Fluorescence Analysis of Taxol-Induced Paraptosis-Like Independent of Caspase-3 Activation

In the present report, the authors for the first time described the characteristics of taxol-induced paraptosis-like for the human lung adenocarcinoma cells (ASTC-a-1). CCK-8 was used to assay the inhibition of taxol on the cells viability. Cell viability was inhibited obviously 24 h after taxol treatment. Confocal fluorescence scanning microscope was used to monitor the morphology changes in cells with taxol treatment. Fluorescence resonance energy transfer (FRET) and acceptor photobleaching techniques were used to analyze the caspase-3 activation in the taxol-induced cell swelling and cell dearth. Taxol induced cell swelling, cytoplasmatic vacuolization and cell death without cell shrinkage, an apoptotic feature, and membrane rupture, a necrotic feature. The emission spectra of scat3 inside living cells expressed stably with scat3 were the same for control (without taxol). Further analysis with FRET and acceptor photobleaching techniques showed that the caspase-3 was not activated by taxol for the cytoplastic vacuoliazation cells expressed stably with scat3 plasmid, suggesting that caspase-3 is not involved in the taxol-inducecd cell swelling, cytoplasmatic vacuolization and cell death. These results show that taxol can induce a novel nonapoptotic PCD resembling the paraptosis in ASTC-a-1 cells.