2-脱氧-D-葡萄糖标记的氧化铁纳米粒子对裸鼠A549肺腺癌的靶向对比增强作用

2-deoxy-D-glucose modified supermagnetic iron oxide nanoparticles enhance the contrasting effect on MRI of human lung adenocarcinoma A549 tumor in nude mice

目的 探讨2-脱氧-D-葡萄糖（2-DG）标记的氧化铁纳米粒子γ-Fe2O3@DMSA-DG NPs作为磁共振成像（MRI）对比剂检测肿瘤的功能.方法 制备γ-Fe2O3@DMSA-DG NPs纳米粒子.采用普鲁士蓝染色、比色法、MRI T2WI及多回波序列检测A549细胞靶向吸收γ-Fe2O3@DMSA-DG NPs的情况,以γ-Fe2O3@DMSA NPs作为对照剂,游离D-葡萄糖作为竞争性抑制剂.制备A549细胞荷瘤裸鼠,并经尾静脉注射γ-Fe2O3@DMSA-DG NPs或γ-Fe2O3@DMSA NPs冻干粉的无菌水悬液,注射前和注射后6、12、24、48 h进行MRI检查,测量肿瘤组织、脑组织、肝组织及大腿部骨骼肌的T2信号强度和肿瘤组织的T2值.结果 γ-Fe2O3@DMSA NPs和γ-Fe2O3@DMSA-DG NPs粒径无明显差异,平均粒径约为10 nm.红外光谱图显示,γ-Fe2O3@DMSA-DG NPs表面有C-N伸缩振动峰,表明2-DG成功标记到γ-Fe2O3@DMSA NPs的表面.普鲁士蓝染色、比色法、MRI T2WI及多回波序列检测显示,生长高峰期的A549细胞在2h内吸收γ-Fe2O3@DMSA-DG NPs明显多于γ-Fe2 O3@DMSA NPs,而且吸收的γ-Fe2O3@DMSA-DG NPs能够被游离D-葡萄糖有效抑制.体内实验显示,实验组荷瘤裸鼠在-Fe2O3@DMSA-DG NPs注射前和注射后6、12、24、48 h,肿瘤组织的T2信号强度分别为（326.00±16.26）s、（276.40±5.13）s、（268.40±30.58）s、（240.40±25.93）s和（262.20±30.04）s,肿瘤组织的T2值分别为（735.80±20.93）ms、（645.80±69.58）ms、（615.00±124.61）ms、（570.60±67.78） ms和（537.80±105.29） ms；而对照组荷瘤裸鼠在γ-Fe2 O3@DMSA NPs注射前和注射后6、12、24、48 h,肿瘤组织的T2信号强度分别为（335.60±4.93）s、（290.80±5.93）s、（273.40±15.08）s、（327.40±16.65）s和（313.20±20.45）s,肿瘤组织的T2值分别为（686.00±21.44） ms、（617.80±69.93） ms、（645.20±85.89） ms、（669.40±13.72） ms和（608.80±61.90）ms.注射γ-Fe2O3@DMSA-DG NPs或γ-Fe2O3@DMSA NPs的荷瘤裸鼠,其肝脏信号强度均有明显下降,脑组织及骨骼肌信号强度无明显变化.结论 γ-Fe2O3@DMSA-DG NPs有靶向肿瘤过表达葡萄糖受体的功能,可作为靶向肿瘤的MRI对比剂.

Objective To evaluate the role of 2-deoxy-D-glucose （2-DG） modified supermagnetic iron oxide nanoparticles （SPIO） （γ-Fe2O3@DMSA-DG NPs） in tumor detection as a magnetic resonance imaging （MRI） contrast agent.Methods γ-Fe2O3@DMSA-DG NPs was prepared.The degree of A549 cells targeted absorption of γ-Fe2O3@DMSA-DG NPs was detected by Prussian blue staining,colorimetric assay,T2W and multi-echo sequence MRI.γ-Fe2O3@DMSA NPs was used as a control agent,and free D-glucose as a competitive inhibitor.Human lung adenocarcinoma A549 xenograft tumor was prepared in nude mice.Sterile aqueous suspension of γ-Fe2O3@DMSA NPs or γ-Fe2O3@DMSA-DG NPs was injected into the tail vein of nude mice.Before and 6,12,24,48 h after injection,MRI imaging of the mice was performed.T2 signal intensity of the tumor,brain,liver and thigh skeletal muscles,and T2 values of the tumors were measured.Results The average diameter of the particles was about 10 nm,and there were no significant differences between the diameters of γ-Fe2O3@DMSA NPs and γ-Fe2O3@DMSA-DG NPs.The IR spectra showed the C-N retractable vibration peak at γ-Fe2O3@DMSA-DG NPs surface,indicating that 2-DG was conjugated to the γ-Fe2O3@DMSA NPs.The Prussian blue staining,colorimetric assay,MRI T2 signal intensity and T2 values revealed that γ-Fe2O3@DMSA-DG NPs were significantly more absorbed by A549 cells at growth peak than γ-Fe2O3@DMSA NPs,and the absorption of γ-Fe2O3@DMSA-DG NP was inhibited by free D-glucose.The results of in vivo examination showed that before and at 6,12,24,48 h after injection of γ-Fe2O3@DMSA-DG NPs,the mean T2 signal intensities of the tumors were （326.00 ±6.26）s,（276.40 ±.13）s,（268.40±0.58）s,（240.40 ±5.93）s,（262.20±0.04）s,respectively,and the T2 values of the tumors were （735.80 ±20.93） ms,（645.80 ±69.58） ms,（615.00 ±24.61） ms,（570.60 ±67.78） ms,and （537.80 ±105.29） ms,respectively.However,before and at 6,12,24,48 h after injection of γ-Fe2O3@DMSA NPs,the mean T2 signal intensities of the tumors were （335.60±.93）s,（290.80±.93）s,（273.4O±5.08）s,（327.40 ±6.65）s,and （313.20 ±0.45）s,respectively,and T2 values were （686.00 ±21.44） ms,（617.80 ±69.93） ms,（645.20 ±85.89） ms,（669.40 ±13.72） ms,and （608.80 ±61.90） ms,respectively.The T2 signal intensity and T2 value of the tumors were not declined generally after injection.The liver T2 signal intensity was decreased after injection of both γ-Fe2O3@DMSA-DG NPs and γ-Fe2O3@DMSA NPs,and T2 signal intensity of the brain and muscle did not show significant changes.Conclusions γ-Fe2O3@DMSA-DG NPs has an ability to target glucose receptors overexpressed in tumors,and may serve as a MRI contrast agent for tumor detection.