DNA‐Based Single Molecule Force Sensor For Characterization of α 5 β 1 Integrin Tension Required for Invadopodia Formation and Maturation in Cancer Cells

Invadopodia are involved in cancer invasion by generating mechanical forces and secreting proteolytic enzymes. It is hypothesized that physical forces applied to integrin, especially α 5 β 1 integrin, are strongly associated with the generation of invadopodial forces and protrusive activity of invadopodia; however, their mechanical relationship remains elusive. Here, a new deoxyribonucleic acid‐based force probe is developed for mapping α 5 β 1 integrin tension with single‐molecule precision. Using this probe, the formation and maturation of invadopodia depending on integrin type and tension are investigated. In addition, the spatio‐temporal analysis of the integrin tension map is performed to measure changes in integrin tension and invadopodial force in each stage of invadopodia development. Consequently, it is found that α 5 β 1 integrin tension above 40 pN is critical not only for adhesion but also for the maturation of invadopodia, eventually leading to the generation of a strong invadopodial force greater than 100 pN through α 5 β 1 integrin‐ligand complexes with actomyosin contractility. This biophysical mechanism underlying the invadopodia formation and mechanical activation may provide new insights into cancer invasion and metastasis.