimulated cultures as compared to non-stimulated cultures was significant at 48 hours post-stimulation (P<0.005).
Mentions: The dimensionality of the environment is known to influence cellular behavior. Specifically, HT1080 cells have been shown to change their migration speed and persistence in three dimensions [37]. In our initial experiments, the cells are seeded on top of the matrix, invading from the top downward, thus beginning in two-dimensions and moving into three. To address the influence of dimensionality on mechanical invasion we changed the orientation of the stimulus so the cells would invade upwards. To do this, we first seeded the cells onto collagen/fibronectin-coated coverslips before overlaying and polymerizing the collagen/fibronectin/magnetic bead solution over them (Figure 4A). The magnetic field was then applied to the top of the culture by rotating the magnet above the stationary culture (Figure 4B). After 24 hours of stimulation, we found the cells invaded just as well as they did when they were seeded on top of the matrices prior to stimulation (6% invasion in non-stimulated and 13% in stimulated cultures) (Figure 4B). However, we found by 48 hours the difference between non-stimulated invasion and stimulated invasion was even larger such that 12% of the cells invaded in non-stimulated versus 41% invasion in the stimulated cultures. Thus, an even greater enhancement of invasion occurs in the response to applied mechanical stimulation when the cells began in a three-dimensional environment.

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