Anemoside B4 Inhibits Non-Small Cell Lung Cancer Metastasis by Intervening in MAPK and Keap1/Nrf2 Pathway-Mediated Epithelial-Mesenchymal Transition

<bold>Objective</bold>To investigate the effect and mechanism of Pulsatilla saponin B4 (AB4) on the metastasis of non-small cell lung cancer by regulating epithelial-mesenchymal transition (EMT).<bold>Methods</bold>In vitro, MTT assay was used to detect the effect of AB4 on the viability of A549 cells. Wound healing and Transwell assays were used to detect the effect of AB4 on the migration and invasion of TGF-β1-induced A549 cells. Western blot and immunofluorescence were used to detect the expression of EMT, MAPK and oxidative stress signaling pathway-related proteins. In vivo, a mouse lung cancer metastasis model was established by tail vein injection of B16-F10 cells. The effect of Pulsatilla saponin B4 (20, 40 mg/kg) on lung metastasis in mice was observed. Meanwhile, blood analyzer was used to detect blood indicators, HE staining was used to examine pathological changes in lung tissue, and Western blot was used to detect the expression of EMT, MAPK and oxidative stress signaling pathway-related proteins in lung tissue.<bold>Results</bold>In vitro experiments showed that Pulsatilla saponin B4 (5, 10, 20 μmol/L) had no cytotoxicity. Wound healing and Transwell assays showed that Pulsatilla saponin B4 could inhibit the migration and invasion of A549 cells, decrease the expression of N-cadherin, vimentin and transcription factors Slug and Snail in the EMT signaling pathway, and increase the expression of E-cadherin protein; decrease the expression of Keap1 in the oxidative stress signaling pathway and increase the expression of Nrf2; in addition, Pulsatilla saponin B4 could decrease the protein levels of p-JNK, p-ERK and p-p38 in the MAPK signaling pathway (all P&lt;0.05). In vivo experiments showed that Pulsatilla saponin B4 could alleviate the weight loss in mice, inhibit melanoma lung metastasis, had no significant effect on blood indicators in mice, inhibited the EMT, Nrf2 and MAPK signaling pathways in lung tissue of model mice, and reduced the lung metastasis of B16-F10 melanoma.<bold>Conclusion</bold>Pulsatilla saponin B4 inhibits lung metastasis by inhibiting the expression of EMT marker proteins and regulating the MAPK and Keap1/Nrf2 pathways.