A novel non-nad-based PARP1 inhibitor, Japoflavone B, triggered Caspase-3/GSDME-mediated pyroptosis through ROS/p38/p53 pathway in NSCLC

It's an effective anti-cancer strategy to study natual products for activating GSDME-mediated pyroptosis through targeting PARP-1 in NSCLC. Previously, we found that a novel flavonoid Japoflavone B (JFB) has exhibited an excellent inhibitory activity against cancer cell proliferation in vitro study, but its in vivo and mechanism study are still unknown. Herein, JFB could specifically inhibit the proliferation of NSCLC cells, but not normal lung epithelial cells. JFB induced inflammatory pyroptosis through the activation of caspase-3 and GSDME cleavage. JFB also activated caspase-3/7/9 activities and triggered mitochondria-mediated apoptosis. Its inhibitory activity would be significantly reversed with the caspase-3 or GSDME deficiencies and their specific inhibitors. JFB could targetedly inhibit PARP-1 activity, and promote DNA damage and ROS accumulation. Meanwhile, JFB could significantly promote p-p38 and p53 expression. Then, JFB induced cell cycle G2/M arrest by reprogramming the expression of cyclins, CDKs and CKIs. Moreover, its cytotoxicity could be dramatically reversed with the ROS scavenger and p38 inhibitor. In vivo, JFB exhibited a comparable anti-tumor activity to that of Dox with no significant tissue toxicity. Our data firstly revealed that JFB functions as a selective and non-NAD-based PARP inhibitor with high affinity and low toxicology, which makes it potential to develop as a lead anti-cancer compound. As well, JFB promoted caspase-3/GSDME-mediated pyroptosis through ROS/p38/p53 pathway in NSCLC cells. Our study was further enriched the specific mechanism that PARP inhibitor could trigger caspase-3/GSDME-mediated pyroptosis through ROS/p38/p53 pathway in NSCLC cells. Overall design: To further reveal the molecular mechanism by which Japoflavone B activated caspase-mediated cell pyroptosis and apoptosis, the changes of gene mRNA expression levels after Japoflavone B treatment for 24h were detected by transcriptome sequencing compared with the control group.