Oleanolic Acid Inhibits the Proliferation and Invasion of U251Glioma Cells and Promotes their Apoptosis through the IKK-β, MAPK3, and MAPK4 Signaling Pathway

Object: To investigate the effects of Oleanolic acid (OA) on proliferation, apoptosis, migration, and invasion of human glioma cell U251, as well as IKK-β and MAPK signaling pathways.Methods: The binding of OA to IKK-β and MAPK signaling pathway essential proteins IKK-β, MAPK3, and MAPK4 was analyzed by molecular docking technique. U251 cells were treated with different concentrations of OA. The proliferation and apoptosis rates of U251 cells were detected by CCK-8 assay, MTT assay, cell cloning assay, and AnnexinⅤ FITC/PI double staining assay. Transwell chamber assay was used to detect migration and invasion of U251 cells. Western blot was used to detect and analyze the expression levels of CYP17A1, IKK-β, PTGS2 and MAPK3/4 protein in U251 cells after OA treatment. Finally, the transcriptome sequencing method was used to detect the differentially expressed genes in the two groups, and the GO and KEGG enrichment analysis were performed.Results: The results of molecular docking showed that OA could stably bind to IKK-β, MAPK3, and MAPK4 proteins. OA could not only effectively inhibit the proliferation and induce apoptosis of U251 cells (P < 0.05), but also significantly inhibit the invasion of U251 cells (P < 0.005). Western blot assay confirmed that OA could dramatically inhibit the protein expression levels of CYP17A1, IKK-β, PTGS2, MAPK3, and MAPK4 in U251 cells (P < 0.01). A total of 446 significantly differentially expressed genes were detected in transcriptome sequencing, of which 96 were up-regulated genes and 350 were down-regulated genes. These genes are mainly involved in processes such as inflammation, metabolism, immunity, and regulation of cell growth.Conclusions: OA may inhibit the proliferation, migration, and invasion of glioma U251 cells by binding key molecules of the IKK-β signaling pathway and essential target proteins of MAPK3 and MAPK4 in the MAPK signaling pathway.