Human Cytomegalovirus Infection Promotes High Expression Of TOP2A In Gliomas

Objective: Human cytomegalovirus(HCMV)infection is closely related to the modulatory effects of gliomas progression.It might increase the malignancy of the infected cell by disrupting cellular pathways involved in the cell cycle,apoptosis,angiogenesis,cell invasion and the host immune response.Topoisomerase(DNA)II alpha(TOP2A),an enzyme that controls and alters the topologic states of DNA during transcription,is aberrantly expressed in many cancers.However,few studies have investigated the relationship of the infection of HCMV and TOP2 A in glioma.The purpose of this study was to detect the expression of IE1 and TOP2 A in the glioma.And invesigate the relationship of the relationship of the infection of HCMV and TOP2 A in glioma.Methods: We retrieved six independent investigations from the Oncomine database and analysised the expression of TOP2 A in glioma tissues compared with corresponding normal controls.We used the Progno Scan database to analyze the correlation of TOP2 A expression with overall survival in GSE4271 and GSE4412 enrolled from the Gene Expression Omnibus(GEO)datasets with a total of 151 cases.A traditional immunohistochemical(IHC)staining was used to detect the IE1 and TOP2 A protein expression,and analyze the correlation of the expression of the two protein in the 58 cases of formalin-fxed paraffn-embedded(FFPE)of glioma.HCMV AD169 infected glioma U87 cells 2h after infection,we extracted protein.The expression level of IE1 and TOP2 A was detected by Western blot.We also detect the expression level of two proteins in vivo of animal by xenograft.We anlysised the expression of proteins applied IHC staining.Results: we analyzed six independent microarray datasets from Oncomine database,and revealed statistically signifcant over expression of TOP2 A in the majority of glioma tissues compared with normal brain controls(P=3.14í10-6,median rank=126.0).We found that TOP2 A expression is highly associated with overall survival of glioma patients[P=0.002735,HR=1.41(1.13-1.76)] [P=0.009506,HR= 1.37(1.08-1.73)].Immunohistochemical staining indicated that the expression of TOP2 A protein levels was frequently higher in the glioma tumor tissues than in peri-tumoral tissues(P<0.0001,t=4.578).Immunoreaction score distribution(IOD)of TOP2 A signifcantly increased along with grad stage of glioma(P<0.0001,F= 11.91).In all glioma tissues,IE1 positive rate was 98%(56/58),negative and weakly positive was 48%(28/58),strong positive rate was 52%(30/58).It was statistically signifcant over expression of TOP2 A in the strong positive glioma tissues compared with negative and weakly positive(P<0.0001,t=4.479).Western blot results showed that statistically signifcant over expression of TOP2 A in the HCMV infection group compared to the other control groups.In a xenograft mouse model of glioma,U87 cell infected with HCMV strain AD169 could enhanced growth and the expreesion(P=0.0133,t=5.265)of TOP2A(P<0.0001,t=5.447),compared with mock-infected groups.Conclusion: We found that high expression of TOP2 A in glioma was associated with poor prognosis of patients with glioma.There was a positive correlation between the infection of HCMV and TOP2 A.HCMV infection could exert its oncomodulatory potential in glioma.