Abstract

Although many chemotherapeutic agents induce neutrophil extracellular trap (NET) formation, how NETs affect therapeutic efficacy across different cancer types remains poorly understood. Here, we report that irinotecan-induced NETs exhibit differential cytotoxicity against cancer cells through the proteolytic activity of cathepsin G (CTSG), with colon cancer cells exhibiting high sensitivity while liver cancer cells demonstrating marked resistance. Through bioinformatic analysis and siRNA-mediated knockdown validation, we identified SERPINA3, a serine protease inhibitor, as a key factor in this resistance. Mechanistically, SERPINA3 inhibits CTSG-mediated cleavage of the anti-apoptotic protein 14-3-3ε, thereby protecting cells from NET-induced apoptosis. Interestingly, the NF-κB signaling pathway governs SERPINA3 expression in liver cancer cells, with activated p65 directly binding to its promoter. Targeting SERPINA3 with antisense oligonucleotides successfully sensitized liver cancer cells to irinotecan therapy. These findings elucidate a critical mechanism of chemoresistance in liver cancer and propose targeting SERPINA3 as a promising therapeutic strategy to enhance chemotherapy efficacy.