Data on the effects of ECM rigidity on actomyosin contractility and invadopodia activity in individual versus pairs of head and neck squamous cell carcinoma cells

Migration through the extracellular matrix (ECM) is essential for cancer cells to escape the primary tumor and invade neighboring tissues with the potential for metastasis [1]. To penetrate tissue barriers, migrating cancer cells degrade the ECM with actin-rich membrane protrusions called invadopodia [2]. We have previously found that invadopodial ECM degradation is regulated by ECM rigidity in a process mediated by contractile forces in individual head and neck squamous cell carcinoma (HNSCC) cells [3], [4]. However, cancer cells often migrate together and interact with each other to alter their actomyosin contractility in response to the biomechanical properties of the ECM [5]. Therefore, we tested whether ECM rigidity promotes biomechanical interactions between cancer cells to enhance proteolytic activity. Using a minimal model of two HNSCC cells in physical contact, we provide data here that actomyosin contractility, invadopodia formation, and ECM degradation increase in response to ECM rigidity when cells are in pairs versus individual cells using traction force and invadopodia assays.