Mechanism of Key Ingredient of Astragalus membranaceus on Lung Adenocarcinoma via PI3K/AKT Signaling Clarified by Utilizing Network Pharmacology Approach and Experimental Validation

ObjectiveTo investigate the mechanism of the effect of Astragalus membranaceus (A. membranaceus) on lung adenocarcinoma at the molecular level to elucidate the specific targets according to the network pharmacology approach.MethodsThe active components of A. membranaceus and their potential targets were collected from the Traditional Chinese Medicine Systems Pharmacology Database. Lung adenocarcinoma-associated genes were acquired based on GeneCards, Online Mendelian Inheritance in Man (OMIM), PharmGKB, and Therapeutic Targets databases. The PI3K/AKT signaling pathway-related genes were obtained using Reactome portal. Networks of “ingredient-target” and “ingredient-target-pathway-disease” were constructed using the Cytoscape3.6.0 software. The relationships among targets were analyzed according protein-protein interaction (PPI) network. Finally, molecular docking was applied to construct the binding conformation between active ingredients and core targets. Cell counting kit 8 (CCK8) and Western blot assays were performed to determine the mechanism of the key ingredient of A. membranaceus.ResultsA total of 20 active components and their 329 targets, and 7,501 lung adenocarcinoma-related genes and 130 PI3K/AKT signaling pathway-related genes were obtained. According to Venn diagram and PPI network analysis, 2 mainly active ingredients, including kaempferol and quercetin, and 6 core targets, including TP53, MAPK1, EGF, AKT1, ERBB2, and EGFR, were identified. The two important active ingredients of A. membranaceus, kaempferol and quercetin, exert the therapeutic effect in lung adenocarcinoma partly by acting on the 6 core targets (TP53, MAPK1, EGF, AKT1, ERBB2, and EGFR) of PI3K/AKT signaling pathway. Expressions of potential targets in lung adenocarcinoma and normal samples were analyzed by using UALCAN portal and found that ERBB2 was overexpressed in lung adenocarcinoma tissues and upregulation of it correlated with clinicopathological characteristics. Finally, quercetin repressed viabilities of lung adenocarcinoma cells by targeting ERBB2 on PI3K/AKT signaling confirmed by CCK8 and Western blot.ConclusionOur finding unraveled that an active ingredient of A. membranaceus, quercetin, significantly inhibited the lung adenocarcinoma cells proliferation by repressing ERBB2 level and inactivating the PI3K/AKT signaling pathway.