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Fluid shear stress regulates the invasive potential of glioma cells via modulation of migratory activity and matrix metalloproteinase expression.

Qazi H, Shi ZD, Tarbell JM - PLoS ONE (2011)

Bottom Line: This was confirmed by RT-PCR and with the aid of MMP-1 and MMP-2 shRNA constructs.The models developed for this study imply that flow-modulated motility involves mechanotransduction of fluid shear stress affecting MMP activation and expression.These models should be useful for the continued study of interstitial flow effects on processes that affect tumor progression.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, City College of New York, City University of New York, New York, New York, United States of America.

ABSTRACT

Background: Glioma cells are exposed to elevated interstitial fluid flow during the onset of angiogenesis, at the tumor periphery while invading normal parenchyma, within white matter tracts, and during vascular normalization therapy. Glioma cell lines that have been exposed to fluid flow forces in vivo have much lower invasive potentials than in vitro cell motility assays without flow would indicate.

Methodology/principal findings: A 3D Modified Boyden chamber (Darcy flow through collagen/cell suspension) model was designed to mimic the fluid dynamic microenvironment to study the effects of fluid shear stress on the migratory activity of glioma cells. Novel methods for gel compaction and isolation of chemotactic migration from flow stimulation were utilized for three glioma cell lines: U87, CNS-1, and U251. All physiologic levels of fluid shear stress suppressed the migratory activity of U87 and CNS-1 cell lines. U251 motility remained unaltered within the 3D interstitial flow model. Matrix Metalloproteinase (MMP) inhibition experiments and assays demonstrated that the glioma cells depended on MMP activity to invade, and suppression in motility correlated with downregulation of MMP-1 and MMP-2 levels. This was confirmed by RT-PCR and with the aid of MMP-1 and MMP-2 shRNA constructs.

Conclusions/significance: Fluid shear stress in the tumor microenvironment may explain reduced glioma invasion through modulation of cell motility and MMP levels. The flow-induced migration trends were consistent with reported invasive potentials of implanted gliomas. The models developed for this study imply that flow-modulated motility involves mechanotransduction of fluid shear stress affecting MMP activation and expression. These models should be useful for the continued study of interstitial flow effects on processes that affect tumor progression.

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Related in: MedlinePlus

Cell invasion without chemoattractant yielded diminished response of U87, CNS-1, and U251 cells after exposure to flow.All results were normalized to their respective controls (1.0). (A) Contrary to expectations of enhanced migration by flow-induced chemokine gradients, suppression of migration persisted in the U87 cell line and small but significant suppression was also observed in the U251 cells. Cells were exposed to a pressure drop of 7 cm H2O, 0.55 dynes/cm2 shear stress, and invasion assays were conducted without a chemoattractant. (B–D) TGF-α effectively directionalized migration of the glioma cell lines; suggests that it was necessary for the quantification of motility and invasive potentials of all the cell lines. Data presented as mean±SEM. Note: * p<0.05; ** p<0.005.
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pone-0020348-g004: Cell invasion without chemoattractant yielded diminished response of U87, CNS-1, and U251 cells after exposure to flow.All results were normalized to their respective controls (1.0). (A) Contrary to expectations of enhanced migration by flow-induced chemokine gradients, suppression of migration persisted in the U87 cell line and small but significant suppression was also observed in the U251 cells. Cells were exposed to a pressure drop of 7 cm H2O, 0.55 dynes/cm2 shear stress, and invasion assays were conducted without a chemoattractant. (B–D) TGF-α effectively directionalized migration of the glioma cell lines; suggests that it was necessary for the quantification of motility and invasive potentials of all the cell lines. Data presented as mean±SEM. Note: * p<0.05; ** p<0.005.

Mentions: Cell migration rates without the aid of TGF-α yielded diminished responses for the U87, CNS-1, and U251 cell lines after exposure to flow (Fig. 4A). It has been previously shown that flow-induced chemokine gradients can lead to increased cell migration [28]. In this study, however, there was no evidence of enhanced invasion by flow-induced chemokine gradients for any of the cell lines when compared to normalized controls. Though diminished, a 32% suppression of motility was still evident in the U87 cells exposed to 0.55 dynes/cm2 shear stress without migration to TGF-α, and though unexpected, there was a 21% suppression in migration of the U251 cells (p<0.05). There was no change in the CNS-1 migration rates. Furthermore, TGF-α effectively enhanced the U87, CNS-1, and U251 migratory activity by 89%, 566%, and 101% respectively when compared to normalized controls (p<0.005) (Fig. 4B–D).


Fluid shear stress regulates the invasive potential of glioma cells via modulation of migratory activity and matrix metalloproteinase expression.

Qazi H, Shi ZD, Tarbell JM - PLoS ONE (2011)

Cell invasion without chemoattractant yielded diminished response of U87, CNS-1, and U251 cells after exposure to flow.All results were normalized to their respective controls (1.0). (A) Contrary to expectations of enhanced migration by flow-induced chemokine gradients, suppression of migration persisted in the U87 cell line and small but significant suppression was also observed in the U251 cells. Cells were exposed to a pressure drop of 7 cm H2O, 0.55 dynes/cm2 shear stress, and invasion assays were conducted without a chemoattractant. (B–D) TGF-α effectively directionalized migration of the glioma cell lines; suggests that it was necessary for the quantification of motility and invasive potentials of all the cell lines. Data presented as mean±SEM. Note: * p<0.05; ** p<0.005.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102715&req=5

pone-0020348-g004: Cell invasion without chemoattractant yielded diminished response of U87, CNS-1, and U251 cells after exposure to flow.All results were normalized to their respective controls (1.0). (A) Contrary to expectations of enhanced migration by flow-induced chemokine gradients, suppression of migration persisted in the U87 cell line and small but significant suppression was also observed in the U251 cells. Cells were exposed to a pressure drop of 7 cm H2O, 0.55 dynes/cm2 shear stress, and invasion assays were conducted without a chemoattractant. (B–D) TGF-α effectively directionalized migration of the glioma cell lines; suggests that it was necessary for the quantification of motility and invasive potentials of all the cell lines. Data presented as mean±SEM. Note: * p<0.05; ** p<0.005.
Mentions: Cell migration rates without the aid of TGF-α yielded diminished responses for the U87, CNS-1, and U251 cell lines after exposure to flow (Fig. 4A). It has been previously shown that flow-induced chemokine gradients can lead to increased cell migration [28]. In this study, however, there was no evidence of enhanced invasion by flow-induced chemokine gradients for any of the cell lines when compared to normalized controls. Though diminished, a 32% suppression of motility was still evident in the U87 cells exposed to 0.55 dynes/cm2 shear stress without migration to TGF-α, and though unexpected, there was a 21% suppression in migration of the U251 cells (p<0.05). There was no change in the CNS-1 migration rates. Furthermore, TGF-α effectively enhanced the U87, CNS-1, and U251 migratory activity by 89%, 566%, and 101% respectively when compared to normalized controls (p<0.005) (Fig. 4B–D).

Bottom Line: This was confirmed by RT-PCR and with the aid of MMP-1 and MMP-2 shRNA constructs.The models developed for this study imply that flow-modulated motility involves mechanotransduction of fluid shear stress affecting MMP activation and expression.These models should be useful for the continued study of interstitial flow effects on processes that affect tumor progression.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, City College of New York, City University of New York, New York, New York, United States of America.

ABSTRACT

Background: Glioma cells are exposed to elevated interstitial fluid flow during the onset of angiogenesis, at the tumor periphery while invading normal parenchyma, within white matter tracts, and during vascular normalization therapy. Glioma cell lines that have been exposed to fluid flow forces in vivo have much lower invasive potentials than in vitro cell motility assays without flow would indicate.

Methodology/principal findings: A 3D Modified Boyden chamber (Darcy flow through collagen/cell suspension) model was designed to mimic the fluid dynamic microenvironment to study the effects of fluid shear stress on the migratory activity of glioma cells. Novel methods for gel compaction and isolation of chemotactic migration from flow stimulation were utilized for three glioma cell lines: U87, CNS-1, and U251. All physiologic levels of fluid shear stress suppressed the migratory activity of U87 and CNS-1 cell lines. U251 motility remained unaltered within the 3D interstitial flow model. Matrix Metalloproteinase (MMP) inhibition experiments and assays demonstrated that the glioma cells depended on MMP activity to invade, and suppression in motility correlated with downregulation of MMP-1 and MMP-2 levels. This was confirmed by RT-PCR and with the aid of MMP-1 and MMP-2 shRNA constructs.

Conclusions/significance: Fluid shear stress in the tumor microenvironment may explain reduced glioma invasion through modulation of cell motility and MMP levels. The flow-induced migration trends were consistent with reported invasive potentials of implanted gliomas. The models developed for this study imply that flow-modulated motility involves mechanotransduction of fluid shear stress affecting MMP activation and expression. These models should be useful for the continued study of interstitial flow effects on processes that affect tumor progression.

Show MeSH
Related in: MedlinePlus