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Extracellular biophysical cues such as matrix stiffness are key stimuli tuning cell fate and affecting tumor progression in vivo. However, it remains unclear how cancer spheroids in a 3D microenvironment perceive matrix mechanical stiffness stimuli and translate them into intracellular signals driving progression. Mechanosensitive Piezo1 and TRPV4 ion channels, upregulated in many malignancies, are major transducers of such physical stimuli into biochemical responses. Most mechanotransduction studies probing the reception of changing stiffness cues by cells are, however, still limited to 2D culture systems or cell-extracellular matrix models, which lack the major cell–cell interactions prevalent in 3D cancer tumors. Here, we engineered a 3D spheroid culture environment with varying mechanobiological properties to study the effect of static matrix stiffness stimuli on mechanosensitive and malignant phenotypes in oral squamous cell carcinoma spheroids. We find that spheroid growth is enhanced when cultured in stiff extracellular matrix. We show that the protein expression of mechanoreceptor Piezo1 and stemness marker CD44 is upregulated in stiff matrix. We also report the upregulation of a selection of genes with associations to mechanoreception, ion channel transport, extracellular matrix organization, and tumorigenic phenotypes in stiff matrix spheroids. Together, our results indicate that cancer cells in 3D spheroids utilize mechanosensitive ion channels Piezo1 and TRPV4 as means to sense changes in static extracellular matrix stiffness, and that stiffness drives pro-tumorigenic phenotypes in oral squamous cell carcinoma.
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Evaluating Nanoparticle Penetration In Tumor Spheroids
Introduction: The lack of an appropriate in vitro model of the tumor microenvironment is one of the largest obstacles in evaluating preclinical cancer drug screenings.1 Cancer cell monolayers do not effectively mimic the limited drug penetration properties of the complex tumor structures found in cancer patients. 3-D multicellular tumor spheroids (MCTS) serve as a more effective model as they better resemble cancer in structure as well as limited drug penetration. In our experiments, we created heterospheroids composed of 4T1 breast tumor cells and 3T3 fibroblasts, as well as homospheroids of each cell type. Tumors feature stromal and extracellular matrix components in addition to cancer cells in ratios that vary between different types of cancer. Fibroblasts are the major component of cancer stroma as well as producers of extracellular matrix. Since heterospheroids feature 3T3 fibroblasts, they may better model the diverse tumor microenvironment.2 We also synthesized fluorescent PLGA nanoparticles that were added to our spheroid cultures. Using confocal microscopy and ImageJ’s fluorescence measuring tools, we qualitatively and quantitatively evaluated the drug penetration properties of our spheroids.
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- Award ID(s):
- 1757885
- PAR ID:
- 10138551
- Date Published:
- Journal Name:
- 2019 BMES Conference Proceedings - REU Abstract Accepted Poster
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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