靶向肿瘤血管生成的体外MR分子成像的初步研究

Primary study of specific targeting of tumor angiogenesis by RGD-conjugated GoldMag^(TM)-CS nanoparticles with a clinical 3.0 T magnetic resonance scanner in vitro

目的应用GoldMagTM-CS纳米金磁微粒标记含RGD序列的环形多肽[cyclic arginine-glycine-aspartic-D-phenylalanine-lysine,c(RGDfK))]构建靶向肿瘤新生血管特异性分子探针并探讨其在体内MR成像的可行性。方法通过GoldMagTM-CS纳米金磁微粒与c(RGDfK)非共价键偶联方法构建特异性分子探针(RGD@GOLDMag)。利用流式细胞术观察RGD@GOLDMag与人脐静脉内皮细胞(HUVECs)结合的特异性。建立MR扫描序列,根据孵育HUVECs的探针的不同,分为A阳性组(RGD@GOLDMag孵育)、B阴性对照组(无关抗体和金磁颗粒耦合成的探针孵育)和C竞争抑制对照组[预先加入c(RGDfK)3、0 min后再加入RGD@GOLDMag孵育],另外设立2个空白对照组D及E(试管中只加水或凝胶)。利用临床应用的3.0 T磁共振扫描仪进行MR成像,观察其对磁共振信号的影响。结果成功构建了靶向血管生成的特异性MR分子探针;构建的MR分子探针能与HUVECs特异性地结合;并可显著降低T2*序列信号。竞争抑制对照组及阴性对照组信号无明显改变,信号差异具有统计学意义(P<0.05)。结论应用纳米金磁微粒及c(RGDfK)构建的MR分子探针能在临床应用的3.0 T磁共振扫描仪特异性的靶向肿瘤血管生成,有望应用于活体肿瘤新生血管的特异性显像。

Objective To prospectively evaluate the ability of cyclic arginine-glycine-aspartic-D-phenylalanine-lysine-conjugated-GoldMagTM-CS nanoparticles to depict tumor angiogenesis with a clinical 3.0 T MR scanner system in vitro.Methods Construction of MR Specific molecular probes used GoldMagTM-CS nanoparticles and c（RGDfK）by noncovalent bond couple.The capability of synthesized probes specific targeted to HUVECs was proved by observation of flow cytometry.MR scan sequence was established and the GoldMag solution in different concentration was scanned to ascertain the lowest concentration that could be detected by MR system.The ability of RGD@GOLDMag to noninvasivesily image tumor angiogenesis was evaluated using a clinical 3.0 T MR scanner in vitro（HUVECs）divided into five groups： RGD@GOLDMag group,no RGD@GOLDMag group,competitive group,water,and gelatin group.T＊2 weighted MRI was studied in Imaging Pro Plus 6.0.Unpaired student＇ t test were used for statistic analysis.Results RGD@GOLDMag was successfully constructed,which could specificely target HUVECs and obviously decrease the MRI signal intensity（SI）.The SI significantly decreased in group A compared with that of group B and group C（P0.05）.Conclusion RGD@GOLDMag has the potential to specifically detect and characterize tumor angiogenesis with a clinical 3.0 Tesla MR scanner in vitro.