Bioactive C21 Steroidal Glycosides from Euphorbia kansui Promoted HepG2 Cell Apoptosis via the Degradation of ATP1A1 and Inhibited Macrophage Polarization under Co-Cultivation

Euphorbia kansuiis clinically used for the treatment of esophageal cancer, lung cancer, cancerous melanoma, asthma, pleural disorders, ascites, and pertussis, among other conditions. In this study, 12 steroids were obtained and identified fromE. kansui, and cynsaccatol L (5), which showed the best effects in terms of inhibiting the proliferation of HepG2 cells and the immune regulation of macrophages. Furthermore,5induced typical apoptotic characteristics in HepG2 cells, such as morphological changes and the caspase cascade, as well as inducing autophagy-dependent apoptosis via mitochondrial dysfunction and reactive oxygen species (ROS) accumulation. The antitumor mechanism of5might be related to promoting the endocytosis and degradation of ATP1A1 protein and then down-regulating the downstream AKT and ERK signaling pathways. Furthermore, the antiproliferation effect of5in co-cultivation with macrophages was investigated, which showed that5promoted the apoptosis of HepG2 cells by modulating the release of inflammatory cytokines, such as TNF-α and IFN-γ; regulating the M2-subtype polarization of macrophages; promoting the phagocytosis of macrophages. In conclusion,5exerted anti-proliferative effects by promoting the degradation of ATP1A1 and inhibiting the ATP1A1-AKT/ERK signaling pathway in HepG2. Furthermore, it regulated macrophage function in co-cultivation, thereby further exerting adjuvant anti-HepG2 activity.Keywords:Euphorbia kansui;antitumor;immunomodulatory;Na+, K+-ATPase;α1 subunit of NAK;dual antitumor activity