High throughput profiling drug response and apoptosis of single polar cells.

Single cell analysis has been used to reveal cellular heterogeneity and to gain deeper insight into some of life's mysteries. In this work, we developed a high throughput profiling platform for single polar cell analysis with controllable cell polarity on anisotropic microwell arrays. Due to the spatial confinement effect, the cells were individually trapped in the microwells and polarized to an assigned polarity (aspect ratio). Given the significance of polarity in biology, quantitative evaluation of the drug response on single polarized cells may provide guidance for chemotherapy. With this aim, we studied the interaction of the single polarized cells with drugs (doxorubicin and paclitaxel) to reveal the possible apoptosis mechanisms involved. Cell death features including cellular morphologies, nucleus pycnosis and the formation of inflammasome provided the indicators of programmed cell death and inflammatory death. To trace the apoptosis pathway, cell death enzyme cascades were quantitatively evaluated, especially the regulated cell death executor (caspase 3) and inflammatory death (caspase 1). The results showed that DOX killed the tumour cells not only through a regular cell death program, but also an inflammatory death pathway, while paclitaxel only led to a regular cell death program. Furthermore, the cells with different polarities respond to the drugs at different rates, namely the round cells (in their unpolarized phase) being the most sensitive to the drug molecules. These results provided significant information about guiding the treatment of tumours with chemotherapy.