AG‐1031 induced autophagic cell death and apoptosis in C6 glioma cells associated with Notch‐1 signaling pathway

Abstract

Glioma is the most common primary brain tumor with high morbidity and poor prognosis. The effect of AG-1031, which is developed as an antineoplastic drug, on C6 glioma cells is still not clear. The aim of this research was to explore the effect of AG-1031 on C6 cells, and tried to find out its potential mechanism on cytotoxicity of C6 cells. The 3-(4,5-dimethylthiazol -2-yl) -2,5- diphenyltetrazolium bromide (MTT) assay showed that AG-1031 inhibited cell viability in a concentration-dependent manner, whereas 3-methyadenine (3-MA) reduced this effect. Results from hoechst 33342 staining and Western blot assay indicated that AG-1031 induced C6 cell apoptosis. Western blot assay presented that AG-1031 notably increased the LC3-II/LC3-I ratio and decreased the expression of P62. Besides, our results showed that bafilomycin A1 increased the expression of LC3-II in cells treated with AG-1031, which indicated that AG-1031 can increase autophagy in C6 cells. Meanwhile, Western blot assay showed that AG-1031 can inhibit Notch-1 signaling by testing relative protein expressions. The expression of the intracellular domain of Notch (NICD) also decreased according to immunofluorescence assay. Additionally, the activation of Notch-1 signaling alleviated AG-1031-induced autophagic cell death and apoptosis. Furthermore, phosphorylated Akt and its downstream effector mechanistic target of rapamycin (mTOR) were reduced with AG-1031. These results suggest that AG-1031 may induce autophagic cell death through the inhibition of Akt-mTOR signaling pathway by down-regulating Notch-1 signaling pathway and activating apoptosis in C6 cells via Notch-1 signaling, which develops a new target spot to treat glioma in the future.