Taxol induces caspase-independent cytoplasmic vacuolization and cell death

High concentration of taxol induced programmed cell death (PCD) and cytoplasm vacuolization in human lung adenocarcinoma (ASTC-a-1) cells. To elucidate the relationship between the PCD and cytoplasm vacuolization, confocal fluorescence live imaging was performed on the dynamics of caspases activation and cytoplasm vacuolization. erRFP plasmid was used to probe the endoplasmic reticulum (ER), and SCAT3 plasmid was used to monitor the dynamics of caspase-3 activation in living cells. Our results showed that taxol induced concentration-dependent and caspases-independent cytoplasm vacuolization and cell death through ER and mitochondria swelling. Real-time confocal imaging of ASTC-a-1 cells stably expressing SCAT3 further verified that taxol-induced cytoplasm vacuolization and cell death was caspase3-independent. In conclusion, we found that taxol induces a paraptosis-like PCD in the ASTC-a-1 cells by cytoplasm vacuolization due to swelling of ER and mitochondria without activating the caspase enzymes.