Cytoskeletal Perturbing Drugs and Their Effect on Cell Elasticity
The cytoskeleton is primarily responsible for providing structural support, localization and transport of organelles, and intracellular trafficking. The structural support is supplied by actin filaments, microtubules, and intermediate filaments, which contribute to overall cell elasticity to varying degrees. We evaluate cell elasticity in five different cell types with drug-induced cytoskeletal derangements to probe how actin filaments and microtubules contribute to cell elasticity and whether it is conserved across cell type. Specifically, we measure elastic stiffness in chondrocytes, fibroblasts, endothelial cells, hepatocellular carcinoma, and fibrosarcoma using atomic force microscopy. We subject all five cell lines to two cytoskeletal destabilizers: cytochalasin D and nocodazole, which disrupt actin and microtubule polymerization, respectively. Non-cancer cells treated with cytochalasin D show a decrease of 60–80 % in moduli values compared to untreated cells of the same origin, whereas the nocodazole-treated cells show no change. Alternatively, cancer cells exhibit increased stiffness as well as stiffness variability when subjected to nocodazole. Overall, we demonstrate actin filaments contribute more to elastic stiffness than microtubules but this result is cell type dependent. Lastly, we show that disruption of microtubule dynamics affects cancer cell elasticity, suggesting therapeutic drugs targeting microtubules be monitored for significant elastic changes.
KeywordsAtomic force microscopy Cell mechanics Elasticity Cytoskeleton Cancer
The authors gratefully acknowledge our funding sources: ONR Grant N000141612100 (DME), the Provost’s Postdoctoral Fellowship for Academic Diversity (MEG), NSF-NSEC Grant DMR08-32802 (RJC), and URF 4-000002-4820 (DME), which made this work possible. The work was performed at and supported by the Nano Bio Interface Center at the University of Pennsylvania through an instrumentation grant, DBI-0721913, and DMR-0425780. We also thank Judith Kandel for cell culture training and Dr. Matt Brukman and Dr. Matt Caporizzo for instrument support. We thank the following for their generous donations: Dr. Robert Mauck (chondrocytes), Dr. Ben Stanger (HUH-7), and Dr. Bruce Malkowicz (HT-1080).
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