| Background: Glioma is the most common intracranial malignant tumor,it is characterized by rapid infiltration of growth and postoperative high recurrence rate.The 5-year survival rate of low-grade glioma patients(World Health Organization WHO Class I and II)is about 30% to 70%,while the median survival time for high-grade glioblastoma(grade IV)is 9 to 12 months.Therefore,it is necessary to identify more malignant markers of this biomarker and potential therapeutic targets.MicroRNAs(miRNAs)are involved in a series of important biologic processes,such as cell development,differentiation,apoptosis,and proliferation.Aberrant miRNA expression is always associated with the occurrence and progression of various cancers.In addition,deregulated miRNAs can be diagnostic and prognostic biomarkers for cancers.The expression of miR-218 in gliomas was down-regulated,but little was found about the expression of miR-218 in gliomas.Meanwhile,mi R-218 has been shown to interact with two important molecules(HMGB1 and RAGE)in metastatic/invasive and anti-apoptotic activity in gliomas,whereas malignant gliomas are highly aggressive and strongly resistant The behavior of the deceased behavior causes its rapid infiltration to grow.Thus,we hypothesized that downregulation of miR-218 expression may be associated with the expression of HMGB1 and RAGE in gliomas and is associated with prognosis in patients with malignant tumors.Objective: In this study,we investigated the association between miR-218 and HMGB1/RAGE expression in glioma and the relation of miR-218 expression to the clinicopathologic features as well as the prognosis of patients with glioma,thereby obtaining clinical guidance for further mechanistic studies of miR-218 modulation in glioma.Methods:(1)The differential expression of miRNA was obtained by analyzing the glioma data in NCBI GEO database by bioinformatics.The differential expression miRNAs in gliomas were screened by PCR array(PCR kit containing 184 miRNA primer)in 22 cases of glioma tissue samples.The miRNAs with high difference in expression in gliomas were selected to explore their regulatory mechanism in gliomas,and the target genes of miRNAs were predicted by bioinformatics software.(2)The expression of miR-218 in 26 cases of non-tumor brain tissue and 66 cases of gliomas was detected by fluorescence quantitative PCR.The difference of miR-218 expression in different gliomas was analyzed.(3)The levels of HMGB1 and RAGE gene were detected by semi-quantitative PCR.The expression levels of HMGB1 and RAGE gene in non-tumor brain tissue and glioma were verified by quantitative PCR.The expression of HMGB1 and RAGE in non-tumor brain tissue and different grades of gliomas were analyzed.(4)The expression levels of HMGB1 and RAGE were detected by immunohistochemistry and Western blotting.The expression of HMGB1 and RAGE in non-tumor brain tissue and glioma were analyzed.(5)The patient's clinical data were collected and followed up.Univariate and multivariate Cox regression analysis was performed by Kaplan-Meier method and Cox regression analysis of survival curves of patients,to determine the effect of each clinical covariate and the expression levels of miR-218,HMGB1,RAGE in gliomas on patient survival.Results:(1)Twenty-two cases of glioma tissue were detected by PCR,and 11 mi RNAs with different expression were screened out.Based on the analysis of glioma data in NCBI GEO,seven mi RNAs with significant differences in expression were obtained.The miR-218 target gene HMGB1 and RAGE were predicted by bioinformatics based on its expression differences.(2)MiR-218 expression was detected in non-tumor brain tissue and glioma,and the expression level of miR-218 was different in different grades of gliomas.Compared with non-tumor brain tissue mi R-218 expression,mi R-218 expression and tumor grade showed an inverse correlation.The expression levels of mi R-218 in the high grade(grade ? and ?)glioma tissues were significantly lower than those in the low grade(grade ? and ?)(p <0.01).(3)PCR,immunohistochemical staining and Western blotting showed that HMGB1 and RAGE were detected in non-tumor brain tissue and different levels of glioma tissues.The expression of HMGB1 and RAGE was positively correlated with tumor grade,the expression of HMGB1 and RAGE was significantly higher than that of low grade(grade ? and ?)in high grade(grade ? and ?)glioma tissues(p<0.05).(4)Kaplan-Meier curve showed that the survival time of patients with low expression level of miR-218 was significantly shorter than patients with high expression level of miR-218,low expression level of HMGB1 and RAGE was significantly longer than patients with high expression level of HMGB1 and RAGE.(5)Univariate analysis showed that low expression of miR-218 was significantly associated with gender(p= 0.013),tumor size(p= 0.020),WHO grade(p<0.001)and KPS score(p<0.001),but with age and resection Level irrelevant.(6)Cox regression univariate analysis showed tumor size(p= 0.018),WHO grade(p<0.001),miR-218 expression level(p<0.001)as the independent survival time(OS)independent correlation factors;tumor size(p =(p<0.001),and the expression of miR-218(p<0.001)was an independent prognostic factor for progression-free survival(PFS).Cox regression multivariate analysis showed that the expression level of miR-218(HR = 0.32;95% CI 0.11,0.89;p= 0.029),extent of resection(HR = 0.11;95% CI 0.03,0.37;p< tumor size(HR = 0.39;95% CI 0.14,1.11;p= 0.029),and WHO classification(HR = 8.94;95% CI 0.11,1.94;p<0.001)were overall survival(OS)independent prognostic factor;miR-218 expression levels(HR = 0.46;95% CI 0.18,1.21;P = 0.011),extent of resection(HR = 0.09;95% CI 0.02,0.30;p<0.001),tumor size(HR = 0.53(HR = 2.10;95% CI 1.52,2.91;p<0.001)were independent prognostic factors for progression-free survival(PFS),and 95% CI 0.19,1.45;p= 0.031).Conclusions:PCR array and bioinformatics screened miRNA-218 differentially expressed in gliomas and showed a decreasing trend in glioma.Bioinformatics predicts HMGB1 and RAGE in gliomas as potential target genes for miR-218.The results showed that miR-218 could be as a tumor suppressor of miRNA in glioma.miR-218 was down-regulated in glioma and negatively correlated with HMGB1 and RAGE expression.The poor expression of miR-218 and HMGB1 and RAGE were predictive in the prognosis of glioma patients.miR-218 can influence the progression of glioma by modulating the expression of HMGB1-RAGE. |
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