Betulinic acid inhibits glioma cell viability by downregulation of NF-κB and enhancement of apoptosis

Abstract

Purpose: To determine the inhibitory potential of betulinic acid on pro-survival signaling pathway in glioblastoma.Methods: Changes in viabilities of glioma cells and primary astrocytes were measured using 3-(4, 5dimethylthiazol-2-yl)-2,  5-diphenyltetrazolium bromide (MTT) assay. Apoptotic changes were analyzed using Hoechst 33342 staining and Annexin V-FITC/PI kits. Western blotting was used for assaying the protein expressions of various pro-apoptotic and anti-apoptotic factors.Results: The proliferative potential of U87MG and A172 cells were significantly reduced on treatment with betulinic acid in a concentration- and time-dependent manner. Treatment with betulinic acid at a dose of 8.75 µg/mL increased apoptosis in U87MG and A172 cells to 41.8 ± 0.5 and 48.8 ± 0.5%, respectively (p < 0.05). Betulinic acid significantly decreased intracellular levels of NFκB p65 andsuppressed levels of survivin, XIAP and Bcl-2 in U87MG and A172 cells (p < 0.05). However, betulinic acid significantly increased the levels of Bax and activated caspase-9 and caspase-3 in U87MG and A172 cells (p < 0.05).Conclusion: Betulinic acid inhibited the proliferation of U87MG and A172 glioblastoma cells and mediated their apoptosis. There is need for in vivo studies for validation of the therapeutic potential of betulinic acid as an anti-glioblastoma drug. Keywords: Glioblastoma, Betulinic acid, Proliferation, Apoptosis, Chemotherapy, Intracranial malignancy