Study On The Expression Of TSP2 In Glioma And Its Effect On Biological Progress

Objective:Gliomas,especially high-grade gliomas,are highly malignant with a poor prognosis.Although existing treatments have improved the survival rate of glioma patients,the recurrence and mortality rates are still not ideal.The molecular mechanisms involved in the occurrence and development of glioma are still poorly understood.We previously reported that thrombospondin-2（TSP2）expression was increased in the tumor specimens from patients with glioma,promoting excitatory synapse formation and possibly contributing to hyperexcitability in the peritumoral cortex of glioma.However,little is known about the effect of TSP2 on the biological characteristics of glioma.Therefore,this study aimed to clarify the role of TSP2 in the biological progression of glioma.Methods:1.Surgical specimens of patients were collected.Study the expression level of TSP2protein in low-grade glioma（LGG）,high-grade glioma（HGG）and normal control cortex（Ctrl）,and find out the source of TSP2 protein.2.Culture the U251,U87MG and C6 glioma cells,and explore the effect of TSP2 protein on the migration and proliferation of glioma cells.And then,the TSP2 gene of C6 cells was overexpressed and knocked out respectively to obtain C6^TSP2+/+and C6^TSP2-/-cells.Take wild-type C6 cells(C6^WT)as a control to further explore the effect of TSP2 on the migration and proliferation of glioma cells.3.C6^WT,C6^TSP2+/+and C6^TSP2-/-cells were implanted into Wistar rats（P21,male）to establish glioma transplantation models.MRI was used to track continuously and explore the effect of TSP2 on the growth of glioma in vivo.4.The surgical specimens were collected.Immunofluorescence technology was used to study the changes in the number of excitatory synapses and inhibitory synapses in the cerebral cortex adjacent to gliomas,in order to explore the role of TSP2 in it.Results:1.Compared with normal cortex,the expression of TSP2 protein in glioma is higher,and the expression in HGG is higher than that in LGG.The TSP2 whose expression is up-regulated is mainly derived from gliomas,partly from reactive astrocytes and neurons.2.Exogenous addition of appropriate concentration of TSP2 protein can promote the migration of U251,U87MG and C6 cells,but does not affect their proliferation.TSP2overexpression can simultaneously promote the migration and proliferation of C6 cells,while the migration and proliferation of C6 cells are inhibited after TSP2 knockout.3.In the glioma transplantation model,TSP2 overexpression promotes the malignant growth of gliomas,while TSP2 knockout delays and inhibits the growth of gliomas.The overexpression of TSP2 also increased the mortality of glioma transplantation models.4.Compared with the normal control cortex,the number of excitatory synapses in the cortex around the glioma tumor is increased,and the peritumoral cortex of HGG is higher than that of LGG,while the number of inhibitory synapses has no significant change.Conclusions:TSP2,which is mainly derived from glioma,may promote the development of glioma by promoting the migration and proliferation of glioma cells,and at the same time promote the excitability of the neural network of the cerebral cortex adjacent to the tumor,thereby affecting the prognosis of patients with glioma.