title: 3D traction stresses activate protease-dependent invasion of cancer cells.
abstract: Cell invasion and migration that occurs, for example, in cancer metastasis is rooted in the ability of cells to navigate through varying levels of physical constraint exerted by the extracellular matrix. Cancer cells can invade matrices in either a protease-independent or a protease-dependent manner. An emerging critical component that influences the mode of cell invasion is the traction stresses generated by the cells in response to the physicostructural properties of the extracellular matrix. In this study, we have developed a reference-free quantitative assay for measuring three-dimensional (3D) traction stresses generated by cells during the initial stages of invasion into matrices exerting varying levels of mechanical resistance. Our results show that as cells encounter higher mechanical resistance, a larger fraction of them shift to protease-mediated invasion, and this process begins at lower values of cell invasion depth. On the other hand, the compressive stress generated by the cells at the onset of protease-mediated invasion is found to be independent of matrix stiffness, suggesting that 3D traction stress is a key factor in triggering protease-mediated cancer cell invasion. At low 3D compressive traction stresses, cells utilize bleb formation to indent the matrix in a protease independent manner. However, at higher stress values, cells utilize invadopodia-like structures to mediate protease-dependent invasion into the 3D matrix. The critical value of compressive traction stress at the transition from a protease-independent to a protease-dependent mode of invasion is found to be ∼165 Pa.
authors.affiliation: Department of Bioengineering, University of California-San Diego, La Jolla, California.
authors.forename: Aereas
authors.initials: A
authors.lastname: Aung
authors.affiliation: Department of Bioengineering, University of California-San Diego, La Jolla, California.
authors.forename: Young N
authors.initials: YN
authors.lastname: Seo
authors.affiliation: Department of Bioengineering, University of California-San Diego, La Jolla, California.
authors.forename: Shaoying
authors.initials: S
authors.lastname: Lu
authors.affiliation: Department of Bioengineering, University of California-San Diego, La Jolla, California.
authors.forename: Yingxiao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Bioengineering, University of California-San Diego, La Jolla, California; IFOM-inStem Joint Research Laboratory, Bangalore, India.
authors.forename: Colin
authors.initials: C
authors.lastname: Jamora
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of California-San Diego, La Jolla, California; Institute of Engineering in Medicine, University of California-San Diego, La Jolla, California. Electronic address: jalamo@ucsd.edu.
authors.forename: Juan C
authors.initials: JC
authors.lastname: del Álamo
authors.affiliation: Department of Bioengineering, University of California-San Diego, La Jolla, California; Institute of Engineering in Medicine, University of California-San Diego, La Jolla, California; IFOM-inStem Joint Research Laboratory, Bangalore, India. Electronic address: svarghese@ucsd.edu.
authors.forename: Shyni
authors.initials: S
authors.lastname: Varghese
mesh_terms: D001696:Biomechanical Phenomena / Q000187:drug effects; D045744:Cell Line, Tumor; D003094:Collagen / Q000494:pharmacology; D004338:Drug Combinations; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007797:Laminin / Q000494:pharmacology; D009361:Neoplasm Invasiveness; D009369:Neoplasms / Q000473:pathology*; D010447:Peptide Hydrolases / Q000378:metabolism*; D011509:Proteoglycans / Q000494:pharmacology; D059010:Single-Cell Analysis; D013312:Stress, Physiological / Q000187:drug effects
chemical_list: D004338:Drug Combinations; D007797:Laminin; D011509:Proteoglycans; C059485:matrigel; D003094:Collagen; D010447:Peptide Hydrolases