Displacement fields using correlation methods as a tool to investigate cell migration in 3D collagen gels

Growth factor–induced migration is a critical step in the dissemination and metastasis of solid tumors. Although differences in properties characterizing cell migration on two-dimensional (2D) substrata versus within three-dimensional (3D) matrices have been noted for particular growth factor stimuli, the 2D approach remains in more common use as an efficient surrogate, especially for high-throughput experiments. We therefore were motivated to investigate which migration properties measured in various 2D assays might be reflective of 3D migratory behavioral responses. We used human triple-negative breast cancer lines stimulated by a panel of receptor tyrosine kinase ligands relevant to mammary carcinoma progression. Whereas 2D migration properties did not correlate well with 3D behavior across multiple growth factors, we found that increased membrane protrusion elicited by growth factor stimulation did relate robustly to enhanced 3D migration properties of the MDA-MB-231 and MDA-MB-157 lines. Interestingly, we observed this to be a more reliable relationship than cognate receptor expression or activation levels across these and two additional mammary tumor lines.

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Matrix metalloproteinase-9 activates TGF-β and stimulates fibroblast contraction of collagen gels

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00015.2014 ◽

2014 ◽

Vol 306 (11) ◽

pp. L1006-L1015 ◽

Cited By ~ 73

Author(s):

Tetsu Kobayashi ◽

HuiJung Kim ◽

Xiangde Liu ◽

Hisatoshi Sugiura ◽

Tadashi Kohyama ◽

...

Keyword(s):

Matrix Metalloproteinase ◽

Human Fibroblasts ◽

Matrix Metalloproteinase 9 ◽

Lung Fibroblasts ◽

Type I ◽

Image Analysis System ◽

Collagen Gels ◽

3D Collagen ◽

Metalloproteinase 9 ◽

Tgf Β1

Matrix metalloproteinase-9 (MMP-9) is a matrix-degrading enzyme implicated in many biological processes, including inflammation. It is produced by many cells, including fibroblasts. When cultured in three-dimensional (3D) collagen gels, fibroblasts contract the surrounding matrix, a function that is thought to model the contraction that characterizes both normal wound repair and fibrosis. The current study was designed to evaluate the role of endogenously produced MMP-9 in fibroblast contraction of 3D collagen gels. Fibroblasts from mice lacking expression of MMP-9 and human lung fibroblasts (HFL-1) transfected with MMP-9 small-interfering RNA (siRNA) were used. Fibroblasts were cast into type I collagen gels and floated in culture medium with or without transforming growth factor (TGF)-β1 for 5 days. Gel size was determined daily using an image analysis system. Gels made from MMP-9 siRNA-treated human fibroblasts contracted less than control fibroblasts, as did fibroblasts incubated with a nonspecific MMP inhibitor. Similarly, fibroblasts cultured from MMP-9-deficient mice contracted gels less than did fibroblasts from control mice. Transfection of the MMP-9-deficient murine fibroblasts with a vector expressing murine MMP-9 restored contractile activity to MMP-9-deficient fibroblasts. Inhibition of MMP-9 reduced active TGF-β1 and reduced several TGF-β1-driven responses, including activity of a Smad3 reporter gene and production of fibronectin. Because TGF-β1 also drives fibroblast gel contraction, this suggests the mechanism for MMP-9 regulation of contraction is through the generation of active TGF-β1. This study provides direct evidence that endogenously produced MMP-9 has a role in regulation of tissue contraction of 3D collagen gels mediated by fibroblasts.

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The Effects of Geometry and Static Boundary Conditions on Microvessel Outgrowth in a 3D Model of Angiogenesis

ASME 2010 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2010-19587 ◽

2010 ◽

Cited By ~ 1

Author(s):

Clayton J. Underwood ◽

Laxminarayanan Krishnan ◽

Lowell T. Edgar ◽

Steve Maas ◽

James B. Hoying ◽

...

Keyword(s):

Boundary Condition ◽

Boundary Conditions ◽

Direct Relationship ◽

3D Model ◽

Mechanical Strain ◽

Matrix Stiffness ◽

Collagen Gels ◽

3D Collagen ◽

In Vitro Angiogenesis

We reported previously that, in addition to mechanical strain, a constrained boundary condition alone can alter the organization of microvessel outgrowth during in vitro angiogenesis [1]. After 6 days of culture in vitro, microvessels aligned parallel to the long axis of rectangular 3D collagen gels that had constrained edges on the ends. However, unconstrained cultures did not show any alignment of microvessels. The ability to direct microvessel outgrowth during angiogenesis has significant implications for engineering prevascularized grafts and tissues in vitro, therefore an understanding of this process is important. Since there is direct relationship between the ability of endothelial cells to contract 3D gels and matrix stiffness [2], we hypothesize that some constrained boundary conditions will increase the apparent matrix stiffness and in turn will limit gel contraction, prevent microvessel alignment, and reduce microvessel outgrowth. The objective of this study was to compare microvessel growth and alignment under several different static boundary conditions.

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