A Microfluidic Platform for Studying Roles of Mechanical Compression in Tumor-Immune Cell Interactions in a 3D...

Mechanical forces significantly influence the ability of immune cells to kill tumor cells in the context of cell-based immunotherapy. To kill tumor cells, immune cells must exert forces on the target cell and form an immune synapse, through which cytotoxic molecules -including granzyme B-are delivered. Despite their importance, how mechanical cues can be leveraged to enhance immune-mediated killing remains poorly understood. This knowledge gap is partly due to the lack of tools capable of providing well-controlled mechanical stress to cell cultures in a physiologically realistic environment. Here, we describe a microfluidic compression device that can apply static or dynamic compression to tumor spheroids embedded in extracellular matrix (ECM) while enabling real-time imaging of tumor-immune interactions via optical microscopy. The microfluidic platform consists of 12 compartments (6 control and 6 functional). Each compartment contains a cell chamber positioned directly beneath the pressure control unit. Spheroids embedded in ECM are placed within the cell chamber. Using this platform, we investigated the killing efficiency of Natural Killer (NK) cells against breast tumor spheroids (MCF-7) under defined mechanical compression. The results showed that NK cells remained the primary drivers of tumor spheriods death regrardless of mechanical compression in 1.5 mg/mL collagen. Therefore, suggesting that NK cells can maintain their anti-tumor activity under compressive stress. These findings demonstrate the utility of this platform for investigating the role of mechanical forces in tumor-immune interactions. Ongoing studies are identifying the molecular mechanisms that allow immune cells to adapt to compressive stress. Insights gained from these studies may reveal a promising therapeutic avenue.