Purpose: Dioscin, a natural glycoside derived from many plants, has been proved to exert anti-cancer activity. Several studies have found that it reverses TGF-β 1-induced epithelial–mesenchymal transition (EMT). Whether dioscin can reverse EMT by pathways other than TGF-β is still unknown.
Methods: We used network-based pharmacological methods to systematically explore the potential mechanisms by which dioscin acts on lung cancer. Cell Counting Kit-8 assay, scratch healing, Transwell assay, Matrigel invasion assay, immunofluorescence assay, and Western blotting were employed to confirm the prediction of key targets and the effects of dioscin on EMT.
Results: Here, using network-based pharmacological methods, we found 42 possible lung cancer-related targets of dioscin, which were assigned to 98 KEGG pathways. Among the 20 with the lowest p-values, the PI3K-AKT signaling pathway is involved and significantly related to EMT. AKT1 and mTOR, with high degrees (reflecting higher connectivity) in the compound-target analysis, participate in the PI3K-AKT signaling pathway. Molecular docking indicated the occurrence of dioscin-AKT1 and dioscin-mTOR binding. Functional experiments demonstrated that dioscin suppressed the proliferation, migration, invasion, and EMT of human lung adenocarcinoma cells in a dose-dependent manner, without TGF-β stimulation. Furthermore, we determined that dioscin downregulated p-AKT, p-mTOR and p-GSK3β in human lung adenocarcinoma cells without affecting their total protein levels. The PI3K inhibitor LY294002 augmented these changes.
Conclusion: Dioscin suppressed proliferation, invasion and EMT of lung adenocarcinoma cells via the inactivation of AKT/mTOR/GSK3β signaling, probably by binding to AKT and mTOR, and inhibiting their phosphorylation.
Keywords: dioscin, lung adenocarcinoma, epithelial–mesenchymal transition, network-based pharmacology