Experimental Study Of TLR2 Promoting The Development Of Glioma By Enhancing Autophagy

Objective:Glioma is the most common malignant tumor of the central nervous system(CNS)and one of the most invasive human tumors.Current glioma treatments include surgical resection,radiation therapy and chemotherapy.However,due to the extreme invasiveness and therapeutic resistance of gliomas,these treatments are not effective in preventing tumor recurrence,resulting in lower 5-year survival.TLR2,a member of the pattern recognition receptor family,classically activates and mediates proinflammatory responses in innate immune cells by recognizing invading pathogens.There is increasing evidence that TLR2 is associated with cancer cell proliferation,invasion,metastasis and survival in a variety of tumors.Previous studies have found that TLR2 is closely linked to autophagy,but its role in glioma remains unknown.This study was aimed to evaluate the expression of TLR2 in human glioma tumors and its relationship with malignancy,tumor development and autophagy..It offers a new research direction for exploring targeted therapy of glioma.Methods:Glioma tissue eliminated from the neurosurgery at the Affiliated Hospital of Binzhou Medical College from January 2014 to December 2017 was randomly included.Of the 74 patients,32 were low-grade gliomas(LGG,WHOI-II),and 42 was high-grade gliomas(HGG,WHO ?-?).Western blot and Immunohistochemistry were utilized to detect the expression of LC3,Beclinl and TLR2 in 74 glioma specimens.We analyzed the prognosis of 551 glioma patients by Cancer Genome Atlas(TCGA).U87 human glioma cells were acquired from the Chinese Academy of Sciences cell bank,and TLR2 expression was manipulated using TLR2 plasmid transfection technology,and then induced with the TLR2 agonist Pam3CSK.Cell viability was detected by CCK-8,cell cycle was detected by flow cytometry,LC3II/I and p-p38/p38 were detected by immunoglobulin,and LC3 expression after over expression was detected by immunofluorescence.Results:TLR2 protein is mainly expressed in the cell membrane and cytoplasm.The expression of TLR2 in the high-grade glioma group was significantly higher than that in the low-grade group(LGG 0.4229±0.0404 vs HGG 0.5620±0.0269,P=0.0457).Clinical data correlation analysis suggested that TLR2 was closely associated with WHO classification(P=0.0314).Spearman correlation showed a positive correlation between TLR2 expression and the number of LC3 and Beclinl(r=0.3354,P=0.0035;r=0.3528,P=0.0021).Survival analysis showed a worse prognosis in patients with high TLR2 expression in low-grade gliomas(P<0.05).In U87 human glioma cells,cell activity was enhanced after TLR2 overexpression(P=0.0014).Overexpression of TLR2 accelerated the cell cycle(Scr-shRNA G2,10.02%±0.4989%vs TLR2-shRNA G2,16.00%±0.6809%).The conversion of LC3-? to LC3-? after TLR2 overexpression and the level of phosphorylated p38 were increased(both P<0.05).Conclusion:TLR2 promotes development and progression of human glioma via enhancing autophagy.