硼中子俘获疗法诱导U87胶质瘤细胞凋亡

目的 探讨硼中子俘获疗法(BNCT)对人脑胶质瘤细胞株U87的增殖抑制和诱导凋亡的作用及可能机制.方法 实验分为未照射组(0 Gy)、γ射线对照组(4、8 Gy)、反应堆组(3.5 Gy)、BNCT组(4、8 Gy).采用形态观察、流式细胞仪Annexin V/PI荧光染色、四甲基偶氮唑蓝(MTT)法等方法观察BNCT对U87细胞的增殖抑制和诱导凋亡的作用,以免疫组织化学技术检测P53蛋白的表达,应用western blot检测BCL-2、BAX蛋白表达的变化.结果 硼中子照射后细胞出现典型的凋亡形态改变.BNCT 4、8 Gy组处理后48 h细胞的凋亡率分别为65.1%、85.9%.BNCT 4、8 Gy组细胞生长抑制作用显著高于同等剂量的γ射线照射组(P＜0.01).未照射的U87细胞P53蛋白表达阴性,BNCT4、8 Gy照射后P53蛋白表达阳性.BNCT4、8 Gy照射后BCL-2蛋白表达下降,BAX蛋白上升.结论 BNCT对U87细胞具有显著的增殖抑制作用,并有剂量、时间依赖性特点.

Boron neutron capture therapy inducing apoptosis in U87 glioblastoma cells

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.