TLR2 promotes development and progression of human glioma via enhancing autophagy

Abstract

ObjectiveIn this study, we aim to evaluate Toll-like receptor 2 (TLR2) expression in human glioma tumors and the correlation between its expression with degrees of malignancy and autophagy, development of tumors. MethodImmunohistochemistry and Western blot were carried out to determine the expression of LC3, Beclin1 and TLR2 in 74 glioma specimens. We analyzed the prognosis of 551 glioma patients through the Cancer Genome Atlas (TCGA). To determine the effect of TLR2 in glioma, we manipulated TLR2 expression using TLR2 plasmid transfer technique in U87 human glioma cell. ResultsTLR2 expression in high-grade was significantly higher than that in low-grade glioma group (P < 0.05). TLR2 was positively correlated with tumor grade (P < 0.05). Spearman correlation showed that the expression of TLR2 was positively correlated with the numbers of LC3 and Beclin1 (P < 0.05). The patients with high TLR2 expression had a poorer outcome compared with the patients with low TLR2 in low-grade glioma (P < 0.05). TLR2 overexpression enhances glioma cell activity and accelerates cell cycle progression. In addition, treatment with TLR2 overexpression increases the conversion rate of LC3-I to LC3-II and enhances the level of phosphorylated p38. ConclusionTLR2 promotes development and progression of human glioma via enhancing autophagy.