Effects of Galbanic Acid on Proliferation, Migration, and Apoptosis of Glioblastoma Cells Through the PI3K/Akt/MTOR Signaling Pathway.

Abstract

Glioblastoma is one of the most aggressive tumors of the central nervous system. Galbanic acid, a natural sesquiterpene coumarin, has shown favorable effects on cancerous cells in previous studies. The aim of the present work was to evaluate the effects of galbanic acid on proliferation, migration, and apoptosis of the human malignant glioblastoma (U87) cells. The anti-proliferative activity of the compound was determined by the MTT assay. Cell cycle alterations and apoptosis were analyzed via flow cytometry. Action on cell migration was evaluated by scratch assay and gelatin zymography. Quantitative Real-Time PCR was used to determine the expression of genes involved in cell migration (matrix metalloproteinases, MMPs) and survival (the pathways of PI3K/Akt/mTOR and WNT/β-catenin). Alteration in the level of protein Akt was determined by Western blotting. Galbanic acid significantly decreased cell proliferation, inhibited cell cycle, and stimulated apoptosis of the glioblastoma cells. Moreover, it could decrease the migration capability of glioblastoma cells, which was accompanied by inhibition in the activity and expression of MMP2 and MMP9. While galbanic acid reduced the gene expression of Akt, mTOR, and PI3K and increased the PTEN expression, it had no significant effect on WNT, β-catenin, and APC genes. In addition, the protein level of p-Akt decreased after treatment with galbanic acid. The effects of galbanic acid were observed at concentrations lower than those of temozolomide. Galbanic acid decreased proliferation, cell cycle progression, and survival of glioblastoma cells through inhibiting the PI3K/Akt/mTOR pathway. This compound also reduced the migration capability of the cells by suppressing the activity and expression of MMPs.