Jiaogulan (Gynostemma pentaphyllum) tea is a functional food that is commercially available worldwide. Gypensapogenin I (Gyp I), which is a natural damarane-type saponin, was obtained from the hydrolysates of total gypenosides. The present research was performed to investigate the potential antiproliferation effect of Gyp I in MDA-MB-231 cells and the underlying mechanisms. Here, we found that Gyp I attenuated survival, inhibited proliferation, and induced apoptosis in MDA-MB-231 cells. Target prediction by binding molecule docking and western blot assays confirmed the mechanism by which Gyp I inhibited the proliferation of breast cancer cells via the AKT/GSK3β/β-catenin signaling pathway. We also showed that Gyp I exhibited superior in vivo efficacy that was dose dependent. Tumor tissue transcriptome analysis indicated that Gyp I could decrease the expression levels of NOTCH1 and HES1, which was in contrast to the effect on MAML and NUMBL, indicating that our compound hindered the activation of the Notch-1 signaling pathway. In summary, we report for the first time that Gyp I shows excellent anti-breast cancer activity in vivo and in vitro and that its pathway of action is related to the AKT/GSK3β/β-catenin and Notch-1 signaling pathways. Therefore, Jiaogulan tea can not only be used as a health food but also possesses the possibility to treat triple-negative breast cancer (TNBC).
Keywords: AKT/GSK3β/β-catenin; Notch-1; gypensapogenin I; proliferation; triple-negative breast cancer.