The Expression Of Tissue Factor In Glioma And Its Relationship With Epithelial-mesenchymal Transition Of Glioma Cells

Background and objective: Glioma is one of the most common primary intracranial tumors,which is difficult to be completely removed,has high postoperative recurrence rate and poor prognosis,especially high-grade glioma.The aggressive phenotype of glioma cells is the main reason for its treatment failure.In the process of acquiring this aggressive phenotype,epithelial-mesenchymal transition(EMT)plays an important role.This process can endow glioma cells with aggressiveness and cancer stem cells characteristics,thereby promoting tumor development,maintaining tumor growth and contributing to recurrence after treatment.Tissue factor(TF)is a transmembrane glycoprotein,which is highly expressed in many types of tumors including glioma.It is currently believed that TF can significantly increase the risk of venous thromboembolism in tumor patients and contribute to tumor angiogenesis,which is closely related to tumor growth,invasion and metastasis.In some cases,EMT can participate in the regulation of TF expression.However,the effect of EMT in glioma cells on TF expression is still unclear,and whether TF has a regulatory effect on glioma cells EMT has not been studied.The purpose of this study is to explore the relationship between TF and EMT in glioma.Methods: Tissue specimens were collected from glioma patients surgically resected,and immunohistochemical method was used to detect TF expression level in the tissue sections.Then experiments in vitro of cells were carried out,glioma U87 and LN18 cells were cultured,different concentrations of TGF-β1 was used to induce EMT in glioma cells,and qPCR and western blotting were used to detect TF mRNA and protein expression.Small interfering RNAs were used to knock down TF,western blotting and scratch experiments were used to study the effect of inhibiting TF expression on glioma cells EMT and the cells migration and invasion.Results: 1.The results of immunohistochemistry showed that TF positive cells percentage in the normal control group was(3.24±1.21)%,in the low-grade glioma group was(18.84±3.30)%,and in the high-grade group was(40.70±4.86)%.TF positive cells percentage among the groups was statistically significant(P<0.0001),and the TF expression level was positively correlated with the WHO classification of glioma(rs=0.663,P<0.01).2.After induction of EMT in glioma cells,the expression levels of TF mRNA and protein in glioma cells were significantly increased.3.Knockdown of TF could inhibit the expression of EMT-related markers(E-cadherin,N-cadherin,β-catenin and vimentin)and transcription factors(snail and slug)in glioma cells,and inhibit the migration and invasion of glioma cells.Conclusions:1.Compared with normal brain tissue,TF expression level in glioma tissue is significantly higher,and TF expression level is positively correlated with the WHO classification of glioma.2.EMT in glioma cells can promote the expression of TF.3.TF can regulate the EMT process of glioma cells and the cells migration and invasion.