RETRACTED: Deoxypodophyllotoxin inhibits cell viability and invasion by blocking the PI3K/Akt signaling pathway in human glioblastoma cells (Retracted article. See vol. 50, 2023)

Deoxypodophyllotoxin (DPT) is a natural chemical that has been demonstrated to inhibit cellular viability and motility in various cancer cell types. Although previous studies have indicated that programmed cell death and cell cycle arrest are involved in the suppression of glioma development by DPT, the underlying mechanism has not been fully explored. Different methods were used to the elucidate the mechanisms of DPT that inhibit the malignant behavior of glioma cells. Cellular viability was assessed by MTT assay. Relative protein and mRNA expression levels were detected by western blot analysis and reverse transcription-quantitative polymerase chain reaction analyses, respectively. Cell cycle distribution and the apoptosis rate were detected by flow cytometry. Hochest 33258 staining was also performed to detect apoptosis. Transwell assays without and with Matrigel were used to assess migration and invasion abilities, respectively. It was determined that DPT suppressed cellular viability by inducing cell cycle arrest at the G1/S phase by targeting the phosphatidylinositol 4,5-bisphosphate 3-kinase (PI3K)/RAC-alpha serine/threonine-protein kinase (Akt)-cyclin-dependent kinase inhibitor 1-cyclin-dependent kinase 2/cyclin E signaling cascades. Additionally, DPT significantly enhanced apoptosis by attenuating the PI3K/Akt-mediated suppression of Bcl-2-associated agonist of cell death expression, which was accompanied by an increased apoptosis regulator BAX/apoptosis regulator Bcl-2 ratio. Furthermore, DPT downregulated the invasiveness of glioma cells by hindering PI3K/Akt-matrix metalloproteinase (MMP)9/MMP2 signaling pathways. In conclusion, DPT effectively inhibited the expression of PI3K and downregulated PI3K/Akt-mediated signaling pathways to prevent glioblastoma progression.