VEGF-C靶向USPIO分子探针的构建及其对肝癌细胞HepG2分子成像的初步研究

The construction of VEGF-C targeted USPIO molecular probe and its preliminary study on hepatocellular carcinoma cell line HepG2 for molecular imaging

目的以VEGF-C为靶向分子,选择USPIO作为载体,制备成具有特异性的靶向分子探针VEGF-C-USPIO,探讨其理化性质及体外成像特征。方法选用化学偶联法将载体USPIO与VEGF-C抗体连接,合成VEGF-C-USPIO靶向分子探针。用MTT法检测该探针对肝癌细胞株Hep G2细胞活性的影响;普鲁士蓝染色法检测细胞磁性标记情况,并对经过标记的细胞进行体外磁共振成像,观察其对磁共振信号强度的影响。结果成功合成了分子靶向探针VEGF-C-USPIO,MTT实验结果显示,不同浓度的靶向探针与Hep G2细胞作用不同时间,其对于细胞生长抑制率影响不大(P>0. 05);细胞普鲁士蓝染色结果显示,经标记了靶向探针VEGF-C-USPIO的细胞,其胞膜及胞浆含铁颗粒沉积较多,而未经过探针标记的对照组细胞胞膜及胞浆含铁颗粒沉积极少;细胞体外磁共振成像结果显示,经靶向探针标记的细胞,T2WI信号强度较未标记探针的对照组细胞降低,且随着探针剂量增加,信号强度逐渐降低(P <0. 05)。结论所合成的分子靶向探针VEGF-C-USPIO细胞毒性较小,其能够主动与肝癌细胞特异性结合,并通过磁共振信号强度的变化实现特异性成像。

Objective Using VEGF-C as a targeting molecule, USPIO was selected as a carrier to prepare a specific targeting VEGF-C-USPIO molecular probe to explore its physical and chemical properties and in vitro imaging characteristics. Methods The VEGF-C-USPIO targeting molecular probe was constructed by using the chemical coupling method to connect VEGF-C antibody with USPIO. The effect of the probe on the activity of HepG2 cells was detected by MTT assay. The magnetic labeling of cells was detected by Prussian blue staining. The labeled cells were subjected to in vitro magnetic resonance imaging to observe the effect of the probe on magnetic resonance signals. Results The molecular targeting probe VEGF-C-USPIO was successfully synthesized. The results of MTT assay showed that different concentrations of targeting probe had less effects on HepG2 cells at different times （ P 〉 0.05 ） ; Prussian blue staining showed that the cells labeled with VEGF-C-USPIO targeting probe had more deposition of iron-containing particles in the plasma membrane and cytoplasm, while, the control cells without probe labeling showed the opposite. The result of in vitro magnetic resonance imaging showed that the signal intensity of TzWI was lower than that of untreated probe, and the signal intensity was decreased with the increase of probe dose （ P 〈 0.05 ）. Conclusion The synthesized molecular targeting probe VEGF-C-USPIO has less cytotoxicity, which can specifically bind to liver cancer cells and can achieve specific imaging by the change of magnetic resonance signal intensity.