Nuciferine inhibits the progression of glioblastoma by suppressing the SOX2-AKT/STAT3-Slug signaling pathway

BACKGROUND: Nuciferine (NF), extracted from the leaves of N. nucifera Gaertn, has been shown to exhibit anti-tumor and anti-viral pharmacological properties. It can also penetrate the blood brain barrier (BBB). However, the mechanism by which NF inhibits glioblastoma (GBM) progression is not well understood. We aimed to determine the anti-tumor effect of NF on GBM cell lines and clarify the potential molecular mechanism involved. METHODS: U87MG and U251 cell lines were used in vitro to assess the anti-tumor efficacy of NF. Cytotoxicity, viability, and proliferation were evaluated by MTT and colony formation assay. After Annexin V-FITC and PI staining, flow cytometry was performed to evaluate apoptosis and cell cycle changes in NF-treated GBM cells. Wound healing and Transwell assays were used to assess migration and invasion of GBM cells. Western blot analysis, immunofluorescence staining, immunohistochemistry, and bioinformatics were used to gain insights into the molecular mechanisms. Preclinical therapeutic efficacy was mainly estimated by ultrasound and MRI in xenograft nude mouse models. RESULTS: NF inhibited the proliferation, mobility, stemness, angiogenesis, and epithelial-to-mesenchymal transition (EMT) of GBM cells. Additionally, NF induced apoptosis and G2 cell cycle arrest. Slug expression was also decreased by NF via the AKT and STAT3 signaling pathways. Interestingly, we discovered that NF affected GBM cells partly by targeting SOX2, which may be upstream of the AKT and STAT3 pathways. Finally, NF led to significant tumor control in GBM xenograft models. CONCLUSIONS: NF inhibited the progression of GBM via the SOX2-AKT/STAT3-Slug signaling pathway. SOX2-targeting with NF may offer a novel therapeutic approach for GBM treatment. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13046-019-1134-y) contains supplementary material, which is available to authorized users.