Background: Ligustilide (LIG) and n-butylphthalide (NBP) have neuroprotective effects in cerebral ischemia; however, their roles in gliomas are not well-known.This study aimed to explore the anti-glioma effects of LIG and NBP individually and the synergistic effects of temozolomide (TMZ) via the PI3K/Akt Signaling Pathway.
Materials and Methods: Cytotoxicity of LIG and NBP alone and in combination with TMZ in U251 cells was determined using the CCk-8. The effect of compounds alone or in combination on cell migration was detected using the wound healing assay, and the invasion was evaluated by transwell assays, respectively. Cell apoptosis was quantified by flow cytometry and the changed expressions of proteins were detected by Western blotting.
Results: The results showed that LIG and NBP significantly inhibited the growth of U251 cells at concentrations of 4– 10 μg/mL and 1.5– 6 μg/mL in a dose-dependent manner (p< 0.05, p< 0.01). The combination of 20 μg/mL TMZ with LIG in the concentration range of 4– 10 μg/mL or with NBP of 0.5– 6 μg/mlachieved synergistic effect towardsU251 cells. LIG and NBP, alone or in combination with TMZ, markedly inhibited cell invasion (p< 0.001) and enhanced apoptosis (p< 0.05). The combination of TMZ with LIG or NBP markedly inhibited cell migration (p< 0.001). Western blot analysis showed that LIG, NBP, and TMZ, alone and in combination, significantly decreased the expression of Bcl-2, p-PI3K, and p-Akt, and increased the expression of Bax.
Conclusion: Both LIG and NBP exert anti-glioma effects on their own through the PI3K/Akt pathway and enhance TMZ-mediated anti-glioma efficiency via the same pathway.
Keywords: ligustilide, n-butylphthalide, glioma, synergistic effect, PI3K/Akt signaling pathway