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Pogoda K, Bucki R, Byfield FJ, Cruz K, Lee T, Marcinkiewicz C, Janmey PA. Soft Substrates Containing Hyaluronan Mimic the Effects of Increased Stiffness on Morphology, Motility, and Proliferation of Glioma Cells. Biomacromolecules 2017; 18:3040-3051. [PMID: 28858529 DOI: 10.1021/acs.biomac.7b00324] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Unlike many other cancer cells that grow in tumors characterized by an abnormally stiff collagen-enriched stroma, glioma cells proliferate and migrate in the much softer environment of the brain, which generally lacks the filamentous protein matrix characteristic of breast, liver, colorectal, and other types of cancer. Glial cell-derived tumors and the cells derived from them are highly heterogeneous and variable in their mechanical properties, their response to treatments, and their properties in vitro. Some glioma samples are stiffer than normal brain when measured ex vivo, but even those that are soft in vitro stiffen after deformation by pressure gradients that arise in the tumor environment in vivo. Such mechanical differences can strongly alter the phenotype of cultured glioma cells. Alternatively, chemical signaling might elicit the same phenotype as increased stiffness by activating intracellular messengers common to both initial stimuli. In this study the responses of three different human glioma cell lines to changes in substrate stiffness are compared with their responses on very soft substrates composed of a combination of hyaluronic acid and a specific integrin ligand, either laminin or collagen I. By quantifying cell morphology, stiffness, motility, proliferation, and secretion of the cytokine IL-8, glioma cell responses to increased stiffness are shown to be nearly identically elicited by substrates containing hyaluronic acid, even in the absence of increased stiffness. PI3-kinase activity was required for the response to hyaluronan but not to stiffness. This outcome suggests that hyaluronic acid can trigger the same cellular response, as can be obtained by mechanical force transduced from a stiff environment, and demonstrates that chemical and mechanical features of the tumor microenvironment can achieve equivalent reactions in cancer cells.
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Affiliation(s)
- Katarzyna Pogoda
- Institute for Medicine and Engineering, University of Pennsylvania , 3340 Smith Walk, Philadelphia, Pennsylvania 19104, United States.,Institute of Nuclear Physics Polish Academy of Sciences , PL-31342 Krakow, Poland
| | - Robert Bucki
- Institute for Medicine and Engineering, University of Pennsylvania , 3340 Smith Walk, Philadelphia, Pennsylvania 19104, United States.,Department of Microbiological and Nanobiomedical Engineering, Medical University of Bialystok , 15-222 Bialystok, Poland
| | - Fitzroy J Byfield
- Institute for Medicine and Engineering, University of Pennsylvania , 3340 Smith Walk, Philadelphia, Pennsylvania 19104, United States
| | - Katrina Cruz
- Institute for Medicine and Engineering, University of Pennsylvania , 3340 Smith Walk, Philadelphia, Pennsylvania 19104, United States
| | - Tongkeun Lee
- Institute for Medicine and Engineering, University of Pennsylvania , 3340 Smith Walk, Philadelphia, Pennsylvania 19104, United States
| | - Cezary Marcinkiewicz
- CoE Department of Bioengineering, Temple University , Philadelphia, Pennsylvania 19122, United States
| | - Paul A Janmey
- Institute for Medicine and Engineering, University of Pennsylvania , 3340 Smith Walk, Philadelphia, Pennsylvania 19104, United States.,Department of Physiology, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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102
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Sivakumar H, Strowd R, Skardal A. Exploration of Dynamic Elastic Modulus Changes on Glioblastoma Cell Populations with Aberrant EGFR Expression as a Potential Therapeutic Intervention Using a Tunable Hyaluronic Acid Hydrogel Platform. Gels 2017; 3:gels3030028. [PMID: 30920523 PMCID: PMC6318698 DOI: 10.3390/gels3030028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/21/2017] [Accepted: 07/07/2017] [Indexed: 01/07/2023] Open
Abstract
Glioblastoma (GBM) is one of most aggressive forms of brain cancer, with a median survival time of 14.6 months following diagnosis. This low survival rate could in part be attributed to the lack of model systems of this type of cancer that faithfully recapitulate the tumor architecture and microenvironment seen in vivo in humans. Therapeutic studies would provide results that could be translated to the clinic efficiently. Here, we assess the role of the tumor microenvironment physical parameters on the tumor, and its potential use as a biomarker using a hyaluronic acid hydrogel system capable of elastic modulus tuning and dynamic elastic moduli changes. Experiments were conducted to assess the sensitivity of glioblastoma cell populations with different mutations to varying elastic moduli. Cells with aberrant epithelial growth factor receptor (EGFR) expression have a predilection for a stiffer environment, sensing these parameters through focal adhesion kinase (FAK). Importantly, the inhibition of FAK or EGFR generally resulted in reversed elastic modulus preference. Lastly, we explore the concept of therapeutically targeting the elastic modulus and dynamically reducing it via chemical or enzymatic degradation, both showing the capability to reduce or stunt proliferation rates of these GBM populations.
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Affiliation(s)
- Hemamylammal Sivakumar
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
| | - Roy Strowd
- Department of Neurology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
- Comprehensive Cancer Center at Wake Forest Baptist, Wake Forest Baptist Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
| | - Aleksander Skardal
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
- Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
- Department of Cancer Biology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
- Comprehensive Cancer Center at Wake Forest Baptist, Wake Forest Baptist Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
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103
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Abstract
Neurons allocated to sense organs respond rapidly to mechanical signals dictating behavioral responses at the organism level. The receptors that transduce these signals, and underlie these senses, are mechanically gated channels. Research on mechanosensation over the past decade, employing in many cases Drosophila as a model, has focused in typifying these receptors and in exploring the different ways, depending on context, in which these mechanosensors are modulated. In this review, we discuss first what we have learned from Drosophila on these mechanisms and we describe the different mechanosensory organs present in the Drosophila larvae and adult. Secondly, we focus on the progress obtained by studying the fly on the characterization of the mechanosensory crosstalk underlying complex behaviors like motor coordination. Finally, turning to a cellular level, we summarize what is known on the mechanical properties and sensing capabilities of neural cells and how they may affect neural physiology and pathology.
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Affiliation(s)
- Katerina Karkali
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Cientific de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Enrique Martin-Blanco
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Cientific de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain.
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104
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Alibert C, Goud B, Manneville JB. Are cancer cells really softer than normal cells? Biol Cell 2017; 109:167-189. [DOI: 10.1111/boc.201600078] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 02/23/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Charlotte Alibert
- Institut Curie; PSL Research University, CNRS; UMR 144 Paris France
- Sorbonne Universités, UPMC University Paris 06, CNRS; UMR 144 Paris France
| | - Bruno Goud
- Institut Curie; PSL Research University, CNRS; UMR 144 Paris France
- Sorbonne Universités, UPMC University Paris 06, CNRS; UMR 144 Paris France
| | - Jean-Baptiste Manneville
- Institut Curie; PSL Research University, CNRS; UMR 144 Paris France
- Sorbonne Universités, UPMC University Paris 06, CNRS; UMR 144 Paris France
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105
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Integrating the glioblastoma microenvironment into engineered experimental models. Future Sci OA 2017; 3:FSO189. [PMID: 28883992 PMCID: PMC5583655 DOI: 10.4155/fsoa-2016-0094] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 02/22/2017] [Indexed: 12/13/2022] Open
Abstract
Glioblastoma (GBM) is the most lethal cancer originating in the brain. Its high mortality rate has been attributed to therapeutic resistance and rapid, diffuse invasion - both of which are strongly influenced by the unique microenvironment. Thus, there is a need to develop new models that mimic individual microenvironmental features and are able to provide clinically relevant data. Current understanding of the effects of the microenvironment on GBM progression, established experimental models of GBM and recent developments using bioengineered microenvironments as ex vivo experimental platforms that mimic the biochemical and physical properties of GBM tumors are discussed.
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106
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Koivisto JT, Joki T, Parraga JE, Pääkkönen R, Ylä-Outinen L, Salonen L, Jönkkäri I, Peltola M, Ihalainen TO, Narkilahti S, Kellomäki M. Bioamine-crosslinked gellan gum hydrogel for neural tissue engineering. Biomed Mater 2017; 12:025014. [DOI: 10.1088/1748-605x/aa62b0] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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107
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Budday S, Sommer G, Birkl C, Langkammer C, Haybaeck J, Kohnert J, Bauer M, Paulsen F, Steinmann P, Kuhl E, Holzapfel GA. Mechanical characterization of human brain tissue. Acta Biomater 2017; 48:319-340. [PMID: 27989920 DOI: 10.1016/j.actbio.2016.10.036] [Citation(s) in RCA: 283] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 12/13/2022]
Abstract
Mechanics are increasingly recognized to play an important role in modulating brain form and function. Computational simulations are a powerful tool to predict the mechanical behavior of the human brain in health and disease. The success of these simulations depends critically on the underlying constitutive model and on the reliable identification of its material parameters. Thus, there is an urgent need to thoroughly characterize the mechanical behavior of brain tissue and to identify mathematical models that capture the tissue response under arbitrary loading conditions. However, most constitutive models have only been calibrated for a single loading mode. Here, we perform a sequence of multiple loading modes on the same human brain specimen - simple shear in two orthogonal directions, compression, and tension - and characterize the loading-mode specific regional and directional behavior. We complement these three individual tests by combined multiaxial compression/tension-shear tests and discuss effects of conditioning and hysteresis. To explore to which extent the macrostructural response is a result of the underlying microstructural architecture, we supplement our biomechanical tests with diffusion tensor imaging and histology. We show that the heterogeneous microstructure leads to a regional but not directional dependence of the mechanical properties. Our experiments confirm that human brain tissue is nonlinear and viscoelastic, with a pronounced compression-tension asymmetry. Using our measurements, we compare the performance of five common constitutive models, neo-Hookean, Mooney-Rivlin, Demiray, Gent, and Ogden, and show that only the isotropic modified one-term Ogden model is capable of representing the hyperelastic behavior under combined shear, compression, and tension loadings: with a shear modulus of 0.4-1.4kPa and a negative nonlinearity parameter it captures the compression-tension asymmetry and the increase in shear stress under superimposed compression but not tension. Our results demonstrate that material parameters identified for a single loading mode fail to predict the response under arbitrary loading conditions. Our systematic characterization of human brain tissue will lead to more accurate computational simulations, which will allow us to determine criteria for injury, to develop smart protection systems, and to predict brain development and disease progression. STATEMENT OF SIGNIFICANCE There is a pressing need to characterize the mechanical behavior of human brain tissue under multiple loading conditions, and to identify constitutive models that are able to capture the tissue response under these conditions. We perform a sequence of experimental tests on the same brain specimen to characterize the regional and directional behavior, and we supplement our tests with DTI and histology to explore to which extent the macrostructural response is a result of the underlying microstructure. Results demonstrate that human brain tissue is nonlinear and viscoelastic, with a pronounced compression-tension asymmetry, and we show that the multiaxial data can best be captured by a modified version of the one-term Ogden model.
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Affiliation(s)
- S Budday
- Department of Mechanical Engineering, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - G Sommer
- Institute of Biomechanics, Graz University of Technology, 8010 Graz, Austria
| | - C Birkl
- Department of Neurology, Medical University of Graz, 8036 Graz, Austria
| | - C Langkammer
- Department of Neurology, Medical University of Graz, 8036 Graz, Austria
| | - J Haybaeck
- Department of Neuropathology, Institute of Pathology, Medical University of Graz, 8036 Graz, Austria
| | - J Kohnert
- Department of Mechanical Engineering, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - M Bauer
- Department of Mechanical Engineering, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - F Paulsen
- Chair of Anatomy II, University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - P Steinmann
- Department of Mechanical Engineering, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - E Kuhl
- Departments of Mechanical Engineering & Bioengineering, Stanford University, CA 94305, USA
| | - G A Holzapfel
- Institute of Biomechanics, Graz University of Technology, 8010 Graz, Austria; Norwegian University of Science and Technology (NTNU), Faculty of Engineering Science and Technology, 7491 Trondheim, Norway.
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108
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Mechanosensing is critical for axon growth in the developing brain. Nat Neurosci 2016; 19:1592-1598. [PMID: 27643431 PMCID: PMC5531257 DOI: 10.1038/nn.4394] [Citation(s) in RCA: 379] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/25/2016] [Indexed: 02/07/2023]
Abstract
During nervous system development, neurons extend axons along well-defined pathways. The current understanding of axon pathfinding is based mainly on chemical signaling. However, growing neurons interact not only chemically but also mechanically with their environment. Here we identify mechanical signals as important regulators of axon pathfinding. In vitro, substrate stiffness determined growth patterns of Xenopus retinal ganglion cell axons. In vivo atomic force microscopy revealed a noticeable pattern of stiffness gradients in the embryonic brain. Retinal ganglion cell axons grew toward softer tissue, which was reproduced in vitro in the absence of chemical gradients. To test the importance of mechanical signals for axon growth in vivo, we altered brain stiffness, blocked mechanotransduction pharmacologically and knocked down the mechanosensitive ion channel piezo1. All treatments resulted in aberrant axonal growth and pathfinding errors, suggesting that local tissue stiffness, read out by mechanosensitive ion channels, is critically involved in instructing neuronal growth in vivo.
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109
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Canovic EP, Qing B, Mijailovic AS, Jagielska A, Whitfield MJ, Kelly E, Turner D, Sahin M, Van Vliet KJ. Characterizing Multiscale Mechanical Properties of Brain Tissue Using Atomic Force Microscopy, Impact Indentation, and Rheometry. J Vis Exp 2016. [PMID: 27684097 DOI: 10.3791/54201] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
To design and engineer materials inspired by the properties of the brain, whether for mechanical simulants or for tissue regeneration studies, the brain tissue itself must be well characterized at various length and time scales. Like many biological tissues, brain tissue exhibits a complex, hierarchical structure. However, in contrast to most other tissues, brain is of very low mechanical stiffness, with Young's elastic moduli E on the order of 100s of Pa. This low stiffness can present challenges to experimental characterization of key mechanical properties. Here, we demonstrate several mechanical characterization techniques that have been adapted to measure the elastic and viscoelastic properties of hydrated, compliant biological materials such as brain tissue, at different length scales and loading rates. At the microscale, we conduct creep-compliance and force relaxation experiments using atomic force microscope-enabled indentation. At the mesoscale, we perform impact indentation experiments using a pendulum-based instrumented indenter. At the macroscale, we conduct parallel plate rheometry to quantify the frequency dependent shear elastic moduli. We also discuss the challenges and limitations associated with each method. Together these techniques enable an in-depth mechanical characterization of brain tissue that can be used to better understand the structure of brain and to engineer bio-inspired materials.
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Affiliation(s)
| | - Bo Qing
- Department of Biological Engineering, Massachusetts Institute of Technology
| | | | - Anna Jagielska
- Department of Biological Engineering, Massachusetts Institute of Technology
| | | | - Elyza Kelly
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School
| | - Daria Turner
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School
| | - Mustafa Sahin
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School
| | - Krystyn J Van Vliet
- Department of Materials Science and Engineering, Massachusetts Institute of Technology; Department of Biological Engineering, Massachusetts Institute of Technology;
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110
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Feng Y, Clayton EH, Okamoto RJ, Engelbach J, Bayly PV, Garbow JR. A longitudinal magnetic resonance elastography study of murine brain tumors following radiation therapy. Phys Med Biol 2016; 61:6121-31. [PMID: 27461395 DOI: 10.1088/0031-9155/61/16/6121] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
An accurate and noninvasive method for assessing treatment response following radiotherapy is needed for both treatment monitoring and planning. Measurement of solid tumor volume alone is not sufficient for reliable early detection of therapeutic response, since changes in physiological and/or biomechanical properties can precede tumor volume change following therapy. In this study, we use magnetic resonance elastography to evaluate the treatment effect after radiotherapy in a murine brain tumor model. Shear modulus was calculated and compared between the delineated tumor region of interest (ROI) and its contralateral, mirrored counterpart. We also compared the shear modulus from both the irradiated and non-irradiated tumor and mirror ROIs longitudinally, sampling four time points spanning 9-19 d post tumor implant. Results showed that the tumor ROI had a lower shear modulus than that of the mirror ROI, independent of radiation. The shear modulus of the tumor ROI decreased over time for both the treated and untreated groups. By contrast, the shear modulus of the mirror ROI appeared to be relatively constant for the treated group, while an increasing trend was observed for the untreated group. The results provide insights into the tumor properties after radiation treatment and demonstrate the potential of using the mechanical properties of the tumor as a biomarker. In future studies, more closely spaced time points will be employed for detailed analysis of the radiation effect.
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Affiliation(s)
- Y Feng
- School of Mechanical and Electronic Engineering, Soochow University, Suzhou, Jiangsu, People's Republic of China. Robotics and Microsystems Center, Soochow University, Suzhou, Jiangsu, People's Republic of China. School of Computer Science and Engineering, Soochow University, Suzhou, Jiangsu, People's Republic of China
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111
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Vahabi M, Sharma A, Licup AJ, van Oosten ASG, Galie PA, Janmey PA, MacKintosh FC. Elasticity of fibrous networks under uniaxial prestress. SOFT MATTER 2016; 12:5050-60. [PMID: 27174568 DOI: 10.1039/c6sm00606j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We present theoretical and experimental studies of the elastic response of fibrous networks subjected to uniaxial strain. Uniaxial compression or extension is applied to extracellular networks of fibrin and collagen using a shear rheometer with free water in/outflow. Both uniaxial stress and the network shear modulus are measured. Prior work [van Oosten, et al., Sci. Rep., 2015, 6, 19270] has shown softening/stiffening of these networks under compression/extension, together with a nonlinear response to shear, but the origin of such behaviour remains poorly understood. Here, we study how uniaxial strain influences the nonlinear mechanics of fibrous networks. Using a computational network model with bendable and stretchable fibres, we show that the softening/stiffening behaviour can be understood for fixed lateral boundaries in 2D and 3D networks with comparable average connectivities to the experimental extracellular networks. Moreover, we show that the onset of stiffening depends strongly on the imposed uniaxial strain. Our study highlights the importance of both uniaxial strain and boundary conditions in determining the mechanical response of hydrogels.
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Affiliation(s)
- Mahsa Vahabi
- Department of Physics and Astronomy, VU University, Amsterdam, The Netherlands.
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112
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Differential response of patient-derived primary glioblastoma cells to environmental stiffness. Sci Rep 2016; 6:23353. [PMID: 26996336 PMCID: PMC4800394 DOI: 10.1038/srep23353] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 03/04/2016] [Indexed: 02/06/2023] Open
Abstract
The ability of cancer cells to sense external mechanical forces has emerged as a significant factor in the promotion of cancer invasion. Currently there are conflicting reports in the literature with regard to whether glioblastoma (GBM) brain cancer cell migration and invasion is rigidity-sensitive. In order to address this question we have compared the rigidity-response of primary patient-derived GBM lines. Cells were plated on polyacrylamide gels of defined rigidity that reflect the diversity of the brain tissue mechanical environment, and cell morphology and migration were analysed by time-lapse microscopy. Invasiveness was assessed in multicellular spheroids embedded in 3D matrigel cultures. Our data reveal a range of rigidity-dependent responses between the patient-derived cell lines, from reduced migration on the most compliant tissue stiffness to those that are insensitive to substrate rigidity and are equally migratory irrespective of the underlying substrate stiffness. Notably, the rigidity-insensitive GBM cells show the greatest invasive capacity in soft 3D matrigel cultures. Collectively our data confirm both rigidity-dependent and independent behaviour in primary GBM patient-derived cells.
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113
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Zhao C, Ban N, Dai S, Zhang X, Zhang L, Xu P, Chen W, Sun J, Bao Z, Chang H, Wang D, Ren J. The role of Alix in the proliferation of human glioma cells. Hum Pathol 2016; 52:110-8. [PMID: 26980041 DOI: 10.1016/j.humpath.2015.09.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Revised: 08/31/2015] [Accepted: 09/10/2015] [Indexed: 12/15/2022]
Abstract
Apoptosis-linked-gene-2-interacting protein 1 (Alix) is involved in the endosome-lysosome system in the cytoplasm. The normal function of Alix may be altered by ALG-2 toward a destructive role during active cell death. Alix also may play a role in regulation of cell proliferation. However, the role of Alix in human glioma has not been elucidated yet. This study intended to clarify the relationship between Alix and glioma pathologic grades and its role in the proliferation of glioma cells. Our findings showed that Alix protein concentrations were significantly elevated in high-grade glioma tissue compared with low-grade glioma (P < .0001). Immunohistochemical study revealed that Alix was overexpressed in 75 resected glioma tissues and may forecast poor survival. Alix expression was increased in resting serum-stimulated glioma cells. Additionally, we reduced Alix expression in U251MG cells and then found that cell viability was decreased significantly when p21 expression increased. Colony formation assay and flow cytometry analysis demonstrated that reduced Alix expression may lead to growth inhibition and cell cycle arrest. In summary, our findings suggest that Alix plays an important role in the proliferation of glioma cells and may be a novel therapeutic target.
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Affiliation(s)
- Chengjin Zhao
- Department of Neurosurgery, Affiliated Second Peoples Hospital of NanTong, Nantong University, Nantong, 226002, Jiangsu Province, People's Republic of China
| | - Na Ban
- Department of Pathology, Medical College and Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, Nantong, 226001
| | - Shirong Dai
- Department of Neurosurgery, Affiliated Second Peoples Hospital of NanTong, Nantong University, Nantong, 226002, Jiangsu Province, People's Republic of China
| | - Xiubing Zhang
- Department of Neurosurgery, Affiliated Second Peoples Hospital of NanTong, Nantong University, Nantong, 226002, Jiangsu Province, People's Republic of China
| | - Li Zhang
- Department of Pathology, Medical College and Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, Nantong, 226001
| | - Peng Xu
- Department of Pathology, Medical College and Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, Nantong, 226001
| | - Wenjuan Chen
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, Nantong, 226001
| | - Jie Sun
- Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, Nantong, 226001
| | - Zhen Bao
- The First Affiliated Hospital of Soochow University, Suzhou, 215006, Jiangsu Province
| | - Hao Chang
- Department of Neurosurgery, Wuxi Second People's Hospital of Nanjing Medical University, Wuxi, 214002, China
| | - Donglin Wang
- Department of Pathology, Medical College and Jiangsu Province Key Laboratory for Inflammation and Molecular Drug Target, Nantong University, Nantong, 226001
| | - Jianbing Ren
- Department of Neurosurgery, Affiliated Second Peoples Hospital of NanTong, Nantong University, Nantong, 226002, Jiangsu Province, People's Republic of China.
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114
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Abstract
Currently, biomechanics of living cells is in the focus of interest due to noticeable capability of such techniques like atomic force microscopy (AFM) to probe cellular properties at the single cell level directly on living cells. The research carried out, so far, delivered data showing, on the one hand, the use of cellular mechanics as a biomarker of various pathological changes, which, on the other hand, reveal relative nature of biomechanics. In the AFM, the elastic properties of living cells are delivered from indentation experiments and described quantitatively by Young's modulus defined here as a measure of cellular deformability. Here, the AFM studies directly comparing the mechanical properties of normal and cancerous cells are summarized and presented together with a few important issues related to the relativeness of Young's modulus.
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Affiliation(s)
- Małgorzata Lekka
- Institute of Nuclear Physics, PAS, Radzikowskiego 152, 31-342 Kraków, Poland
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115
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Normal and Fibrotic Rat Livers Demonstrate Shear Strain Softening and Compression Stiffening: A Model for Soft Tissue Mechanics. PLoS One 2016; 11:e0146588. [PMID: 26735954 PMCID: PMC4703410 DOI: 10.1371/journal.pone.0146588] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/18/2015] [Indexed: 12/19/2022] Open
Abstract
Tissues including liver stiffen and acquire more extracellular matrix with fibrosis. The relationship between matrix content and stiffness, however, is non-linear, and stiffness is only one component of tissue mechanics. The mechanical response of tissues such as liver to physiological stresses is not well described, and models of tissue mechanics are limited. To better understand the mechanics of the normal and fibrotic rat liver, we carried out a series of studies using parallel plate rheometry, measuring the response to compressive, extensional, and shear strains. We found that the shear storage and loss moduli G’ and G” and the apparent Young's moduli measured by uniaxial strain orthogonal to the shear direction increased markedly with both progressive fibrosis and increasing compression, that livers shear strain softened, and that significant increases in shear modulus with compressional stress occurred within a range consistent with increased sinusoidal pressures in liver disease. Proteoglycan content and integrin-matrix interactions were significant determinants of liver mechanics, particularly in compression. We propose a new non-linear constitutive model of the liver. A key feature of this model is that, while it assumes overall liver incompressibility, it takes into account water flow and solid phase compressibility. In sum, we report a detailed study of non-linear liver mechanics under physiological strains in the normal state, early fibrosis, and late fibrosis. We propose a constitutive model that captures compression stiffening, tension softening, and shear softening, and can be understood in terms of the cellular and matrix components of the liver.
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116
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Ridge KM, Shumaker D, Robert A, Hookway C, Gelfand VI, Janmey PA, Lowery J, Guo M, Weitz DA, Kuczmarski E, Goldman RD. Methods for Determining the Cellular Functions of Vimentin Intermediate Filaments. Methods Enzymol 2015; 568:389-426. [PMID: 26795478 DOI: 10.1016/bs.mie.2015.09.036] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The type III intermediate filament protein vimentin was once thought to function mainly as a static structural protein in the cytoskeleton of cells of mesenchymal origin. Now, however, vimentin is known to form a dynamic, flexible network that plays an important role in a number of signaling pathways. Here, we describe various methods that have been developed to investigate the cellular functions of the vimentin protein and intermediate filament network, including chemical disruption, photoactivation and photoconversion, biolayer interferometry, soluble bead binding assay, three-dimensional substrate experiments, collagen gel contraction, optical-tweezer active microrheology, and force spectrum microscopy. Using these techniques, the contributions of vimentin to essential cellular processes can be probed in ever further detail.
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Affiliation(s)
- Karen M Ridge
- Division of Pulmonary and Critical Care Medicine, Chicago, Illinois, USA; Department of Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA; Veterans Administration, Chicago, Illinois, USA.
| | - Dale Shumaker
- Division of Pulmonary and Critical Care Medicine, Chicago, Illinois, USA; Department of Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Amélie Robert
- Department of Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Caroline Hookway
- Department of Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Vladimir I Gelfand
- Department of Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Paul A Janmey
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Departments of Physiology and Physics & Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jason Lowery
- Division of Pulmonary and Critical Care Medicine, Chicago, Illinois, USA
| | - Ming Guo
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
| | - David A Weitz
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA; Department of Physics, Harvard University, Cambridge, Massachusetts, USA
| | - Edward Kuczmarski
- Department of Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Robert D Goldman
- Division of Pulmonary and Critical Care Medicine, Chicago, Illinois, USA; Department of Cell and Molecular Biology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
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117
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Mihai LA, Chin L, Janmey PA, Goriely A. A comparison of hyperelastic constitutive models applicable to brain and fat tissues. J R Soc Interface 2015; 12:0486. [PMID: 26354826 PMCID: PMC4614457 DOI: 10.1098/rsif.2015.0486] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 08/20/2015] [Indexed: 12/26/2022] Open
Abstract
In some soft biological structures such as brain and fat tissues, strong experimental evidence suggests that the shear modulus increases significantly under increasing compressive strain, but not under tensile strain, whereas the apparent Young's elastic modulus increases or remains almost constant when compressive strain increases. These tissues also exhibit a predominantly isotropic, incompressible behaviour. Our aim is to capture these seemingly contradictory mechanical behaviours, both qualitatively and quantitatively, within the framework of finite elasticity, by modelling a soft tissue as a homogeneous, isotropic, incompressible, hyperelastic material and comparing our results with available experimental data. Our analysis reveals that the Fung and Gent models, which are typically used to model soft tissues, are inadequate for the modelling of brain or fat under combined stretch and shear, and so are the classical neo-Hookean and Mooney-Rivlin models used for elastomers. However, a subclass of Ogden hyperelastic models are found to be in excellent agreement with the experiments. Our findings provide explicit models suitable for integration in large-scale finite-element computations.
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Affiliation(s)
- L Angela Mihai
- School of Mathematics, Cardiff University, Senghennydd Road, Cardiff CF24 4AG, UK
| | - LiKang Chin
- Institute for Medicine and Engineering, University of Pennsylvania, 3340 Smith Walk, Philadelphia, PA, USA
| | - Paul A Janmey
- Departments of Physiology and Physics and Astronomy, Institute for Medicine and Engineering, University of Pennsylvania, 3340 Smith Walk, Philadelphia, PA, USA
| | - Alain Goriely
- Mathematical Institute, University of Oxford, Woodstock Road, Oxford OX2 6GG, UK
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118
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Xu X, Safran SA. Nonlinearities of biopolymer gels increase the range of force transmission. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:032728. [PMID: 26465519 DOI: 10.1103/physreve.92.032728] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Indexed: 06/05/2023]
Abstract
We present a model of biopolymer gels that includes two types of elastic nonlinearities, stiffening under extension and softening (due to buckling) under compression, to predict the elastic anisotropy induced by both external as well as internal (e.g., due to cell contractility) stresses in biopolymer gels. We show how the stretch-induced anisotropy and the strain-stiffening nonlinearity increase both the amplitude and power-law range of transmission of internal, contractile, cellular forces, and relate this to recent experiments.
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Affiliation(s)
- Xinpeng Xu
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Samuel A Safran
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
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119
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Kim Y, Powathil G, Kang H, Trucu D, Kim H, Lawler S, Chaplain M. Strategies of eradicating glioma cells: a multi-scale mathematical model with MiR-451-AMPK-mTOR control. PLoS One 2015; 10:e0114370. [PMID: 25629604 PMCID: PMC4309536 DOI: 10.1371/journal.pone.0114370] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 11/06/2014] [Indexed: 01/06/2023] Open
Abstract
The cellular dispersion and therapeutic control of glioblastoma, the most aggressive type of primary brain cancer, depends critically on the migration patterns after surgery and intracellular responses of the individual cancer cells in response to external biochemical and biomechanical cues in the microenvironment. Recent studies have shown that a particular microRNA, miR-451, regulates downstream molecules including AMPK and mTOR to determine the balance between rapid proliferation and invasion in response to metabolic stress in the harsh tumor microenvironment. Surgical removal of main tumor is inevitably followed by recurrence of the tumor due to inaccessibility of dispersed tumor cells in normal brain tissue. In order to address this multi-scale nature of glioblastoma proliferation and invasion and its response to conventional treatment, we propose a hybrid model of glioblastoma that analyses spatio-temporal dynamics at the cellular level, linking individual tumor cells with the macroscopic behaviour of cell organization and the microenvironment, and with the intracellular dynamics of miR-451-AMPK-mTOR signaling within a tumour cell. The model identifies a key mechanism underlying the molecular switches between proliferative phase and migratory phase in response to metabolic stress and biophysical interaction between cells in response to fluctuating glucose levels in the presence of blood vessels (BVs). The model predicts that cell migration, therefore efficacy of the treatment, not only depends on oxygen and glucose availability but also on the relative balance between random motility and strength of chemoattractants. Effective control of growing cells near BV sites in addition to relocalization of invisible migratory cells back to the resection site was suggested as a way of eradicating these migratory cells.
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Affiliation(s)
- Yangjin Kim
- Department of Mathematics, Konkuk University, Seoul, 143-701, Republic of Korea
- Department of Mathematics, Ohio State University, Columbus, OH 43210, USA
- * E-mail:
| | - Gibin Powathil
- Division of Mathematics, University of Dundee, Dundee, UK
- Department of Mathematics, Swansea University, Swansea, UK
| | - Hyunji Kang
- Department of Mathematics, Konkuk University, Seoul, 143-701, Republic of Korea
| | - Dumitru Trucu
- Division of Mathematics, University of Dundee, Dundee, UK
| | - Hyeongi Kim
- Department of Physics, Konkuk University, Seoul, 143-701, Republic of Korea
| | - Sean Lawler
- Department of Neurosurgery, Brigham and Women’s Hospital, Harvard Medical School, Boston MA 02115, USA
| | - Mark Chaplain
- Division of Mathematics, University of Dundee, Dundee, UK
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