Tumor invasion and metastasis are strongly regulated by biophysical interactions between tumor cells and the extracellular matrix (ECM). While the influence of ECM stiffness on cell migration, adhesion, and contractility has been extensively studied in two-dimensional (2D) culture, extension of these concepts to three- dimensional (3D) microenvironments characteristic of most tissues has proven extremely challenging given that manipulations normally used to vary ECM stiffness (e.g., variation of matrix and crosslink density) often concurrently alter matrix pore size (confinement), which can create steric barriers that regulate invasion speed independently of mechanics. To address this challenge, we have developed a novel matrix platform based on microfabrication of channels of defined wall stiffness and geometry that allows orthogonal variation of ECM stiffness and channel width. We have used this platform to characterize the regulation of glioblastoma cell invasion by ECM stiffness and confinement, which has led us to discover that stiff, narrow pores maximize cell invasion as a consequence of enhanced polarization of traction forces. As evidenced by this and other novel findings, this platform offers the best of both worlds with respect to experimental 2D and 3D cell migration paradigms, in that it retains the throughput, standardization, and screening power of the former while capturing key biophysical regulatory elements of the latter. With the support of this IMAT R21 award, we now propose to develop this platform as a microfluidic technology for high-throughput molecular screening and analysis. We will organize our research around three specific aims: (1) To develop an enclosed microfluidic device for the directed migration of tumor cells through channels of defined geometry and stiffness;(2) To use the platform to screen small molecule libraries for agents that slow migration in a stiffness- and confinement-dependent fashion;and (3) To relate invasion speed to gene expression in primary glioblastoma tumor initiating cells through comparative proteomic analysis. The proposed studies will address an unmet need for platforms capable of rapidly identifying drugs and genes that underlie physical microenvironmental control of tumor invasion. Ours is one of the first systematic efforts to study the roles of ECM stiffness and pore size (confinement) in regulating tumor cell invasion in 3D and to apply high-throughput molecular screening approaches to a problem in cell-ECM mechanobiology. By integrating mechanobiology, tumor stem cell biology, microfluidics, and proteomics, our work will create a valuable new discovery tool that is likely to open significant new translational opportunities for clinical oncology.

Public Health Relevance

The majority of cancer deaths are due to infiltration of tumor cells into tissue, which is fundamentally a process of cell migration through three-dimensional extracellular matrices. In this application we apply a novel microscale culture platform we have developed to orthogonally investigate contributions of extracellular matrix stiffness and microstructure to this process. We will adapt this technology for high-throughput cellular analysis, use it to screen small molecule and siRNA libraries for drugs and genes that alter cell invasion, and perform microscale protein analysis on glioblastoma tumor cells that navigate the device at various speeds to correlate invasive behavior with the expression and activity of proteins relevant to tumor stem cell biology, cell migration, and oncogenic signaling.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Exploratory/Developmental Grants (R21)
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Special Emphasis Panel (ZCA1-SRLB-Q (J1))
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Knowlton, John R
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University of California Berkeley
Biomedical Engineering
Schools of Engineering
United States
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Kassianidou, Elena; Hughes, Jasmine H; Kumar, Sanjay (2017) Activation of ROCK and MLCK tunes regional stress fiber formation and mechanics via preferential myosin light chain phosphorylation. Mol Biol Cell 28:3832-3843
Chen, Joseph; Kumar, Sanjay (2017) Biophysical Regulation of Cancer Stem/Initiating Cells: Implications for Disease Mechanisms and Translation. Curr Opin Biomed Eng 1:87-95
Lee, Jessica P; Kassianidou, Elena; MacDonald, James I et al. (2016) N-terminal specific conjugation of extracellular matrix proteins to 2-pyridinecarboxaldehyde functionalized polyacrylamide hydrogels. Biomaterials 102:268-76
Guillou, Lionel; Dahl, Joanna B; Lin, Jung-Ming G et al. (2016) Measuring Cell Viscoelastic Properties Using a Microfluidic Extensional Flow Device. Biophys J 111:2039-2050
Hughes, Jasmine Hannah; Kumar, Sanjay (2016) Synthetic mechanobiology: engineering cellular force generation and signaling. Curr Opin Biotechnol 40:82-89
Lee, Stacey; Kumar, Sanjay (2016) Actomyosin stress fiber mechanosensing in 2D and 3D. F1000Res 5:
Dahl, Joanna B; Narsimhan, Vivek; Gouveia, Bernardo et al. (2016) Experimental observation of the asymmetric instability of intermediate-reduced-volume vesicles in extensional flow. Soft Matter 12:3787-96
Rape, Andrew D; Zibinsky, Mikhail; Murthy, Niren et al. (2015) A synthetic hydrogel for the high-throughput study of cell-ECM interactions. Nat Commun 6:8129
Dahl, Joanna B; Lin, Jung-Ming G; Muller, Susan J et al. (2015) Microfluidic Strategies for Understanding the Mechanics of Cells and Cell-Mimetic Systems. Annu Rev Chem Biomol Eng 6:293-317
Wong, Sophie Y; Ulrich, Theresa A; Deleyrolle, Loic P et al. (2015) Constitutive activation of myosin-dependent contractility sensitizes glioma tumor-initiating cells to mechanical inputs and reduces tissue invasion. Cancer Res 75:1113-22

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