THE ROLE OF BIOMARKER CANDIDATE GELSOLIN AND ITS MICRORNAS IN GLIOBLASTOMA

Abstract BACKGROUND Among potential glioblastoma (GBM) blood biomarkers that we identified recently, we focused on gelsolin (GSN), a key regulator of actin filament disassembly. GSN was significantly lower in the blood of patients with GBM than in that of healthy controls. In this study, we analyzed the function of GSN and identified microRNAs (miRs) involved in GSN expression in GBM. METHODS QRT-PCR and western blot were introduced to evaluate the expression level of GSN in normal brain and GBM tissue. The localization of GSN was examined by immunohistochemistry and immunocytochemistry using human samples. The association between the expression level of GSN and progression free survival (PFS) /overall survival (OS) in GBM was assessed by Kaplan-Meier analysis. The function of GSN and its signal transduction in glioma cell lines were analyzed using small interfering RNA (siRNA) knockdown of GSN. Additionally, miRs controlling GSN expression were retrieved from databases of miRs, and miRs related to GSN expression were identified in GBM tissues. RESULTS The expression level of GSN was significantly lower in GBM tissues compared to normal brains. Normal astrocytes mainly expressed GSN. High expressor of GSN showed longer PFS and OS than low expressor. Proliferation and invasion in glioma cell lines were significantly promoted by siRNA for GSN accompanied with the activation of glycogen synthase kinase 3β. In GBM tissues, the expression levels of GSN and miR-654-5p, 450b-5p showed an inverse correlation. The inhibitor for miR-654-5p and miR-450b-5p accelerated GSN expression resulting reduction of proliferation. CONCLUSION GSN plays a role as suppressor of proliferation and invasion in GBM. miR-654-5p and miR-450b-5p which control GSN expression can be targets against GBM.