Research

Cell Adhesion, Migration, and Response to Mechanical Stimulation

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The image on the left shows a fibroblast cell stained for F-actin (red), zyxin (green) and DAPI (blue). Co-distribution of F-actin and zyxin is yellow. In the image on the right, fibroblasts were mechanically stimulated (uniaxial cyclic stretch) and stained for F-actin (green) and DNA (blue). The reinforced actin cytoskeleton aligns perpendicular to the horizontal stretch axis.

Cells respond to their environment by migrating towards or away from signals, adhering to their surroundings, proliferating or dying, and reinforcing their skeletal structure to withstand mechanical stresses. These signals and responses are highly regulated in normal cells, but certain controls may be lost in transformed cells, such as metastatic cancer cells. We are investigating how cells receive information, process it, and respond appropriately. Since many proteins are involved in these activities, we are determining how particular proteins contribute to the responses. One protein of interest, zyxin, is an actin cytoskeletal regulator, binds many other proteins and probably functions as a scaffolding protein to bring proteins together at the appropriate time and place. Zyxin is sensitive to the mechanical environment and adjusts its subcellular distribution in response to mechanical input. We are currently pursuing studies to characterize the role of zyxin and its many binding partners in cell adhesion, migration, cytoskeletal reinforcement and response to mechanical stimulation.

Selected References:

Zyxin: zinc fingers at sites of cell adhesion (1997) Bioessays

Mechanical force mobilizes zyxin from focal adhesions to actin filaments and regulates cytoskeletal reinforcement (2005) J Cell Biol

Stretch-induced actin remodeling requires targeting of zyxin to stress fibers and recruitment of actin regulators (2012) Mol Biol Cell

Tumor Progression and Metastasis

Tumor Progression and Metastasis

Ewing sarcoma cells expressing the EWS/FLI oncoprotein (left) or with knockdown of EWS/FLI (right) exhibit vastly different cell behavior. Cells were stained for F-actin (green) and the focal adhesion marker paxillin (magenta).

Ewing sarcoma is a pediatric bone tumor that is highly metastatic and resistant to therapy. The Beckerle Lab is working collaboratively with other research labs at the Huntsman Cancer Institute to determine the underlying mechanism of Ewing sarcoma pathogenesis with the hope that better understanding could lead to new treatment possibilities.

In Ewing sarcoma cells, the oncogenic transcription factor EWS/FLI activates and represses many genes. Using a knockdown/rescue approach to study the impact of EWS/FLI on cells, we identified dramatic EWS/FLI-dependent consequences in cell adhesion, migration and the actin cytoskeleton. Investigation of the molecular mechanisms behind these changes and development of pre-clinical models to evaluate Ewing sarcoma tumorigenesis and metastasis are underway, with the goal of improving options for therapeutic intervention.

Selected References:

The EWS/FLI Oncogene Drives Changes in Cellular Morphology, Adhesion, and Migration in Ewing Sarcoma (2012) Genes Cancer

Molecular dissection of the mechanism by which EWS/FLI expression compromises actin cytoskeletal integrity and cell adhesion in Ewing sarcoma (2014) Mol Biol Cell

Reversible LSD1 inhibition interferes with global EWS/ETS transcriptional activity and impedes Ewing sarcoma tumor growth (2014) Clin Cancer Res

Integrin signaling

Integrin Signaling

Fibroblast cells stained for the focal adhesion protein vinculin (red), cytoskeletal regulator zyxin (green), and the nucleus (blue). Co-distribution of vinculin and zyxin is yellow. Model showing proteins of interest localized to integrin-based focal adhesions.

Integrins (cell surface receptors that play a major role in communication between the intracellular and extracellular environments) affect cellular processes such as adhesion, migration proliferation, and survival. Integrins are critically important in developmental events, tissue maintenance, immune surveillance, and wound healing. Integrins also play key roles in diseases such as cancer, in which the interaction of tumor cells with their environment has far-reaching implications in tumor invasion and metastasis.

Upon binding of extracellular matrix (ECM), integrins cluster and recruit large signaling complexes to their cytoplasmic face that lead to alterations in both the actin cytoskeleton and gene expression. In turn, intracellular components can modulate the bining of integrins to the ECM. Scaffolding proteins, which mediate physical interactions with multiple protein partners, play an important role in signal integration by bringing together signaling molecules in a spatially and temporally regulated manner. We are currently working toward a molecular understanding of how binding of these partners contributes to integrin function, both in development and disease.

Reagent and Protocol Requests

To request reagents or protocols from the Beckerle Lab, please contact Chris Jensen.

Phone: 801-585-3872
email: chris.jensen@hci.utah.edu