The Effects And Mechanisms Of EZH2 In Glioblastoma

Objective To investigate the effects and mechanisms of EZH2 on tumor immune response in glioma.Methods The C6 glioma stem cell line was established and the EZH2 knock down glioma stem cell line was constructed by lentiviral transfection.The proliferation of shEZH2 glioma stem cells was observed by CCK-8 kit and cell counting.The apoptosis was detected by 7-AAD and Annexin V.The expressions of MHCII,PD1 and PDL1 on the surface of shEZH2 glioma stem cells were determined by flow cytometry.EZH2 knock down glioma stem cells were intracranial injected in the brain of C57BL/6 mice and the mice survival curves were observed.The pathology of the tumor was estimated by HE staining.The infiltrated lymphocytes of T cells and NK cells in the brain were analyzed by flow cytometry.Results 1.C6 glioma stem cell tumor spheres were formed in serum-free stem cell medium and Nestin expression was 72.2%.The EZH2 knock down C6 glioma stem cells was successfully established by lentivirus transfection and verified by Real time-PCR and western blot.2.The EZH2 knock down cells proliferation began to decrease on the day 5 of cell culture,meanwhile the apoptosis increased.The suspension tumor stem cell spheres decreased and stem cells differentiation increased and adherent.3.EZH2 knockdown increased the expression of MHC II and PDL1.4.EZH2 knock down glioma stem cells decreased brain tumor growth and prolonged the animal's survival.5.The infiltrated lymphocytes in the brain were increased,including CD4+,CD8+T cells and NK cells.But the proportion of Treg cells in the brain were reduced.Conclusions EZH2 gene knockdown inhibited the growth of glioma cells,promote the differentiation and apoptosis of tumor stem cells.Decreasing EZH2 changed the expression of tumor cell surface antigen,affected tumor immune response,inhibiting tumor growth and prolonging the survival rate of mice.