Indirubin exerts anticancer effects on human glioma cells by inducing apoptosis and autophagy

Glioma causes significant mortality across the world and the most aggressive type of brain cancer. The incidence of glioma is believed to increase in the next few decades and hence more efficient treatment strategies need to be developed for management of glioma. Herein, we examined the anticancer effects of Indirubin against a panel of human glioma cells and attempted to explore the underlying mechanisms. The results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay showed that Indirubin could inhibit the growth of all the glioma cells but the lowest IC(50) of 12.5 µM was observed against the U87 and U118 glioma cells. Additionally, the cytotoxic effects of Indirubin were comparatively negligible against the normal astrocytes with an IC(50) of > 100 µM. Investigation of mechanism of action, revealed that Indirubin exerts growth inhibitory effects on the U87 and U118 glioma cells by autophagic and apoptotic cell death. Annexin V/PI staining assay showed that apoptotic cell percentage increased dose dependently. Apoptosis was associated with increase in Bax decrease in Bcl-2 expressions. Additionally, the expression of autophagic proteins such as LC3II, ATG12, ATG15 and Beclin 1 was also increased. Wound heal assay showed that Indirubin caused remarkable decrease in the migration of the U87 and U118 cells indicative of anti-metastatic potential of Indirubin. Taken together, these results suggest that Indirubin exerts potent anticancer effects on glioma cells and may prove essential in the management of glioma.