预定位反义探针的血药动力学及急性毒性研究

Pharmacokinetics and Acute Toxicity of Pretargeting Antisense Oligonucleotide Molecular Probes in Animals

目的研究188Re标记的反义分子探针cMORF的血药动力学与急性毒性作用。方法制备反义寡核苷酸MORF与人源性单抗赫赛汀(Herceptin)的偶联物,利用双功能螯合剂NHS-MAG3作为连接剂分别对MORF-Herceptin偶联物及与MORF互补的反义寡核苷酸cMORF进行188Re的放射性标记,观察188Re标记物的血药动力学、体内生物分布及急性毒性实验。结果 188Re-cMORF标记率为60%～80%,放化纯度>90%,具有体外稳定性好及保持与其互补链的杂交特性。188Re-Herceptin-MORF的标记率大于90%,其免疫活性为62%～71%,具有良好的体外稳定性。与188Re-Her-ceptin-MORF相比较,188Re-cMORF注射后血中清除速度比较快,主要分布在肾脏、肝脏等器官;而188Re-Herceptin-MORF在血液中有较高的放射性分布且血循环时间较长。注药后48h,实验动物均未见不良反应与死亡。结论 188Re-cMORF具有良好的组织分布特点,无急性毒性作用,可用来作为一种分子影像探针用于活体的肿瘤反义显像。

Objective To study the pharmacokinetics and bio-safety of cMORF antisense oligonucleotide molecular probe labeled with rhenium-188（188Re-cMORF）mediated by Herceptin monoclonal antibody.Methods Antisense oligonucleotide morpholinos（MORF）,a DNA analogue,was conjugated with human monoclonal antibody Herceptin.188Re-Herceptin-MORF and 188Re-cMORF were prepared by NHS-MAG3 as chelating agent.The pharmacokinetics,biodistribution and the acute toxicity test of 188Re-cMORF and 188Re-Herceptin-MORF were performed.Results The labeling rate of 188Re-cMORF was about 60% to 80%.The radiochemical purity was above 90%.188Re-cMORF had a good stability in vitro and the ability to hybridize to the MORF.The labeling rate of 188Re-Herceptin-MORF was above 90%.188Re-Herceptin-MORF had a better stability in vitro and with the immunoreactivity of 62% to 71%.Compared to 188Re-Herceptin-MORF,188Re-cMORF had more rapid blood clearance and the combining rate with serum protein of 7%-10%.The biodistriibution study in normal animals showed that there was high uptake in kidney and liver for 188Re-cMORF and higher radioactivity levels in blood and a long retain time in blood stream for 188Re-Herceptin-MORF.All animals were present well after injection of high dose of 188Re radiolabel.Conclusion Labeling cMORF with 188Re is simple,efficient and with good stability.188Re-cMORF has no acute toxicity effect to animals and appears to be suitable for further antisense imagiing application in live body as a molecular imaging probe.