Alan G. MacDiarmid Institute of Jilin University, Jilin University, Changchun 130012, China.
Macromol Biosci. 2013 Oct;13(10):1358-68. doi: 10.1002/mabi.201300137. Epub 2013 Jul 15.
A pH-responsive anticancer drug polymer conjugate p(aspartate)-graft-p(ethylene glycol)-dodecylamine-hydrazone-(adriamycin-levulinic acid) is synthesized as a magnetic resonance imaging (MRI)-visible and pH-sensitive drug delivery system. Being pH-sensitive, the anticancer drug ADR are stable in the polymeric micelles at neutral pH, resembling the physiological environment, whereas they release rapidly in acidic endosomal/lysosomal compartments of tumor cells for cancer therapy with the acid-linker breaking. For the purporse of MR imaging, the hydrophobic superparamagnetic iron oxide nanoparticles are encapsulated inside the core of the micelles. In order to identify the specific liver cancer tumors more efficiently, anti-vascular endothelial growth factor (anti-VEGF) is modified to the micelles. The stability studies show that all the conjugate@IO have excellent solubility and stability in stimulate biological media, suggesting that they have longer circulation time. Drug release studies in vitro show that the ADR release from the pH-sensitive polymeric micelles is significantly faster at pH 5.0 than at of pH 7.4. The tetrazolium dye method (MTT assay) shows that all the conjugate@IO exhibit low cytotoxicity and high antitumor activities against HepG2 cells. Furthermore, the anti-VEGF-conjugate@IO shows a high spin-spin (T2) relaxivity. In vivo MRI experiments on tumor-bearing mice demonstrate that the anti-VEGF-conjugate@IO achieves an appreciable accumulation into liver tumor, suggesting their potential utility as tumor-selective MRI contrast agents.
一种 pH 响应性抗癌药物聚合物偶联物 p(天冬氨酸)-graft-p(乙二醇)-十二烷基胺腙-(阿霉素-乙酰乙酸)被合成作为一种磁共振成像(MRI)可见且 pH 敏感的药物递送系统。由于具有 pH 敏感性,抗癌药物 ADR 在中性 pH 下的聚合物胶束中稳定,类似于生理环境,而在肿瘤细胞的酸性内涵体/溶酶体隔室中,它们会迅速释放,用于酸连接体断裂的癌症治疗。为了进行磁共振成像,疏水性超顺磁性氧化铁纳米粒子被包裹在胶束的核心内。为了更有效地识别特定的肝癌肿瘤,将抗血管内皮生长因子(anti-VEGF)修饰到胶束上。稳定性研究表明,所有缀合物@IO 在刺激生物介质中均具有优异的溶解度和稳定性,表明它们具有更长的循环时间。体外药物释放研究表明,在 pH 5.0 时,ADR 从 pH 敏感的聚合物胶束中的释放速度明显快于 pH 7.4 时。四唑染料法(MTT 测定)表明,所有缀合物@IO 对 HepG2 细胞均表现出低细胞毒性和高抗肿瘤活性。此外,抗 VEGF 缀合物@IO 表现出高自旋-自旋(T2)弛豫率。荷瘤小鼠的体内 MRI 实验表明,抗 VEGF 缀合物@IO 可显著积聚到肝肿瘤中,表明它们作为肿瘤选择性 MRI 对比剂具有潜在的应用价值。