Prognostic Value Of Ion Channel Gene In Glioblastoma And The Mechanism Of KCNB1 On Autophagy

Part One:A three ion channel genes-based signature predicts prognosis of primary glioblastoma patientsBackground:Increasing evidence suggests that ion channels not only regulate electric signaling in excitable cells but also play important roles in the development of brain tumor.However,the roles of ion channels in glioma remain controversial.Methods:In the present study,we systematically analyzed the expression patterns of ion channel genes in a cohort of Chinese patients with glioma using RNAseq expression profiling.First,a molecular signature comprising three ion channel genes was identifed using Univariate Cox regression and two-tailed student's t test conducted in overall survival(OS)and gene expression.We assigned a risk score based on three ion channel genes to each primary Glioblastoma multiforme(pGBM)patient.83 patients with pGBM were divided into high risk score group(n = 42)and low risk score group(n = 41)according to the median score.Next,we screened the three ion genes based signature in different molecular glioma subtypes.Gene ontology(GO)analysis and Gene Set Enrichment Analysis(GSEA)for the functional annotation of the signature.The findings in the present study have been validated in two independent cohorts(TCGA ad REMBRANDT datasets).Results:We demonstrated that pGBM patients who had a high risk of unfavorable outcome were sensitive to chemotherapy,and multivariate analysis indicated that the risk score was an independent predictor of survival.Next,we screened the three ion genes based signature in different molecular glioma subtypes.The signature showed a Mesenchymal subtype and wild-type IDH1 preference.Gene ontology(GO)analysis for the functional annotation of the signature showed that patients with high-risk scores tended to exhibit the increased expression of proteins associated with' apoptosis,immune response,cell adhesion and motion and vasculature development.Gene Set Enrichment Analysis(GSEA)results showed that pathways associated with negative regulation of programmed cell death,cell proliferation and locomotory behavior were highly expressed in the high-risk group.The findings in the present study have been validated in two independent cohorts.Conclusion:This three ion genes based signature provided a more accurate predictor of prognosis and showed the prospect in personalized cancer therapy.Part Two:Role of KCNB1 in the prognosis of gliomas and autophagy modulationBackground:In the first part,we found that KCNB1 was negatively correlated with the grade and prognosis of glioma.The molecular mechanism of KCNB1 on glioma progression was further studied in this study.Method:In this study,42 cases of independent glioma specimens were collected for qRT-PCR validation,and 41 cases of grade III and 83 cases of grade IV glioma specimens were collected for Kaplan-Meier survival analysis.First,the system biology was used to predict the function of KCNB1.Then immunofluorescence,immunofluorescence,flow cytometry,MTT and other techniques were used,through in vitro and in vitro experiments to verify the function of KCNB1.Results:qRT-PCR showed that KCNB1 expression was negatively correlated with grade,and survival analysis showed that KCNB1 overexpression group had better overall survival and progression-free survival.Biological analysis and experiments confirmed that KCNB1 has the function of promoting autophagy and apoptosis and inhibiting proliferation and invasion.KCNB1 promotes autophagy by activating ERK kinase,and further arresting ERK with U0126 and siERK1/2 will reduce autophagy.Mouse tumorigenesis experiments also demonstrated that KCNB1 has the function of inhibiting proliferation and promoting autophagy.Conclusion:Overall,our studies define KCNB1 as a novel prognostic factor for gliomas that exerts its tumor suppressive function through autophagy induction by activating ERK pathway.