靶向整合素α_vβ_3受体的新型RGDyC-PEG-PAMAM纳米探针的设计制备、~(131)I标记及其质量控制

本研究以具有优良生物学性能的聚酰胺-胺树状大分子(PAMAM)为纳米载体,将具有肿瘤靶向性的精氨酸-甘氨酸-天冬氨酸(RGD)与纳米载体相连,并通过放射性核素~(131)I进行标记,对标记物的体内外药效学性质进行评价,探讨将其应用于肿瘤特异显像和靶向治疗的可能性。从多肽化学修饰法角度设计精氨酸-甘氨酸-天冬氨酸-酪氨酸-半胱氨酸(RGDyC),利用点击化学法引入双功能基团PEG(NHS-PEG-MAL),采用"一锅两步"法制备RGDyC-PEG-PAMAM纳米复合物,通过核磁共振和紫外光谱进行表征确定产物,并检测纳米粒径分布和电位,用透射电镜(TEM)观察其形态大小及分布;进一步采用氯胺T法进行~(131)I标记,并测定标记率、标记物的稳定性及脂水分配系数。所设计的RGDyC-PEG-PAMAM纳米复合物制备产率为62.09%,~(131)I对其标记率为94.68%~98.87%,标记物在体外72h后放化纯大于80%,脂水分配系数lg P(正辛醇/水)为-1.59±0.09。所设计的RGDyC-PEG-PAMAM可采用氯胺T法成功完成~(131)I标记,制备与标记过程高效、简捷,标记物~(131)I-RGDyC-PEG-PAMAM具有良好稳定性和较高亲水性,成药性良好,为后期进一步考察体外肿瘤细胞摄取与生长抑制、评估人癌裸鼠异种移植瘤模型治疗及肿瘤显像等体内外药效学研究奠定了基础,~(131)I-RGDyC-PEG-PAMAM有可能作为一个新型SPECT探针应用于肿瘤特异显像与靶向治疗。

Design and Preparation of Novel RGDyC-PEG-PAMAM Nanoprobe Targeting Integrin αvβ3 Receptor, 131I Labeling and Its Quality Control

In this study, arginine-glycine-aspartic acid(RGD) with tumor targeting was attached to the polyamidoamine dendrimers(PAMAM) with excellent biological properties as the nanocarrier labeled with radionuclide ¹³¹I. The pharmacodynamic properties of the labeled compounds in vivo and in vitro were evaluated, and the possibility of applying them to tumor-specific imaging and targeted therapy was discussed. The structure of the peptide Arg-Gly-Asp-Tyrosine-Cysteine(RGDyC) was determined by the chemical modification method, and then the double functional group(NHS-PEG-MAL, PEG) was introduced by the chemical method of click chemistry using “one pot two step” preparation. Nanocomposites were characterized by ¹H NMR and UV spectroscopy. And then particle size distribution and potential were detected. The morphology and size distribution were characterized by transmission electron microscopy(TEM). Chloramine T method was used to label ¹³¹I, and the labeling rate, marker stability and water partition coefficient were determined. The yield of RGDyC-PEG-PAMAM nanocomposite is 62.09%. The labeling rate of RGDyC-PEG-PAMAM is 94.68%-98.87%. The radiochemical purity of the marker in vitro is above 80%. Water partition coefficient, lg P(n-octanol/water) is -1.59±0.09. The designed RGDyC-PEG-PAMAM can successfully complete the ¹³¹I labeling with the chloramine T method. The preparation and labeling process is efficient and simple. The labeling product ¹³¹I-RGDyC-PEG-PAMAM has good stability, high hydrophilicity and good druggability. The results laid the foundation of pharmacodynamics study in vivo and in vitro, including further assess of the tumor cell uptake and growth inhibition in vitro, human tumor xenograft model therapy and tumor imaging. The results show that ¹³¹I-RGDyC-PEG-PAMAM can be used as a novel SPECT probe for tumor-specific imaging and targeted therapy.