Gypenoside-Induced Apoptosis via the PI3K/AKT/mTOR Signaling Pathway in Bladder Cancer

Abstract

Gynostemma pentaphyllum (Thunb.) Makino (G. pentaphyllum) is a natural herbal drug that has been widely used to treat many diseases. The antitumor effects of G. pentaphyllum were first described in the illustrated catalog of plants. Gypenosides are the major active components of G. pentaphyllum, and they have been widely reported to possess antitumor effects in prostate cancer, gastric cancer, hepatocellular carcinoma, colon cancer, lung cancer, and breast cancer. However, research on the use of gypenoside in the treatment of bladder cancer has not been conducted. In this study, we explored the potential molecular mechanisms of gypenosides in the treatment of bladder cancer using network pharmacology and experimental validation. First, we used a network pharmacology–based method to identify both the effective components of gypenosides and the molecular mechanism underlying their antibladder cancer effects. The results were further confirmed by molecular docking, CCK8 and colony formation assays, and cell cycle and cell apoptosis analyses. Additionally, a mouse xenograft model of bladder cancer was used to investigate the antitumor effect of gypenosides in vivo. We identified 10 bioactive ingredients and 163 gene targets of gypenosides. Network exploration suggested that VEGFA, STAT3, and PI3KCA may be candidate agents for the antibladder cancer effect of gypenosides. In addition, analysis of the Kyoto Encyclopedia of Genes and Genomes pathway revealed that the phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway may play a crucial role in the mechanism of action of gypenosides against bladder cancer. Molecular docking revealed that gypenosides combine well with PI3K, AKT, and mTOR. As expected, gypenosides displayed apoptosis-inducing properties in bladder cancer cells by inactivating the PI3K/AKT/mTOR signaling pathway in vitro. Furthermore, gypenosides significantly ( $P<0.05$ ) inhibited the growth of bladder cancer cells in vivo. Mechanistically, gypenosides induced the apoptosis of bladder cancer cells via inactivation of the PI3K/AKT/mTOR signaling pathway.