651
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Gyger M, Stange R, Kießling TR, Fritsch A, Kostelnik KB, Beck-Sickinger AG, Zink M, Käs JA. Active contractions in single suspended epithelial cells. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2013; 43:11-23. [PMID: 24196420 DOI: 10.1007/s00249-013-0935-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/08/2013] [Accepted: 10/15/2013] [Indexed: 12/12/2022]
Abstract
Investigations of active contractions in tissue cells to date have been focused on cells that exert forces via adhesion sites to substrates or to other cells. In this study we show that also suspended epithelial cells exhibit contractility, revealing that contractions can occur independently of focal adhesions. We employ the Optical Stretcher to measure adhesion-independent mechanical properties of an epithelial cell line transfected with a heat-sensitive cation channel. During stretching the heat transferred to the ion channel causes a pronounced Ca(2+) influx through the plasma membrane that can be blocked by adequate drugs. This way the contractile forces in suspended cells are shown to be partially triggered by Ca(2+) signaling. A phenomenological mathematical model is presented, incorporating a term accounting for the active stress exerted by the cell, which is both necessary and sufficient to describe the observed increase in strain when the Ca(2+) influx is blocked. The median and the shape of the strain distributions depend on the activity of the cells. Hence, it is unlikely that they can be described by a simple Gaussian or log normal distribution, but depend on specific cellular properties such as active contractions. Our results underline the importance of considering activity when measuring cellular mechanical properties even in the absence of measurable contractions. Thus, the presented method to quantify active contractions of suspended cells offers new perspectives for a better understanding of cellular force generation with possible implications for medical diagnosis and therapy.
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Affiliation(s)
- Markus Gyger
- Abteilung für Physik der weichen Materie, Institut für Experimentelle Physik I, Universität Leipzig, Linnéstr. 5, 04103, Leipzig, Germany,
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652
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Bodensiek K, Li W, Sánchez P, Nawaz S, Schaap IAT. A high-speed vertical optical trap for the mechanical testing of living cells at piconewton forces. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:113707. [PMID: 24289404 DOI: 10.1063/1.4832036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Although atomic force microscopy is often the method of choice to probe the mechanical response of (sub)micrometer sized biomaterials, the lowest force that can be reliably controlled is limited to ≈0.1 nN. For soft biological samples, like cells, such forces can already lead to a strain large enough to enter the non-elastic deformation regime. To be able to investigate the response of single cells at lower forces we developed a vertical optical trap. The force can be controlled down to single piconewtons and most of the advantages of atomic force microscopy are maintained, such as the symmetrical application of forces at a wide range of loading rates. Typical consequences of moving the focus in the vertical direction, like the interferometric effect between the bead and the coverslip and a shift of focus, were quantified and found to have negligible effects on our measurements. With a fast responding force feedback loop we can achieve deformation rates as high as 50 μm/s, which allow the investigation of the elastic and viscous components of very soft samples. The potential of the vertical optical trap is demonstrated by measuring the linearity of the response of single cells at very low forces and a high bandwidth of deformation rates.
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Affiliation(s)
- Kai Bodensiek
- III. Physikalisches Institut, Georg-August-Universität, Göttingen, Germany
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653
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Ren J, Yu S, Gao N, Zou Q. Indentation quantification for in-liquid nanomechanical measurement of soft material using an atomic force microscope: rate-dependent elastic modulus of live cells. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:052711. [PMID: 24329300 PMCID: PMC4172360 DOI: 10.1103/physreve.88.052711] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 07/26/2013] [Indexed: 05/25/2023]
Abstract
In this paper, a control-based approach to replace the conventional method to achieve accurate indentation quantification is proposed for nanomechanical measurement of live cells using atomic force microscope. Accurate indentation quantification is central to probe-based nanomechanical property measurement. The conventional method for in-liquid nanomechanical measurement of live cells, however, fails to accurately quantify the indentation as effects of the relative probe acceleration and the hydrodynamic force are not addressed. As a result, significant errors and uncertainties are induced in the nanomechanical properties measured. In this paper, a control-based approach is proposed to account for these adverse effects by tracking the same excitation force profile on both a live cell and a hard reference sample through the use of an advanced control technique, and by quantifying the indentation from the difference of the cantilever base displacement in these two measurements. The proposed control-based approach not only eliminates the relative probe acceleration effect with no need to calibrate the parameters involved, but it also reduces the hydrodynamic force effect significantly when the force load rate becomes high. We further hypothesize that, by using the proposed control-based approach, the rate-dependent elastic modulus of live human epithelial cells under different stress conditions can be reliably quantified to predict the elasticity evolution of cell membranes, and hence can be used to predict cellular behaviors. By implementing the proposed approach, the elastic modulus of HeLa cells before and after the stress process were quantified as the force load rate was changed over three orders of magnitude from 0.1 to 100 Hz, where the amplitude of the applied force and the indentation were at 0.4-2 nN and 250-450 nm, respectively. The measured elastic modulus of HeLa cells showed a clear power-law dependence on the load rate, both before and after the stress process. Moreover, the elastic modulus of HeLa cells was substantially reduced by two to five times due to the stress process. Thus, our measurements demonstrate that the control-based protocol is effective in quantifying and characterizing the evolution of nanomechanical properties during the stress process of live cells.
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Affiliation(s)
- Juan Ren
- Department of Mechanical and Aerospace Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854, USA
| | - Shiyan Yu
- Department of Biological Sciences, Rutgers, The State University of New Jersey, Newark, New Jersey 07102, USA
| | - Nan Gao
- Department of Biological Sciences, Rutgers, The State University of New Jersey, Newark, New Jersey 07102, USA
| | - Qingze Zou
- Department of Mechanical and Aerospace Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey 08854, USA
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654
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Keratins significantly contribute to cell stiffness and impact invasive behavior. Proc Natl Acad Sci U S A 2013; 110:18507-12. [PMID: 24167274 DOI: 10.1073/pnas.1310493110] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Cell motility and cell shape adaptations are crucial during wound healing, inflammation, and malignant progression. These processes require the remodeling of the keratin cytoskeleton to facilitate cell-cell and cell-matrix adhesion. However, the role of keratins for biomechanical properties and invasion of epithelial cells is only partially understood. In this study, we address this issue in murine keratinocytes lacking all keratins on genome engineering. In contrast to predictions, keratin-free cells show about 60% higher cell deformability even for small deformations. This response is compared with the less pronounced softening effects for actin depolymerization induced via latrunculin A. To relate these findings with functional consequences, we use invasion and 3D growth assays. These experiments reveal higher invasiveness of keratin-free cells. Reexpression of a small amount of the keratin pair K5/K14 in keratin-free cells reverses the above phenotype for the invasion but does not with respect to cell deformability. Our data show a unique role of keratins as major players of cell stiffness, influencing invasion with implications for epidermal homeostasis and pathogenesis. This study supports the view that down-regulation of keratins observed during epithelial-mesenchymal transition directly contributes to the migratory and invasive behavior of tumor cells.
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655
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Pasqualato A, Lei V, Cucina A, Dinicola S, D'Anselmi F, Proietti S, Masiello MG, Palombo A, Bizzarri M. Shape in migration: quantitative image analysis of migrating chemoresistant HCT-8 colon cancer cells. Cell Adh Migr 2013; 7:450-9. [PMID: 24176801 DOI: 10.4161/cam.26765] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Unsuccessful cytotoxic anticancer treatments may contribute to tumor morphologic instability and consequent tissue invasion, promoting the selection of a more malignant phenotype. Indeed, morphological changes have been demonstrated to be more pronounced in strongly vs. weakly metastatic cells. By means of normalized bending energy, we have previously quantitatively defined the link between cell shape modifications and the acquisition of a more malignant phenotype by 5-FU-resistant colon cancer cells (HCT-8FUres). Such changes were significantly correlated with an increase in motility speed. Herein, we propose a method to quantitatively analyze the shape of wild and chemoresistant HCT-8 migration front cells during wound healing assay. We evaluated the reliability of parameters (area/perimeter ratio [A/p], circularity, roundness, fractal dimension, and solidity) in describing the biological behavior of the two cell lines, enabling hence in distinguishing the chemoresistant line from the other one. We found solidity index the parameter that better described the difference between chemoresistant and wild cells. Moreover, solidity is able to capture the differences between chemoresistant and wild cells at each time point of the migration process. Indeed, motility speed was found to be inversely correlated with solidity, a quantitative index of cell deformability. Deformability is an outstanding hallmark of the process leading to metastatic spread; consequently, solidity may be considered a marker of acquired metastatic property.
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Affiliation(s)
- Alessia Pasqualato
- Department of Surgery "P. Valdoni"; "Sapienza" University of Rome; Roma, Italy; Department of Neuroscience and Imaging; Section of Physiology and Physiopathology; University "G. d'Annunzio"; Chieti, Italy
| | | | - Alessandra Cucina
- Department of Surgery "P. Valdoni"; "Sapienza" University of Rome; Roma, Italy
| | - Simona Dinicola
- Department of Surgery "P. Valdoni"; "Sapienza" University of Rome; Roma, Italy; Department of Clinical and Molecular Medicine; "Sapienza" University of Rome; Roma, Italy
| | - Fabrizio D'Anselmi
- Department of Surgery "P. Valdoni"; "Sapienza" University of Rome; Roma, Italy; Department of Experimental Medicine; "Sapienza" University of Rome; Roma, Italy
| | - Sara Proietti
- Department of Surgery "P. Valdoni"; "Sapienza" University of Rome; Roma, Italy; Department of Clinical and Molecular Medicine; "Sapienza" University of Rome; Roma, Italy
| | - Maria Grazia Masiello
- Department of Surgery "P. Valdoni"; "Sapienza" University of Rome; Roma, Italy; Department of Clinical and Molecular Medicine; "Sapienza" University of Rome; Roma, Italy
| | - Alessandro Palombo
- Department of Surgery "P. Valdoni"; "Sapienza" University of Rome; Roma, Italy; University of Rome "Tor Vergata"; Roma, Italy
| | - Mariano Bizzarri
- Department of Experimental Medicine; "Sapienza" University of Rome; Roma, Italy
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656
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Wang G, Mao W, Byler R, Patel K, Henegar C, Alexeev A, Sulchek T. Stiffness dependent separation of cells in a microfluidic device. PLoS One 2013; 8:e75901. [PMID: 24146787 PMCID: PMC3797716 DOI: 10.1371/journal.pone.0075901] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 08/17/2013] [Indexed: 12/18/2022] Open
Abstract
Abnormal cell mechanical stiffness can point to the development of various diseases including cancers and infections. We report a new microfluidic technique for continuous cell separation utilizing variation in cell stiffness. We use a microfluidic channel decorated by periodic diagonal ridges that compress the flowing cells in rapid succession. The compression in combination with secondary flows in the ridged microfluidic channel translates each cell perpendicular to the channel axis in proportion to its stiffness. We demonstrate the physical principle of the cell sorting mechanism and show that our microfluidic approach can be effectively used to separate a variety of cell types which are similar in size but of different stiffnesses, spanning a range from 210 Pa to 23 kPa. Atomic force microscopy is used to directly measure the stiffness of the separated cells and we found that the trajectories in the microchannel correlated to stiffness. We have demonstrated that the current processing throughput is 250 cells per second. This microfluidic separation technique opens new ways for conducting rapid and low-cost cell analysis and disease diagnostics through biophysical markers.
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Affiliation(s)
- Gonghao Wang
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Wenbin Mao
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Rebecca Byler
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Krishna Patel
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Caitlin Henegar
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Alexander Alexeev
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Todd Sulchek
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- * E-mail:
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657
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Mitchell MJ, King MR. Physical biology in cancer. 3. The role of cell glycocalyx in vascular transport of circulating tumor cells. Am J Physiol Cell Physiol 2013; 306:C89-97. [PMID: 24133067 PMCID: PMC3919988 DOI: 10.1152/ajpcell.00285.2013] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Circulating tumor cells (CTCs) in blood are known to adhere to the luminal surface of the microvasculature via receptor-mediated adhesion, which contributes to the spread of cancer metastasis to anatomically distant organs. Such interactions between ligands on CTCs and endothelial cell-bound surface receptors are sensitive to receptor-ligand distances at the nanoscale. The sugar-rich coating expressed on the surface of CTCs and endothelial cells, known as the glycocalyx, serves as a physical structure that can control the spacing and, thus, the availability of such receptor-ligand interactions. The cancer cell glycocalyx can also regulate the ability of therapeutic ligands to bind to CTCs in the bloodstream. Here, we review the role of cell glycocalyx on the adhesion and therapeutic treatment of CTCs in the bloodstream.
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Affiliation(s)
- Michael J Mitchell
- Department of Biomedical Engineering, Cornell University, Ithaca, New York
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658
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Phillips KG, Kuhn P, McCarty OJT. Physical biology in cancer. 2. The physical biology of circulating tumor cells. Am J Physiol Cell Physiol 2013; 306:C80-8. [PMID: 24133063 DOI: 10.1152/ajpcell.00294.2013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The identification, isolation, and characterization of circulating tumor cells (CTCs) promises to enhance our understanding of the evolution of cancer in humans. CTCs provide a window into the hematogenous, or "fluid phase," of cancer, underlying the metastatic transition in which a locally contained tumor spreads to other locations in the body through the bloodstream. With the development of sensitive and specific CTC identification and isolation methodologies, the role of CTCs in clinical diagnostics, disease surveillance, and the physical basis of metastasis continues to be established. This review focuses on the quantification of the basic biophysical properties of CTCs and the use of these metrics to understand the hematogenous dissemination of these enigmatic cells.
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Affiliation(s)
- Kevin G Phillips
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, Oregon
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659
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Affiliation(s)
- Marie-Emilie Terret
- CIRB; Collège de France and CNRS-UMR7241 and INSERM-U1050; Paris, France; Equipe Labellisée Ligue Contre le Cancer; Paris, France; Memolife Laboratory of Excellence and Paris Science Lettre; Paris, France
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660
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Dudani JS, Gossett DR, Tse HTK, Di Carlo D. Pinched-flow hydrodynamic stretching of single-cells. LAB ON A CHIP 2013; 13:3728-34. [PMID: 23884381 DOI: 10.1039/c3lc50649e] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Reorganization of cytoskeletal networks, condensation and decondensation of chromatin, and other whole cell structural changes often accompany changes in cell state and can reflect underlying disease processes. As such, the observable mechanical properties, or mechanophenotype, which is closely linked to intracellular architecture, can be a useful label-free biomarker of disease. In order to make use of this biomarker, a tool to measure cell mechanical properties should accurately characterize clinical specimens that consist of heterogeneous cell populations or contain small diseased subpopulations. Because of the heterogeneity and potential for rare populations in clinical samples, single-cell, high-throughput assays are ideally suited. Hydrodynamic stretching has recently emerged as a powerful method for carrying out mechanical phenotyping. Importantly, this method operates independently of molecular probes, reducing cost and sample preparation time, and yields information-rich signatures of cell populations through significant image analysis automation, promoting more widespread adoption. In this work, we present an alternative mode of hydrodynamic stretching where inertially-focused cells are squeezed in flow by perpendicular high-speed pinch flows that are extracted from the single inputted cell suspension. The pinched-flow stretching method reveals expected differences in cell deformability in two model systems. Furthermore, hydraulic circuit design is used to tune stretching forces and carry out multiple stretching modes (pinched-flow and extensional) in the same microfluidic channel with a single fluid input. The ability to create a self-sheathing flow from a single input solution should have general utility for other cytometry systems and the pinched-flow design enables an order of magnitude higher throughput (65,000 cells s(-1)) compared to our previously reported deformability cytometry method, which will be especially useful for identification of rare cell populations in clinical body fluids in the future.
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Affiliation(s)
- Jaideep S Dudani
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California 90095, USA
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661
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Babahosseini H, Roberts PC, Schmelz EM, Agah M. Bioactive sphingolipid metabolites modulate ovarian cancer cell structural mechanics. Integr Biol (Camb) 2013; 5:1385-92. [PMID: 24056950 DOI: 10.1039/c3ib40121a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cancer progression is associated with an increased deformability of cancer cells and reduced resistance to mechanical forces, enabling motility and invasion. This is important for metastases survival and outgrowth and as such could be a target for chemopreventive strategies. In this study, we determined the differential effects of exogenous sphingolipid metabolites on the elastic modulus of mouse ovarian surface epithelial cells as they transition to cancer. Treatment with ceramide or sphingosine-1-phosphate in non-toxic concentrations decreased the average elastic modulus by 21% (p≤ 0.001) in transitional and 15% (p≤ 0.02) in aggressive stages while exerting no appreciable effect on non-malignant cells. In contrast, sphingosine treatment on average increased the elastic modulus by 33% (p≤ 0.0002) in aggressive cells while not affecting precursor cells. These results indicate that tumor-supporting sphingolipid metabolites act by making cells softer, while the anti-cancer metabolite sphingosine partially reverses the decreased elasticity associated with cancer progression. Thus, sphingosine may be a valid alternative to conventional chemotherapeutics in ovarian cancer prevention or treatment.
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Affiliation(s)
- Hesam Babahosseini
- Department of Mechanical Engineering, 100 Randolph Hall, Blacksburg, VA, USA.
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662
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Mak M, Erickson D. A serial micropipette microfluidic device with applications to cancer cell repeated deformation studies. Integr Biol (Camb) 2013; 5:1374-84. [PMID: 24056324 DOI: 10.1039/c3ib40128f] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cells are complex viscoelastic materials that are frequently in deformed morphological states, particularly during the cancer invasion process. The ability to study cell mechanical deformability in an accessible way can be enabling in many areas of research where biomechanics is important, from cancer metastasis to immune response to stem cell differentiation. Furthermore, phenomena in biology are frequently exhibited in high multiplicity. For instance, during metastasis, cells undergoing non-proteolytic invasion squeeze through a multitude of physiological barriers, including many small pores in the dense extracellular matrix (ECM) of the tumor stroma. Therefore, it is important to perform multiple measurements of the same property even for the same cell in order to fully appreciate its dynamics and variability, especially in the high recurrence regime. We have created a simple and minimalistic micropipette system with automated operational procedures that can sample the deformation and relaxation dynamics of single-cells serially and in a parallel manner. We demonstrated its ability to elucidate the impact of an initial cell deformation event on subsequent deformations for untreated and paclitaxel treated MDA-MB-231 metastatic breast cancer cells, and we examined contributions from the cell nucleus during whole-cell micropipette experiments. Finally we developed an empirical model that characterizes the serial factor, which describes the reduction in cost for cell deformations across sequential constrictions. We performed experiments using spatial, temporal, and force scales that match physiological and biomechanical processes, thus potentially enabling a qualitatively more pertinent representation of the functional attributes of cell deformability.
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Affiliation(s)
- Michael Mak
- Biomedical Engineering Department, Cornell University, Ithaca, NY 14853, USA
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663
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Unterkofler S, Garbos MK, Euser TG, St J Russell P. Long-distance laser propulsion and deformation- monitoring of cells in optofluidic photonic crystal fiber. JOURNAL OF BIOPHOTONICS 2013; 6:743-752. [PMID: 23281270 DOI: 10.1002/jbio.201200180] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 10/13/2012] [Accepted: 10/16/2012] [Indexed: 06/01/2023]
Abstract
We introduce a unique method for laser-propelling individual cells over distances of 10s of cm through stationary liquid in a microfluidic channel. This is achieved by using liquid-filled hollow-core photonic crystal fiber (HC-PCF). HC-PCF provides low-loss light guidance in a well-defined single mode, resulting in highly uniform optical trapping and propulsive forces in the core which at the same time acts as a microfluidic channel. Cells are trapped laterally at the center of the core, typically several microns away from the glass interface, which eliminates adherence effects and external perturbations. During propagation, the velocity of the cells is conveniently monitored using a non-imaging Doppler velocimetry technique. Dynamic changes in velocity at constant optical powers up to 350 mW indicate stress-induced changes in the shape of the cells, which is confirmed by bright-field microscopy. Our results suggest that HC-PCF will be useful as a new tool for the study of single-cell biomechanics.
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Affiliation(s)
- Sarah Unterkofler
- Max Planck Institute for the Science of Light, Guenther-Scharowsky-Str.1/Bldg. 24, 91058 Erlangen, Germany.
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664
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Esmaeilsabzali H, Beischlag TV, Cox ME, Parameswaran AM, Park EJ. Detection and isolation of circulating tumor cells: principles and methods. Biotechnol Adv 2013; 31:1063-84. [PMID: 23999357 DOI: 10.1016/j.biotechadv.2013.08.016] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/24/2013] [Accepted: 08/19/2013] [Indexed: 12/17/2022]
Abstract
Efforts to improve the clinical management of several cancers include finding better methods for the quantitative and qualitative analysis of circulating tumor cells (CTCs). However, detection and isolation of CTCs from the blood circulation is not a trivial task given their scarcity and the lack of reliable markers to identify these cells. With a variety of emerging technologies, a thorough review of the exploited principles and techniques as well as the trends observed in the development of these technologies can assist researchers to recognize the potential improvements and alternative approaches. To help better understand the related biological concepts, a simplified framework explaining cancer formation and its spread to other organs as well as how CTCs contribute to this process has been presented first. Then, based on their basic working-principles, the existing methods for detection and isolation of CTCs have been classified and reviewed as nucleic acid-based, physical properties-based and antibody-based methods. The review of literature suggests that antibody-based methods, particularly in conjunction with a microfluidic lab-on-a-chip setting, offer the highest overall performance for detection and isolation of CTCs. Further biological and engineering-related research is required to improve the existing methods. These include finding more specific markers for CTCs as well as enhancing the throughput, sensitivity, and analytic functionality of current devices.
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Affiliation(s)
- Hadi Esmaeilsabzali
- School of Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102nd Avenue, Surrey, V3T 0A3, BC, Canada; Faculty of Health Sciences, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, BC, Canada; School of Engineering Science, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, BC, Canada
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665
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Gyurkó DM, Veres DV, Módos D, Lenti K, Korcsmáros T, Csermely P. Adaptation and learning of molecular networks as a description of cancer development at the systems-level: Potential use in anti-cancer therapies. Semin Cancer Biol 2013; 23:262-9. [DOI: 10.1016/j.semcancer.2013.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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666
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Abstract
In the past decade, novel materials, probes and tools have enabled fundamental and applied cancer researchers to take a fresh look at the complex problem of tumour invasion and metastasis. These new tools, which include imaging modalities, controlled but complex in vitro culture conditions, and the ability to model and predict complex processes in vivo, represent an integration of traditional with novel engineering approaches; and their potential effect on quantitatively understanding tumour progression and invasion looks promising.
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Affiliation(s)
- Muhammad H Zaman
- The Department of Biomedical Engineering, Boston University, 44 Cummington Street, Boston MA 02215, USA.
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667
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Zhang W, Kai K, Ueno NT, Qin L. A Brief Review of the Biophysical Hallmarks of Metastatic Cancer Cells. ACTA ACUST UNITED AC 2013; 1:59-66. [PMID: 25309822 DOI: 10.1166/ch.2013.1010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A hallmark of metastatic cancer cells is their invasion through the basal membrane and endothelial layer, which requires a highly elastic cytoskeleton and nucleus. Therefore, cellular deformability can serve as a universal biophysical marker for detecting a tumor's propensity for invasion, migration, and metastasis. In this review, we define the importance of the biophysical features of cancer cells in tumor metastasis and summarize the state-of-the-art technology for the study of cell biomechanics. This review will serve as a brief introduction to the interdisciplinary character of cancer cell biophysics for cancer biologists, physicists, and engineers.
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Affiliation(s)
- Weijia Zhang
- Department of Nanomedicine, The Methodist Hospital Research Institute, Houston, TX 77030, USA ; Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA
| | - Kazuharu Kai
- Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, Breast Cancer Translational Research Laboratory, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Naoto T Ueno
- Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, Breast Cancer Translational Research Laboratory, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Lidong Qin
- Department of Nanomedicine, The Methodist Hospital Research Institute, Houston, TX 77030, USA ; Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA
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668
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Guo P, Cai B, Lei M, Liu Y, Fu BM. Differential arrest and adhesion of tumor cells and microbeads in the microvasculature. Biomech Model Mechanobiol 2013; 13:537-50. [PMID: 23880911 DOI: 10.1007/s10237-013-0515-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 07/10/2013] [Indexed: 01/21/2023]
Abstract
To investigate the mechanical mechanisms behind tumor cell arrest in the microvasculature, we injected fluorescently labeled human breast carcinoma cells or similarly sized rigid beads into the systemic circulation of a rat. Their arrest patterns in the microvasculature of mesentery were recorded and quantified. We found that 93% of rigid beads were arrested either at arteriole-capillary intersections or in capillaries. Only 3% were at the capillary-postcapillary venule intersections and in postcapillary venules. In contrast, most of the flexible tumor cells were either entrapped in capillaries or arrested at capillary or postcapillary venule-postcapillary venule intersections and in postcapillary venules. Only 12% of tumor cells were arrested at the arteriole-capillary intersections. The differential arrest and adhesion of tumor cells and microbeads in the microvasculature was confirmed by a χ(2) test (p < 0.001). These results demonstrate that mechanical trapping was responsible for almost all the arrest of beads and half the arrest of tumor cells. Based on the measured geometry and blood flow velocities at the intersections, we also performed a numerical simulation using commercial software (ANSYS CFX 12.01) to depict the detailed distribution profiles of the velocity, shear rate, and vorticity at the intersections where tumor cells preferred to arrest and adhere. Simulation results reveal the presence of localized vorticity and shear rate regions at the turning points of the microvessel intersections, implying that hemodynamic factors play an important role in tumor cell arrest in the microcirculation. Our study helps elucidate long-debated issues related to the dominant factors in early-stage tumor hematogenous metastasis.
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Affiliation(s)
- Peng Guo
- Department of Biomedical Engineering, The City College of the City University of New York, 160 Convent Avenue, New York, NY, 10031, USA
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669
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A soft cortex is essential for asymmetric spindle positioning in mouse oocytes. Nat Cell Biol 2013; 15:958-66. [PMID: 23851486 DOI: 10.1038/ncb2799] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 06/03/2013] [Indexed: 12/19/2022]
Abstract
At mitosis onset, cortical tension increases and cells round up, ensuring correct spindle morphogenesis and orientation. Thus, cortical tension sets up the geometric requirements of cell division. On the contrary, cortical tension decreases during meiotic divisions in mouse oocytes, a puzzling observation because oocytes are round cells, stable in shape, that actively position their spindles. We investigated the pathway leading to reduction in cortical tension and its significance for spindle positioning. We document a previously uncharacterized Arp2/3-dependent thickening of the cortical F-actin essential for first meiotic spindle migration to the cortex. Using micropipette aspiration, we show that cortical tension decreases during meiosis I, resulting from myosin-II exclusion from the cortex, and that cortical F-actin thickening promotes cortical plasticity. These events soften and relax the cortex. They are triggered by the Mos-MAPK pathway and coordinated temporally. Artificial cortex stiffening and theoretical modelling demonstrate that a soft cortex is essential for meiotic spindle positioning.
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670
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Zheng Y, Nguyen J, Wei Y, Sun Y. Recent advances in microfluidic techniques for single-cell biophysical characterization. LAB ON A CHIP 2013; 13:2464-83. [PMID: 23681312 DOI: 10.1039/c3lc50355k] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Biophysical (mechanical and electrical) properties of living cells have been proven to play important roles in the regulation of various biological activities at the molecular and cellular level, and can serve as promising label-free markers of cells' physiological states. In the past two decades, a number of research tools have been developed for understanding the association between the biophysical property changes of biological cells and human diseases; however, technical challenges of realizing high-throughput, robust and easy-to-perform measurements on single-cell biophysical properties have yet to be solved. In this paper, we review emerging tools enabled by microfluidic technologies for single-cell biophysical characterization. Different techniques are compared. The technical details, advantages, and limitations of various microfluidic devices are discussed.
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Affiliation(s)
- Yi Zheng
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
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671
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Unterberger MJ, Schmoller KM, Wurm C, Bausch AR, Holzapfel GA. Viscoelasticity of cross-linked actin networks: experimental tests, mechanical modeling and finite-element analysis. Acta Biomater 2013; 9:7343-53. [PMID: 23523535 DOI: 10.1016/j.actbio.2013.03.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 03/04/2013] [Accepted: 03/12/2013] [Indexed: 01/07/2023]
Abstract
Filamentous actin is one of the main constituents of the eukaryotic cytoskeleton. The actin cortex, a densely cross-linked network, resides underneath the lipid bilayer. In the present work we propose a continuum mechanical formulation for describing the viscoelastic properties of in vitro actin networks, which serve as model systems for the cortex, by including the microstructure, i.e. the behavior of a single filament and its spatial arrangement. The modeling of the viscoelastic response in terms of physically interpretable parameters is conducted using a multiscale approach consisting of two steps: modeling of the single filament response of F-actin by a worm-like chain model including the extensibility of the filament, and assembling the three-dimensional biopolymer network by using the microsphere model which accounts for filaments equally distributed in space. The viscoelastic effects of the network are taken into account using a generalized Maxwell model. The Cauchy stress and elasticity tensors are obtained within a continuum mechanics framework and implemented into a finite-element program. The model is validated on the network level using large strain experiments on reconstituted actin gels. Comparisons of the proposed model with rheological experiments recover reasonable values for the material parameters. Finite-element simulations of the indentation of a sphere on a network slab and the aspiration of a droplet in a micropipette allow for further insights of the viscoelastic behavior of actin networks.
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672
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Thomas G, Burnham NA, Camesano TA, Wen Q. Measuring the mechanical properties of living cells using atomic force microscopy. J Vis Exp 2013. [PMID: 23851674 DOI: 10.3791/50497] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mechanical properties of cells and extracellular matrix (ECM) play important roles in many biological processes including stem cell differentiation, tumor formation, and wound healing. Changes in stiffness of cells and ECM are often signs of changes in cell physiology or diseases in tissues. Hence, cell stiffness is an index to evaluate the status of cell cultures. Among the multitude of methods applied to measure the stiffness of cells and tissues, micro-indentation using an Atomic Force Microscope (AFM) provides a way to reliably measure the stiffness of living cells. This method has been widely applied to characterize the micro-scale stiffness for a variety of materials ranging from metal surfaces to soft biological tissues and cells. The basic principle of this method is to indent a cell with an AFM tip of selected geometry and measure the applied force from the bending of the AFM cantilever. Fitting the force-indentation curve to the Hertz model for the corresponding tip geometry can give quantitative measurements of material stiffness. This paper demonstrates the procedure to characterize the stiffness of living cells using AFM. Key steps including the process of AFM calibration, force-curve acquisition, and data analysis using a MATLAB routine are demonstrated. Limitations of this method are also discussed.
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Affiliation(s)
- Gawain Thomas
- Department of Physics, Worcester Polytechnic Institute
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673
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Pepin KM, Chen J, Glaser KJ, Mariappan YK, Reuland B, Ziesmer S, Carter R, Ansell SM, Ehman RL, McGee KP. MR elastography derived shear stiffness--a new imaging biomarker for the assessment of early tumor response to chemotherapy. Magn Reson Med 2013; 71:1834-40. [PMID: 23801372 DOI: 10.1002/mrm.24825] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 03/28/2013] [Accepted: 05/01/2013] [Indexed: 01/11/2023]
Abstract
PURPOSE The overall goal is to develop magnetic resonance elastography derived shear stiffness as a biomarker for the early identification of chemotherapy response, allowing dose, agent type and treatment regimen to be tailored on a per patient basis, improving therapeutic outcome and minimizing normal tissue toxicity. The specific purpose of this study is to test the feasibility of this novel biomarker to measure the treatment response in a well-known chemotherapy model. METHODS Tumors were grown in the right flank of genetically modified mice by subcutaneous injection of DoHH2 (non-Hodgkin's lymphoma) cells. Magnetic resonance elastography was used to quantify tumor stiffness before and after injection of a chemotherapeutic agent or saline. Histological tests were also performed on the tumors. RESULTS A significant decrease (P < 0.0001) in magnetic resonance elastography-derived tumor shear stiffness was observed within 4 days of chemotherapy treatment, while no appreciable change was observed in saline-treated tumors. No significant change in volume occurred at this early stage, but there were decreased levels of cellular proliferation in chemotherapy-treated tumors. CONCLUSION These results demonstrate that magnetic resonance elastography-derived estimates of shear stiffness reflect an initial response to cytotoxic therapy and suggest that this metric could be an early and sensitive biomarker of tumor response to chemotherapy.
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Affiliation(s)
- Kay M Pepin
- Department of Biomedical Engineering, Mayo Graduate School, Rochester, Minnesota, USA
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674
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Tamayo J, Kosaka PM, Ruz JJ, San Paulo Á, Calleja M. Biosensors based on nanomechanical systems. Chem Soc Rev 2013; 42:1287-311. [PMID: 23152052 DOI: 10.1039/c2cs35293a] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The advances in micro- and nanofabrication technologies enable the preparation of increasingly smaller mechanical transducers capable of detecting the forces, motion, mechanical properties and masses that emerge in biomolecular interactions and fundamental biological processes. Thus, biosensors based on nanomechanical systems have gained considerable relevance in the last decade. This review provides insight into the mechanical phenomena that occur in suspended mechanical structures when either biological adsorption or interactions take place on their surface. This review guides the reader through the parameters that change as a consequence of biomolecular adsorption: mass, surface stress, effective Young's modulus and viscoelasticity. The mathematical background needed to correctly interpret the output signals from nanomechanical biosensors is also outlined here. Other practical issues reviewed are the immobilization of biomolecular receptors on the surface of nanomechanical systems and methods to attain that in large arrays of sensors. We then describe some relevant realizations of biosensor devices based on nanomechanical systems that harness some of the mechanical effects cited above. We finally discuss the intrinsic detection limits of the devices and the limitation that arises from non-specific adsorption.
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Affiliation(s)
- Javier Tamayo
- Instituto de Microelectrónica de Madrid, CSIC, Isaac Newton 8 (PTM), Tres Cantos, 28760 Madrid, Spain
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675
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Katira P, Bonnecaze RT, Zaman MH. Modeling the mechanics of cancer: effect of changes in cellular and extra-cellular mechanical properties. Front Oncol 2013; 3:145. [PMID: 23781492 PMCID: PMC3678107 DOI: 10.3389/fonc.2013.00145] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 05/21/2013] [Indexed: 12/13/2022] Open
Abstract
Malignant transformation, though primarily driven by genetic mutations in cells, is also accompanied by specific changes in cellular and extra-cellular mechanical properties such as stiffness and adhesivity. As the transformed cells grow into tumors, they interact with their surroundings via physical contacts and the application of forces. These forces can lead to changes in the mechanical regulation of cell fate based on the mechanical properties of the cells and their surrounding environment. A comprehensive understanding of cancer progression requires the study of how specific changes in mechanical properties influences collective cell behavior during tumor growth and metastasis. Here we review some key results from computational models describing the effect of changes in cellular and extra-cellular mechanical properties and identify mechanistic pathways for cancer progression that can be targeted for the prediction, treatment, and prevention of cancer.
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Affiliation(s)
- Parag Katira
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Roger T. Bonnecaze
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Muhammad H. Zaman
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
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676
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Pokorný J, Foletti A, Kobilková J, Jandová A, Vrba J, Vrba J, Nedbalová M, Čoček A, Danani A, Tuszyński JA. Biophysical insights into cancer transformation and treatment. ScientificWorldJournal 2013; 2013:195028. [PMID: 23844381 PMCID: PMC3693169 DOI: 10.1155/2013/195028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 05/09/2013] [Indexed: 11/26/2022] Open
Abstract
Biological systems are hierarchically self-organized complex structures characterized by nonlinear interactions. Biochemical energy is transformed into work of physical forces required for various biological functions. We postulate that energy transduction depends on endogenous electrodynamic fields generated by microtubules. Microtubules and mitochondria colocalize in cells with microtubules providing tracks for mitochondrial movement. Besides energy transformation, mitochondria form a spatially distributed proton charge layer and a resultant strong static electric field, which causes water ordering in the surrounding cytosol. These effects create conditions for generation of coherent electrodynamic field. The metabolic energy transduction pathways are strongly affected in cancers. Mitochondrial dysfunction in cancer cells (Warburg effect) or in fibroblasts associated with cancer cells (reverse Warburg effect) results in decreased or increased power of the generated electromagnetic field, respectively, and shifted and rebuilt frequency spectra. Disturbed electrodynamic interaction forces between cancer and healthy cells may favor local invasion and metastasis. A therapeutic strategy of targeting dysfunctional mitochondria for restoration of their physiological functions makes it possible to switch on the natural apoptotic pathway blocked in cancer transformed cells. Experience with dichloroacetate in cancer treatment and reestablishment of the healthy state may help in the development of novel effective drugs aimed at the mitochondrial function.
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Affiliation(s)
- Jiří Pokorný
- Institute of Photonics and Electronics, Academy of Sciences of the Czech Republic, AS CR, Chaberská 57, 182 51 Prague 8-Kobylisy, Czech Republic.
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677
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Kim Y, Hong JW, Kim J, Shin JH. Comparative study on the differential mechanical properties of human liver cancer and normal cells. Anim Cells Syst (Seoul) 2013. [DOI: 10.1080/19768354.2013.789452] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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678
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Sarna M, Zadlo A, Pilat A, Olchawa M, Gkogkolou P, Burda K, Böhm M, Sarna T. Nanomechanical analysis of pigmented human melanoma cells. Pigment Cell Melanoma Res 2013; 26:727-30. [PMID: 23647844 DOI: 10.1111/pcmr.12113] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Accepted: 04/18/2013] [Indexed: 11/29/2022]
Abstract
Based on hitherto measurements of elasticity of various cells in vitro and ex vivo, cancer cells are generally believed to be much softer than their normal counterparts. In spite of significant research efforts on the elasticity of cancer cells, only few studies were undertaken with melanoma cells. However, there are no reports concerning pigmented melanoma cells. Here, we report for the first time on the elasticity of pigmented human melanoma cells. The obtained data show that melanin significantly increases the stiffness of pigmented melanoma cells and that the effect depends on the amount of melanin inside the cells. The dramatic impact of melanin on the nanomechanical properties of cells puts into question widely accepted paradigm about all cancer cells being softer than their normal counterparts. Our findings reveal significant limitations of the nanodiagnosis approach for melanoma and contribute to better understanding of cell elasticity.
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Affiliation(s)
- Michal Sarna
- Department of Medical Physics and Biophysics, Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Krakow, Poland.
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679
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Abstract
Experiments conducted in the microgravity environment of space are not typically at the forefront of the mind of a cancer biologist. However, space provides physical conditions that are not achievable on Earth, as well as conditions that can be exploited to study mechanisms and pathways that control cell growth and function. Over the past four decades, studies have shown how exposure to microgravity alters biological processes that may be relevant to cancer. In this Review, we explore the influence of microgravity on cell biology, focusing on tumour cells grown in space together with work carried out using models in ground-based investigations.
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680
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Roth KB, Eggleton CD, Neeves KB, Marr DWM. Measuring cell mechanics by optical alignment compression cytometry. LAB ON A CHIP 2013; 13:1571-1577. [PMID: 23440063 PMCID: PMC3623556 DOI: 10.1039/c3lc41253a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
To address the need for a high throughput, non-destructive technique for measuring individual cell mechanical properties, we have developed optical alignment compression (OAC) cytometry. OAC combines hydrodynamic drag in an extensional flow microfluidic device with optical forces created with an inexpensive diode laser to induce measurable deformations between compressed cells. In this, a low-intensity linear optical trap aligns incoming cells with the flow stagnation point allowing hydrodynamic drag to induce deformation during cell-cell interaction. With this novel approach, we measure cell mechanical properties with a throughput that improves significantly on current non-destructive individual cell testing methods.
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Affiliation(s)
- Kevin B. Roth
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, USA 80401
| | - Charles D. Eggleton
- Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, MD, USA 21250
| | - Keith B. Neeves
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, USA 80401
- Department of Pediatrics, University of Colorado, Denver, CO, USA 80045
| | - David W. M. Marr
- Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, CO, USA 80401
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681
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Piñón TM, Castelli AR, Hirst LS, Sharping JE. Fiber-optic trap-on-a-chip platform for probing low refractive index contrast biomaterials. APPLIED OPTICS 2013; 52:2340-2345. [PMID: 23670765 DOI: 10.1364/ao.52.002340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 03/06/2013] [Indexed: 06/02/2023]
Abstract
Dual-beam fiber trapping is a versatile technique for manipulating microparticles. We fabricate and evaluate the performance of a compact trap-on-a-chip design and demonstrate, for what we believe is the first time, trapping of low-contrast (m<1.005) lipid vesicles in solution. Counterpropagating fibers are fixed along the chip channel, and we calibrate the trap by optically displacing polystyrene microspheres from the trap center. Measured scattering forces are ~30-49 pN from each beam. Stable trapping and reversible deformation of lipid vesicles is demonstrated under femtonewton trapping forces. This chip has applications in probing a variety of soft biomaterials, such as biological cells, lipid membranes, and protein assemblies.
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Affiliation(s)
- Tessa M Piñón
- School of Engineering, University of California, Merced, California 95343, USA
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682
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AFM nanoindentation detection of the elastic modulus of tongue squamous carcinoma cells with different metastatic potentials. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2013; 9:864-74. [PMID: 23579203 DOI: 10.1016/j.nano.2013.04.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 03/30/2013] [Accepted: 04/01/2013] [Indexed: 12/11/2022]
Abstract
UNLABELLED Although significant advances have been made in understanding the molecular mechanisms that influence tongue squamous cell carcinoma (TSCC) metastasis, less is known about the association between the cellular elastic modulus and TSCC metastasis. Atomic force microscopy (AFM) nanoindentation via the rate-jump method was used to detect the elastic modulus of TSCC cells from patients and cell lines with different metastatic potentials. TSCC cells with higher metastatic potential showed decreases in the elastic modulus compared to TSCC cells with lower metastatic potential. Moreover, the decrease in elastic modulus was accompanied with epithelial-mesenchymal transition (EMT), cytoskeleton (F-actin and β-tubulin) changes, small nucleus size and large nucleus/cytoplasm (N/C) ratio. The present findings demonstrate a close relationship between the cellular elastic modulus and the metastasis of TSCC. The elastic modulus detected by AFM nanoindentation via the rate-jump method can potentially be used to grade the metastatic potential of TSCC. FROM THE CLINICAL EDITOR This team of investigators report the use of an atomic force microscopy-based method to determine the elastic modulus of tongue squamous cell carcinoma cells, and demonstrate that such cells with higher metastatic potential show decreased elastic modulus compared to cells with lower metastatic potential.
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683
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Actin-based biomechanical features of suspended normal and cancer cells. J Biosci Bioeng 2013; 116:380-5. [PMID: 23567154 DOI: 10.1016/j.jbiosc.2013.03.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 03/04/2013] [Accepted: 03/05/2013] [Indexed: 11/20/2022]
Abstract
The mechanical features of individual cells have been regarded as unique indicators of their states, which could constantly change in accordance with cellular events and diseases. Particularly, cancer progression was characterized by the disruption and/or reorganization of actin filaments causing mechanical changes. Thus, mechanical characterization of cells could become an effective cytotechnological approach for early detection of cancer. To develop mechanical cytotechnology, it would be necessary to clarify the mechanical properties in various cell adhesion states. In this study, we investigated the surface mechanical behavior of cancer and normal cells in the adherent and suspended states using atomic force microscopy. Adherent normal stromal cells showed high surface stiffness due to developed actin cap structures on their apical surface, whereas cancer cells did not have developed filamentous actin structures, and their surface stiffness was low. Upon cell detachment from the substrate, filamentous actin structures of adherent normal stromal cells reorganized to the cortical region and their surface stiffness decreased consequently however, the stiffness of suspended normal cells remained higher than that of cancer cells. These suspended state actin structures were similar, regardless of the cell type. Furthermore, the mechanical responses of the cancer and normal stromal cells to perturbation of the actin cytoskeleton were different, suggesting distinct regulatory mechanisms for actin cytoskeleton in cancer and normal cells in both adherent and suspended states. Therefore, cancer cells possess specific mechanical and actin cytoskeleton features different from normal stromal cells.
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684
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Optical tweezers for medical diagnostics. Anal Bioanal Chem 2013; 405:5671-7. [DOI: 10.1007/s00216-013-6919-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Revised: 03/11/2013] [Accepted: 03/14/2013] [Indexed: 12/18/2022]
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685
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Kiessling TR, Herrera M, Nnetu KD, Balzer EM, Girvan M, Fritsch AW, Martin SS, Käs JA, Losert W. Analysis of multiple physical parameters for mechanical phenotyping of living cells. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2013; 42:383-94. [PMID: 23504046 DOI: 10.1007/s00249-013-0888-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 12/13/2012] [Accepted: 01/09/2013] [Indexed: 01/12/2023]
Abstract
Since the cytoskeleton is known to regulate many cell functions, an increasing amount of effort to characterize cells by their mechanical properties has occured. Despite the structural complexity and dynamics of the multicomponent cytoskeleton, mechanical measurements on single cells are often fit to simple models with two to three parameters, and those parameters are recorded and reported. However, different simple models are likely needed to capture the distinct mechanical cell states, and additional parameters may be needed to capture the ability of cells to actively deform. Our new approach is to capture a much larger set of possibly redundant parameters from cells' mechanical measurement using multiple rheological models as well as dynamic deformation and image data. Principal component analysis and network-based approaches are used to group parameters to reduce redundancies and develop robust biomechanical phenotyping. Network representation of parameters allows for visual exploration of cells' complex mechanical system, and highlights unexpected connections between parameters. To demonstrate that our biomechanical phenotyping approach can detect subtle mechanical differences, we used a Microfluidic Optical Cell Stretcher to mechanically stretch circulating human breast tumor cells bearing genetically-engineered alterations in c-src tyrosine kinase activation, which is known to influence reattachment and invasion during metastasis.
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Affiliation(s)
- T R Kiessling
- Soft Matter Physics Division, Department of Physics and Earth Science, Institute of Experimental Physics I, Universität Leipzig, Linnéstrasse 5, 04103, Leipzig, Germany.
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686
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Microfluidic cytometer based on dual photodiode detection for cell size and deformability analysis. Talanta 2013; 111:178-82. [PMID: 23622542 DOI: 10.1016/j.talanta.2013.03.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 03/01/2013] [Indexed: 11/21/2022]
Abstract
Cellular mechanical properties play an important role in disease diagnosis. Distinguishing cells based on their mechanical properties provides a potential method for label-free diagnosis. In this work, a convenient and low-cost microfluidic cytometer was developed to study cell mechanical properties and cell size based on the change of transmission intensity, using a low-cost commercial laser as a light source and two photodiodes as detectors. The cells pass through a narrow microchannel with a width smaller than the cell dimension, integrated in a polydimethylsiloxane chip, below which the laser is focused. The transit time of individual cells is measured by the time difference detected by two photodiodes. This device was used to study the difference in cell mechanical properties between HL60 cells treated with and without Cytochalasin D. Furthermore, it was also applied to distinguish cells with different diameters, HL60 cells and red blood cells, by measuring the transmission intensity.
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687
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Eker B, Meissner R, Bertsch A, Mehta K, Renaud P. Label-free recognition of drug resistance via impedimetric screening of breast cancer cells. PLoS One 2013; 8:e57423. [PMID: 23483910 PMCID: PMC3587579 DOI: 10.1371/journal.pone.0057423] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 01/21/2013] [Indexed: 01/01/2023] Open
Abstract
We present a novel study on label-free recognition and distinction of drug resistant breast cancer cells (MCF-7 DOX) from their parental cells (MCF-7 WT) via impedimetric measurements. Drug resistant cells exhibited significant differences in their dielectric properties compared to wild-type cells, exerting much higher extracellular resistance (Rextra ). Immunostaining revealed that MCF-7 DOX cells gained a much denser F-actin network upon acquiring drug resistance indicating that remodeling of actin cytoskeleton is probably the reason behind higher Rextra , providing stronger cell architecture. Moreover, having exposed both cell types to doxorubicin, we were able to distinguish these two phenotypes based on their substantially different drug response. Interestingly, impedimetric measurements identified a concentration-dependent and reversible increase in cell stiffness in the presence of low non-lethal drug doses. Combined with a profound frequency analysis, these findings enabled distinguishing distinct cellular responses during drug exposure within four concentration ranges without using any labeling. Overall, this study highlights the possibility to differentiate drug resistant phenotypes from their parental cells and to assess their drug response by using microelectrodes, offering direct, real-time and noninvasive measurements of cell dependent parameters under drug exposure, hence providing a promising step for personalized medicine applications such as evaluation of the disease progress and optimization of the drug treatment of a patient during chemotherapy.
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Affiliation(s)
- Bilge Eker
- Laboratory of Microsystems (LMIS4), École polytechnique fédérale de Lausanne, Station 17, CH-1015 Lausanne, Switzerland.
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688
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Efremov YM, Dokrunova AA, Bagrov DV, Kudryashova KS, Sokolova OS, Shaitan KV. The effects of confluency on cell mechanical properties. J Biomech 2013; 46:1081-7. [PMID: 23453395 DOI: 10.1016/j.jbiomech.2013.01.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 12/27/2012] [Accepted: 01/21/2013] [Indexed: 11/17/2022]
Abstract
Mechanical properties of cells depend on various external and internal factors, like substrate stiffness and surface modifications, cell ageing and disease state. Some other currently unknown factors may exist. In this study we used force spectroscopy by AFM, confocal microscopy and flow cytometry to investigate the difference between single non-confluent and confluent (in monolayer) Vero cells. In all cases the stiffness values were fitted by log-normal rather than normal distribution. Log-normal distribution was also found for an amount of cortical actin in cells by flow cytometry. Cells in the monolayer were characterized by a significantly lower (1.4-1.7 times) Young's modulus and amount of cortical actin than in either of the single non-confluent cells or cells migrating in the experimental wound. Young's modulus as a function of indentation speed followed a weak power law for all the studied cell states, while the value of the exponent was higher for cells growing in monolayer. These results show that intercellular contacts and cell motile state significantly influence the cell mechanical properties.
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Affiliation(s)
- Yu M Efremov
- M.V. Lomonosov Moscow State University, Faculty of Biology, Department of Bioengineering, Leninskie Gory, 1/73, 111991 Moscow, Russia.
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689
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Mak M, Reinhart-King CA, Erickson D. Elucidating mechanical transition effects of invading cancer cells with a subnucleus-scaled microfluidic serial dimensional modulation device. LAB ON A CHIP 2013; 13:340-8. [PMID: 23212313 PMCID: PMC3750734 DOI: 10.1039/c2lc41117b] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Mechanical boundaries that define and regulate biological processes, such as cell-cell junctions and dense extracellular matrix networks, exist throughout the physiological landscape. During metastasis, cancer cells are able to invade across these barriers and spread to distant tissues. While transgressing boundaries is a necessary step for distal colonies to form, little is known about interface effects on cell behavior during invasion. Here we introduce a device and metric to assess cell transition effects across mechanical barriers. Using MDA-MB-231 cells, a highly metastatic breast adenocarcinoma cell line, our results demonstrate that dimensional modulation in confined spaces with mechanical barriers smaller than the cell nucleus can induce distinct invasion phases and elongated morphological states. Further investigations on the impact of microtubule stabilization and drug resistance reveal that taxol-treated cells have reduced ability in invading across tight spaces and lose their super-diffusive migratory state and taxol-resistant cells exhibit asymmetric cell division at barrier interfaces. These results illustrate that subnucleus-scaled confinement modulation can play a distinctive role in inducing behavioral responses in invading cells and can help reveal the mechanical elements of non-proteolytic invasion.
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Affiliation(s)
- Michael Mak
- Biomedical Engineering Department, Cornell University, Ithaca, NY, United States
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690
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Physical break-down of the classical view on cancer cell invasion and metastasis. Eur J Cell Biol 2013; 92:89-104. [PMID: 23391781 DOI: 10.1016/j.ejcb.2012.12.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/12/2012] [Accepted: 12/23/2012] [Indexed: 11/23/2022] Open
Abstract
Eight classical hallmarks of cancer have been proposed and are well-defined by using biochemical or molecular genetic methods, but are not yet precisely defined by cellular biophysical processes. To define the malignant transformation of neoplasms and finally reveal the functional pathway, which enables cancer cells to promote cancer progression, these classical hallmarks of cancer require the inclusion of specific biomechanical properties of cancer cells and their microenvironment such as the extracellular matrix and embedded cells such as fibroblasts, macrophages or endothelial cells. Nonetheless a main novel ninth hallmark of cancer is still elusive in classical tumor biological reviews, which is the aspect of physics in cancer disease by the natural selection of an aggressive (highly invasive) subtype of cancer cells. The physical aspects can be analyzed by using state-of-the-art biophysical methods. Thus, this review will present current cancer research in a different light and will focus on novel physical methods to investigate the aggressiveness of cancer cells from a biophysicist's point of view. This may lead to novel insights into cancer disease and will overcome classical views on cancer. In addition, this review will discuss how physics of cancer can help to reveal whether cancer cells will invade connective tissue and metastasize. In particular, this review will point out how physics can improve, break-down or support classical approaches to examine tumor growth even across primary tumor boundaries, the invasion of single or collective cancer cells, transendothelial migration of cancer cells and metastasis in targeted organs. Finally, this review will show how physical measurements can be integrated into classical tumor biological analysis approaches. The insights into physical interactions between cancer cells, the primary tumor and the microenvironment may help to solve some "old" questions in cancer disease progression and may finally lead to novel approaches for development and improvement of cancer diagnostics and therapies.
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691
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Bowman RW, Padgett MJ. Optical trapping and binding. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:026401. [PMID: 23302540 DOI: 10.1088/0034-4885/76/2/026401] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The phenomenon of light's momentum was first observed in the laboratory at the beginning of the twentieth century, and its potential for manipulating microscopic particles was demonstrated by Ashkin some 70 years later. Since that initial demonstration, and the seminal 1986 paper where a single-beam gradient-force trap was realized, optical trapping has been exploited as both a rich example of physical phenomena and a powerful tool for sensitive measurement. This review outlines the underlying theory of optical traps, and explores many of the physical observations that have been made in such systems. These phenomena include 'optical binding', where trapped objects interact with one another through the trapping light field. We also discuss a number of the applications of 'optical tweezers' across the physical and life sciences, as well as covering some of the issues involved in constructing and using such a tool.
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Affiliation(s)
- Richard W Bowman
- SUPA, School of Physics and Astronomy, University of Glasgow, G12 8QQ, UK.
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692
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Das T, Chakraborty S. Perspective: Flicking with flow: Can microfluidics revolutionize the cancer research? BIOMICROFLUIDICS 2013; 7:11811. [PMID: 24403993 PMCID: PMC3574074 DOI: 10.1063/1.4789750] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 12/20/2012] [Indexed: 06/01/2023]
Abstract
According to the World Health Organization, cancer is one of the leading causes of death worldwide. Cancer research, in its all facets, is truly interdisciplinary in nature, cutting across the fields of fundamental and applied sciences, as well as biomedical engineering. In recent years, microfluidics has been applied successfully in cancer research. There remain, however, many elusive features of this disease, where microfluidic systems could throw new lights. In addition, some inherent features of microfluidic systems remain unexploited in cancer research. In this article, we first briefly review the advancement of microfluidics in cancer biology. We then describe the biophysical aspects of cancer and outline how microfluidic system could be useful in developing a deeper understanding on the underlying mechanisms. We next illustrate the effects of the confined environment of microchannel on cellular dynamics and argue that the tissue microconfinement could be a crucial facet in tumor development. Lastly, we attempt to highlight some of the most important problems in cancer biology, to inspire next level of microfluidic applications in cancer research.
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Affiliation(s)
- Tamal Das
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, Stuttgart 70569, Germany
| | - Suman Chakraborty
- Department of Mechanical Engineering, Indian Institute for Technology Kharagpur, Kharagpur 721302, India
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693
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Abdolahad M, Mohajerzadeh S, Janmaleki M, Taghinejad H, Taghinejad M. Evaluation of the shear force of single cancer cells by vertically aligned carbon nanotubes suitable for metastasis diagnosis. Integr Biol (Camb) 2013; 5:535-42. [DOI: 10.1039/c2ib20215h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- M. Abdolahad
- Nano-Electronic Center of Excellence, Nano-Electronics and Thin Film Lab., School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395/515, Tehran Iran
- Science and Technology Park, University of Tehran, Tehran, Iran
| | - S. Mohajerzadeh
- Nano-Electronic Center of Excellence, Nano-Electronics and Thin Film Lab., School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395/515, Tehran Iran
- Science and Technology Park, University of Tehran, Tehran, Iran
| | - M. Janmaleki
- Medical Nanotechnology and Tissue Engineering Research Center, Shahid-Beheshti University of Medical Science, P.O. Box 1985717443, Tehran, Iran
| | - H. Taghinejad
- Nano-Electronic Center of Excellence, Nano-Electronics and Thin Film Lab., School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395/515, Tehran Iran
| | - M. Taghinejad
- Nano-Electronic Center of Excellence, Nano-Electronics and Thin Film Lab., School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395/515, Tehran Iran
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694
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Abstract
It is increasingly recognized that cell signaling, as a chemical process, must be considered at the local, micrometer scale. Micro- and nanofabrication techniques provide access to these dimensions, with the potential to capture and manipulate the spatial complexity of intracellular signaling in experimental models. This review focuses on recent advances in adapting surface engineering for use with biomolecular systems that interface with cell signaling, particularly with respect to surfaces that interact with multiple receptor systems on individual cells. The utility of this conceptual and experimental approach is demonstrated in the context of epithelial cells and T lymphocytes, two systems whose ability to perform their physiological function is dramatically impacted by the convergence and balance of multiple signaling pathways.
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Affiliation(s)
- L.C. Kam
- Deparment of Biomedical Engineering, Columbia University, New York, NY 10027
| | - K. Shen
- Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114;
| | - M.L. Dustin
- Molecular Pathogenesis Program, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016;
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695
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Khan ZS, Vanapalli SA. Probing the mechanical properties of brain cancer cells using a microfluidic cell squeezer device. BIOMICROFLUIDICS 2013; 7:11806. [PMID: 24403988 PMCID: PMC3555914 DOI: 10.1063/1.4774310] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 10/22/2012] [Indexed: 05/07/2023]
Abstract
Despite being invasive within surrounding brain tissues and the central nervous system, little is known about the mechanical properties of brain tumor cells in comparison with benign cells. Here, we present the first measurements of the peak pressure drop due to the passage of benign and cancerous brain cells through confined microchannels in a "microfluidic cell squeezer" device, as well as the elongation, speed, and entry time of the cells in confined channels. We find that cancerous and benign brain cells cannot be differentiated based on speeds or elongation. We have found that the entry time into a narrow constriction is a more sensitive indicator of the differences between malignant and healthy glial cells than pressure drops. Importantly, we also find that brain tumor cells take a longer time to squeeze through a constriction and migrate more slowly than benign cells in two dimensional wound healing assays. Based on these observations, we arrive at the surprising conclusion that the prevailing notion of extraneural cancer cells being more mechanically compliant than benign cells may not apply to brain cancer cells.
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Affiliation(s)
- Z S Khan
- Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA
| | - S A Vanapalli
- Chemical Engineering, Texas Tech University, Lubbock, Texas 79409, USA
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696
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Huber F, Schnauß J, Rönicke S, Rauch P, Müller K, Fütterer C, Käs J. Emergent complexity of the cytoskeleton: from single filaments to tissue. ADVANCES IN PHYSICS 2013; 62:1-112. [PMID: 24748680 PMCID: PMC3985726 DOI: 10.1080/00018732.2013.771509] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 01/11/2013] [Indexed: 05/17/2023]
Abstract
Despite their overwhelming complexity, living cells display a high degree of internal mechanical and functional organization which can largely be attributed to the intracellular biopolymer scaffold, the cytoskeleton. Being a very complex system far from thermodynamic equilibrium, the cytoskeleton's ability to organize is at the same time challenging and fascinating. The extensive amounts of frequently interacting cellular building blocks and their inherent multifunctionality permits highly adaptive behavior and obstructs a purely reductionist approach. Nevertheless (and despite the field's relative novelty), the physics approach has already proved to be extremely successful in revealing very fundamental concepts of cytoskeleton organization and behavior. This review aims at introducing the physics of the cytoskeleton ranging from single biopolymer filaments to multicellular organisms. Throughout this wide range of phenomena, the focus is set on the intertwined nature of the different physical scales (levels of complexity) that give rise to numerous emergent properties by means of self-organization or self-assembly.
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Affiliation(s)
- F. Huber
- Institute for Experimental Physics I, University of Leipzig, Leipzig, Germany
| | - J. Schnauß
- Institute for Experimental Physics I, University of Leipzig, Leipzig, Germany
| | - S. Rönicke
- Institute for Experimental Physics I, University of Leipzig, Leipzig, Germany
| | - P. Rauch
- Institute for Experimental Physics I, University of Leipzig, Leipzig, Germany
| | - K. Müller
- Institute for Experimental Physics I, University of Leipzig, Leipzig, Germany
| | - C. Fütterer
- Institute for Experimental Physics I, University of Leipzig, Leipzig, Germany
| | - J. Käs
- Institute for Experimental Physics I, University of Leipzig, Leipzig, Germany
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697
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Comparison of mechanical properties of normal and malignant thyroid cells. Micron 2012; 43:1267-72. [DOI: 10.1016/j.micron.2012.03.023] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 03/22/2012] [Accepted: 03/27/2012] [Indexed: 11/22/2022]
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698
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Tang X, Wen Q, Kuhlenschmidt TB, Kuhlenschmidt MS, Janmey PA, Saif TA. Attenuation of cell mechanosensitivity in colon cancer cells during in vitro metastasis. PLoS One 2012; 7:e50443. [PMID: 23226284 PMCID: PMC3511581 DOI: 10.1371/journal.pone.0050443] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 10/22/2012] [Indexed: 02/07/2023] Open
Abstract
Human colon carcinoma (HCT-8) cells show a stable transition from low to high metastatic state when cultured on appropriately soft substrates (21 kPa). Initially epithelial (E) in nature, the HCT-8 cells become rounded (R) after seven days of culture on soft substrate. R cells show a number of metastatic hallmarks [1]. Here, we use gradient stiffness substrates, a bio-MEMS force sensor, and Coulter counter assays to study mechanosensitivity and adhesion of E and R cells. We find that HCT-8 cells lose mechanosensitivity as they undergo E-to-R transition. HCT-8 R cells' stiffness, spread area, proliferation and migration become insensitive to substrate stiffness in contrast to their epithelial counterpart. They are softer, proliferative and migratory on all substrates. R cells show negligible cell-cell homotypic adhesion, as well as non-specific cell-substrate adhesion. Consequently they show the same spread area on all substrates in contrast to E cells. Taken together, these results indicate that R cells acquire autonomy and anchorage independence, and are thus potentially more invasive than E cells. To the best of our knowledge, this is the first report of quantitative data relating changes in cancer cell adhesion and stiffness during the expression of an in vitro metastasis-like phenotype.
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Affiliation(s)
- Xin Tang
- Department of Mechanical Science and Engineering, College of Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Qi Wen
- Departments of Physiology, Physics, and Bioengineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Theresa B. Kuhlenschmidt
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Mark S. Kuhlenschmidt
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Paul A. Janmey
- Departments of Physiology, Physics, and Bioengineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Taher A. Saif
- Department of Mechanical Science and Engineering, College of Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Micro and Nanotechnology Laboratory (MNTL), University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
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699
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700
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Modeling the influence of nucleus elasticity on cell invasion in fiber networks and microchannels. J Theor Biol 2012; 317:394-406. [PMID: 23147234 DOI: 10.1016/j.jtbi.2012.11.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 10/11/2012] [Accepted: 11/02/2012] [Indexed: 11/22/2022]
Abstract
Cell migration in highly constrained extracellular matrices is exploited in scaffold-based tissue engineering and is fundamental in a wide variety of physiological and pathological phenomena, among others in cancer invasion and development. Research into the critical processes involved in cell migration has mainly focused on cell adhesion and proteolytic degradation of the external environment. However, rising evidence has recently shown that a number of cell-derived biophysical and mechanical parameters, among others nucleus stiffness and cell deformability, plays a major role in cell motility, especially in the ameboid-like migration mode in 3D confined tissue structures. We here present an extended cellular Potts model (CPM) first used to simulate a micro-fabricated migration chip, which tests the active invasive behavior of cancer cells into narrow channels. As distinct features of our approach, cells are modeled as compartmentalized discrete objects, differentiated in the nucleus and in the cytosolic region, while the migration chamber is composed of channels of different widths. We find that cell motile phenotype and velocity in open spaces (i.e., 2D flat surfaces or large channels) are not significantly influenced by cell elastic properties. On the contrary, the migratory behavior of cells within subcellular and subnuclear structures strongly relies on the deformability of the cytosol and of the nuclear cluster, respectively. Further, we characterize two migration dynamics: a stepwise way, characterized by fluctuations in cell length, within channels smaller than nucleus dimensions and a smooth sliding (i.e., maintaining constant cell length) behavior within channels larger than the nuclear cluster. These resulting observations are then extended looking at cell migration in an artificial fiber network, which mimics cell invasion in a 3D extracellular matrix. In particular, in this case, we analyze the effect of variations in elasticity of the nucleus on cell movement. In order to summarize, with our simulated migration assays, we demonstrate that the dimensionality of the environment strongly affects the migration phenotype and we suggest that the cytoskeletal and nuclear elastic characteristics correlate with the tumor cell's invasive potential.
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