Boron neutron capture therapy inducing apoptosis in U87 glioblastoma cells

Abstract

Objective To explore the effect of boron neutron capture therapy(BNCT)on human brain glioma U87 cell line and its mechanisms.Method U87 cells in exponential phase were divided into 6 groups:untreated control,60Co γ 4 Gy,60Co γ 8 Gy,nuclear reactor exposure without boronophenylalanine (BPA)3.5 Gy,BNCT 4 Gy and BNCT 8 Gy.The anti-tumor effects were analyzed through cell morphology,the Annexin V/PI assay by flow cytometer(FCM),and methyl thiazolyl tetrazolium(MTT)assay.The expression of P53 protein was studied by immunocytochemistry and the expression of BCL-2 protein and BAX protein were measured by western blot.Results Typical morphological changes were observed after BNCT irradiation.The apoptotic rates were observed 48 h after irradiation with 65.1%and 85.9%for BNCT 4 Gy and 8 Gy.BNCT showed higher apoptotic rates than those of γ-ray control irradiation (P＜0.01).The expression level of P53 protein was negative in U87,while positive expression of P53 protein was observed in BNCT 4 Gy and 8 Gy groups.BNCT promoted BAX protein expression,at the same time it also inhibited BCL-2 expression.Conclusions BNCT can inhibit the growth of U87 significantly in a dose-dependent and time-dependent patterns. Key words: Boron neutron capture therapy; Glioma; Apoptosis