Expression and prognostic role of ribophorin II in gliomas

Abstract

Objective To investigate the expression of ribophorin Ⅱ (RPN2) in gliomas and its relationship to clinical features and prognosis. Methods The clinical data and mRNA-seq data of 309 glioma samples were collected from Chinese Glioma Genome Atlas (CGGA) and the expression of RPN2 was retrospectively analyzed. The 30 glioma samples were collected by Beijing Tiantan Hospital Affiliated to Capital Medical University from 2016 to 2017. RT-qPCR was used to test RPN2 mRNA expression in those samples. TCGA mRNA sequencing and REMBRANDT mRNA array datasets were simultaneously used as validation datasets. The expression pattern of RPN2 in gliomas was analyzed by t-test and ANOVA. The relationship of RPN2 expression to the patient’s overall survival was estimated by Kaplan-Meier method, log-rank test and Cox regression analysis. The DAVID software was used to investigate the RPN2 functions in GO biological processes and KEGG pathways. Results In WHO Ⅱ, WHO Ⅲ and WHO Ⅳ gliomas, RPN2 expression was up-regulated along with glioma grade progression (-0.55±0.61、0.05±0.66 and 0.36±1.20, respectively, P<0.0001), which was further confirmed by RT-qPCR experiment. The expression of RPN2 was the lowest in neural subtype and highest in mesenchymal subtype (-0.80±0.56 and 0.68±1.02, respectively, P<0.0001). RPN2 expression in IDH-mutant gliomas was significantly lower than that in IDH-wild gliomas (-0.22±0.77 and 0.22±1.18, respectively, P<0.001). The overall survival of patients with high expression of RPN2 was significantly lower than that of patients with low expression (P<0.0001). Similar results were obtained in both TCGA mRNA-seq and REMBRANDT mRNA microarray datasets. Multi-variate Cox analysis showed that RPN2 expression was an independent predictor of prognosis (P=0.004). RPN2 might be related to the apoptosis, division, proliferation, adhesion and angiogenesis. Conclusion The expression of RPN2 seems to be associated with the malignant degree of gliomas and may be a prognostic marker and potential therapeutic target. Key words: Glioma; Gene expression profiling; Prognosis; Ribophorin Ⅱ; Biological process