Discovery of Pyroptosis-inducing Drugs and Antineoplastic Activity Based on the ROS/ER Stress/Pyroptosis Axis

Background: Pyroptosis, a cell death process triggered by chemotherapy drugs, has emerged as a highly promising mechanism for combating tumors in recent years. As the lead of new drugs, natural products play an important role in the discovery of anticancer drugs. Compared to other natural products, the medicine food homologous natural products (MFHNP) exhibit a superior safety profile. Among a series of MFHNP molecular skeletons, this study found that only benzylideneacetophenone (1) could induce cancer cell pyroptosis. However, the anti-cancer activity of 1 remains to be improved. Aims: This study aimed to find a pyroptosis inducer with highly effective antitumor activity by modifying the chalcone structure. Methods: To examine the effect of the Michael receptor in compound 1 on the induction of pyroptosis, several analogs were synthesized by modifying the Michael acceptor. Subsequently, the anticancer activity was tested by MTT assay, and morphological indications of pyroptosis were observed in human lung carcinoma NCI-H460 and human ovarian cancer CP-70 cell lines. Furthermore, to improve the activity of the chalcone skeleton, the anticancer group 3,4,5- trimethoxyphenyl was incorporated into the phenyl ring. Subsequently, compounds 2-22 were designed, synthesized, and screened in human lung cancer cells (NCI-H460, H1975, and A549). Additionally, a quantitative structure-activity relationship (QSAR) model was established using the eXtreme Gradient Boosting (XGBoost) machine learning library to identify the pharmacophore. Furthermore, both in vitro and in vivo experiments were conducted to investigate the molecular mechanisms of pyroptosis induced by the active compound. Results: α, β-unsaturated ketone was the functional group of the chalcone skeleton and played a pivotal role in inducing cancer cell pyroptosis. QSAR models showed that the regression coefficients (R2) were 0.992 (A549 cells), 0.990 (NCI-H460 cells), and 0.998 (H1975 cells). Among these compounds, compound 7 was selected to be the active compound. Moreover, compound 7 was found to induce pyroptosis in lung cancer cells by upregulating the expression of CHOP by increasing the ROS level. Furthermore, it effectively suppressed the growth of lung cancer xenograft tumors. Conclusion: Compound 7 exhibits antineoplastic activity by regulating the ROS/ER stress/pyroptosis axis and is a kind of promising pyroptosis inducer.