Chemotherapeutic paclitaxel and cisplatin differentially induce pyroptosis in A549 lung cancer cells via caspase-3/GSDME activation

Gasdermin E (GSDME) has an important role in inducing secondary necrosis/pyroptosis. Upon apoptotic stimulation, it can be cleaved by activated caspase-3 to generate its N-terminal fragment (GSDME-NT), which executes pyroptosis by perforating the plasma membrane. GSDME is expressed in many human lung cancers including A549 cells. Paclitaxel and cisplatin are two representative chemotherapeutic agents for lung cancers, which induce apoptosis via different action mechanisms. However, it remains unclear whether they can induce GSDME-mediated secondary necrosis/pyroptosis in lung A549 cancer cells. Here we showed that both paclitaxel and cisplatin evidently induced apoptosis in A549 cells as revealed by the activation of multiple apoptotic markers. Notably, some of the dying cells displayed characteristic morphology of secondary necrosis/pyroptosis, by blowing large bubbles from the cellular membrane accompanied by caspase-3 activation and GSDME-NT generation. But the ability of cisplatin to induce this phenomenon was much stronger than that of paclitaxel. Consistent with this, cisplatin triggered much higher activation of caspase-3 and generation of GSDME-NT than paclitaxel, suggesting that the levels of secondary necrosis/pyroptosis correlated with the levels of active caspase-3 and GSDME-NT. Supporting this, caspase-3 specific inhibitor (Ac-DEVD-CHO) suppressed cisplatin-induced GSDME-NT generation and concurrently reduced the secondary necrosis/pyroptosis. Besides, GSDME knockdown significantly inhibited cisplatin- but not paclitaxel-induced secondary necrosis/pyroptosis. These results indicated that cisplatin induced higher levels of secondary necrosis/pyroptosis in A549 cells than paclitaxel, suggesting that cisplatin may provide additional advantages in the treatment of lung cancers with high levels of GSDME expression.